diff options
| author | nfenwick <nfenwick@pglaf.org> | 2025-02-05 21:40:42 -0800 |
|---|---|---|
| committer | nfenwick <nfenwick@pglaf.org> | 2025-02-05 21:40:42 -0800 |
| commit | 8cee421818ba0f4f66d36392551d038e64f5961c (patch) | |
| tree | 7c0182cc48417cc726d3ba67bc708966692dd16f /old/52074-0.txt | |
| parent | 6c68b847e690cac3b127f909d937f34bde43289f (diff) | |
Diffstat (limited to 'old/52074-0.txt')
| -rw-r--r-- | old/52074-0.txt | 4365 |
1 files changed, 0 insertions, 4365 deletions
diff --git a/old/52074-0.txt b/old/52074-0.txt deleted file mode 100644 index 2100d51..0000000 --- a/old/52074-0.txt +++ /dev/null @@ -1,4365 +0,0 @@ -Project Gutenberg's Soldering, Brazing and Welding, by Bernard E. Jones - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: Soldering, Brazing and Welding - -Editor: Bernard E. Jones - -Release Date: May 15, 2016 [EBook #52074] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK SOLDERING, BRAZING AND WELDING *** - - - - -Produced by deaurider, Harry Lamé and the Online Distributed -Proofreading Team at http://www.pgdp.net (This file was -produced from images generously made available by The -Internet Archive) - - - - - - - - Transcriber’s Notes: - - Bold, italics, superscript and subscript text have been trancribed as - =text=, _text_, ^{text}, and _{text}, respectively. Small capitals - have been replaced with capitals. Letters between square brackets such - as [T] and [V] indicate T- and V-shaped symbols rather than letters. - - More transcriber’s Notes may be found at the end of this text. - - - - - Soldering, Brazing - and Welding - - EDITED BY - BERNARD E. JONES - Editor of “Work” - - With 78 Illustrations - - [Illustration] - - FUNK & WAGNALLS COMPANY - NEW YORK and LONDON - 1917 - - - - -EDITOR’S PREFACE - - -This handbook, which explains in detail a variety of processes common to -general metalworking, has been written by a number of thoroughly -practical men, by whom it was contributed in another form to “Work,” the -illustrated weekly journal of handicrafts and mechanics. Its appeal is -to everybody who makes any attempt at working in metals, inasmuch as at -least one of the processes--soldering, brazing or welding--will be met -at a very early stage in the beginner’s experience. This handbook will -be found a complete workshop guide to the usual methods of soldering and -brazing, and will form an excellent introduction to the modern -electrical and oxy-acetylene welding processes, to do complete justice -to which, however, a separate handbook would, of course, be necessary. -If readers encounter difficulty in any of the matters treated in this -book, they have only to write to “Work,” in whose columns (but not by -post) help will be willingly afforded. - - B. E. J. - - - - -CONTENTS - - - CHAPTER PAGE - - 1. VARIOUS PROCESSES OF JOINING METALS 1 - - 2. SOFT SOLDERS 4 - - 3. FLUXES USED IN SOFT-SOLDERING 12 - - 4. SOFT-SOLDERING WITH THE COPPER BIT 17 - - 5. SOFT-SOLDERING WITH BLOWPIPE OR BUNSEN BURNER 37 - - 6. SOLDERING ALUMINIUM 57 - - 7. WIPING JOINTS ON LEAD PIPES 64 - - 8. HARD-SOLDERING WITH SILVER SOLDER 75 - - 9. SOLDERING GOLD AND SILVER JEWELLERY 83 - - 10. BRAZING 89 - - 11. WELDING IRON AND STEEL UNDER THE HAMMER 108 - - 12. MAKING BLOWPIPES 112 - - 13. MANAGING BLOW-LAMPS 118 - - 14. MAKING BLOW-LAMPS 122 - - 15. ELECTRIC AND THERMIT WELDING BRIEFLY CONSIDERED 129 - - 16. OXY-ACETYLENE WELDING 134 - - 17. LEAD-BURNING 150 - - INDEX 155 - - - - -SOLDERING, BRAZING AND WELDING - - - - -CHAPTER I - -The Various Processes of Joining Metals - - -Apart from the use of rivets, screws, etc., metal is commonly joined by -soldering, brazing, or welding, three groups of processes that have one -thing in common--the use of heat to fuse either the metals themselves or -an alloy which is interposed to consolidate the joint. The word “solder” -is derived through the French from a Latin word meaning “solid.” - -Soldering may be “soft” or “hard.” Soft-soldering uses lead-tin alloys -which are easily melted in a bunsen gas flame or with a hot iron or bit; -while hard-soldering employs a silver-copper alloy, to melt which a -mouth blowpipe at least is necessary. Brazing is hard-soldering with -spelter (brass), and a forge or a heavy blowlamp or a powerful blowpipe -must be employed to provide the heat. - -Welding is a fusion process which in the past was almost entirely -confined to wrought-iron and steel, these metals possessing the property -of weldability to an extent unknown in the case of any other metals. -The blacksmith’s process of welding is to heat the iron or steel until -the surface of the metal becomes pasty, and then to bring the two pieces -into intimate contact by hammering on the anvil. Of late years the -welding of iron, steel, copper and some other metals has been rendered -possible by the use of certain electrical and chemical methods and--most -important of all--by the use of the oxy-acetylene blowpipe, the process -being known as “fusion welding” or “autogenous soldering,” the word -autogenous implying that the process is complete in itself and -independent of the use of any extraneous substance such as solder. The -thermit process, of which so much has been heard, and which is briefly -dealt with later, is the fusion welding of iron and steel by means of -the intense heat produced by the combustion of a special chemical -compound. Perhaps the oldest of the autogenous soldering processes is -“lead-burning,” in which the flame of an airo-hydrogen blowpipe is -brought to bear upon the lead, the joint being fed with a strip of the -same metal. - -Soft-soldering is an operation that the beginner will not find nearly so -difficult as hard-soldering or brazing, and although the strength of -joints made by it is not nearly equal to that produced by the methods -named, it fills a useful place within its scope. It is purely a surface -union--that is, the solder adheres to the faces in contact in much the -same manner as an adhesive sticks to metal; but with the assistance of -fluxes, the contact is made so intimate that some force is necessary to -break the joint. Soft-soldering is also of use where brazing would -simply mean the ruin or destruction of the metals, as in the cases of -lead, poor-quality brass, pewter, tin, zinc, and in tinplate and -galvanised iron. - -In silver-soldering and brazing, the silver or spelter that fuses to -form the joint alloys itself so intimately with the copper or brass that -it actually becomes part of the piece itself, and for all practical -purposes cannot be distinguished from it. But soft-soldering is not -always inferior to hard-soldering. Indeed, the surface nature of the -soldering often constitutes its value. - -The strongest joints of all are produced by fusion welding, as will be -duly understood from later chapters. - - - - -CHAPTER II - -Soft Solders - - -A solder should melt at a slightly lower temperature than the metals -which it unites, and should possess the quality of alloying with the two -surfaces, thus effecting a sound and true metallic joint. Ordinary soft -solders are lead-tin alloys, and the larger the proportion of lead the -commoner is the solder said to be. At an extreme is plumber’s solder, -consisting of 2 parts of lead to 1 part of tin, and, at the other, the -best blowpipe soft solder, which contains 2 parts of tin to only 1 part -of lead. In the ordinary way, a “coarse” or “common” solder is 2 parts -of lead to 1 part of tin; a “fine” or “medium” solder, 1 part of lead to -1 part of tin; and a “very fine” or “best” solder, 1 part of lead to 2 -parts of tin. - - -=Eutectic Alloys.=--Lead-tin solders are eutectic alloys--that is, they -are examples of the phenomenon of a combination of two metals melting at -a temperature lower than one of them would if melted separately. Thus, -lead melts at about 328° C., and tin at about 232° C., yet reference to -the following table, given by Mr. A. H. Hiorns, will show that the -“commonest” solder mentioned fuses at 303° C., and the “best” at 175° -C. - -_Melting points of lead-tin alloys_ - - _Tin %_ _Lead %_ _Melting_ - _point (C.)_ - 10 90 303° - 20 80 278° - 30 70 255° - 40 60 230° - 50 50 205° - 60 40 187° - 63 37 175° - 70 30 185° - 80 20 198° - 90 10 215° - - -=Hardness of Solders.=--According to the before-mentioned authority, -Saposhniko, in 1908, determined the hardness of various lead-tin alloys -by Brineli’s method, by which a steel cone is forced into the metal. The -results he obtained are as follow: - - Lead 100 90 80 70 60 50 40 - Tin 0 10 20 30 40 50 60 - Hardness 3·9 10·1 12·16 14·5 15·8 15·0 14·6 - - Lead 34 33 32 30 20 10 0 - Tin 66 67 68 70 80 90 100 - Hardness 16·7 15·4 14·6 15·8 15·2 13·3 4·1 - -These results, says Mr. Hiorns, show that the hardest alloy is the one -with 66% (about 2 parts) of tin and 34% (about 1 part) of lead, which -also is the one having the lowest melting point of all the lead-tin -alloys. The results also show that tin is slightly harder than lead. - - -=Compositions of Soft Solders.=--As already shown, solders vary in -fusibility according to their composition, and the choice should be -determined by the nature of the work and the properties of the metal to -be soldered. Should a solder be used of too high a melting-point, the -metal will itself be fused before the solder begins to flow. - -A point to be particularly observed is that the introduction of a -foreign substance into the solder--for example, the addition of a little -zinc to a pot of “very fine” solder--will utterly spoil it and render it -unworkable. To remove zinc from solder, melt the solder in a pot, take -it off the fire and stir in powdered sulphur or brimstone until the -whole is of the consistency of wet sand. Replace the pot on the fire and -melt, but do not stir the contents. The sulphur and zinc will rise to -the surface and form into a cake. Now take the pot off the fire and -carefully remove the cake without breaking by employing two pieces of -hoop iron with bent ends. - -It is false economy to use a rough solder for fine work on the score of -cheapness, since more solder is required for a given job on account of -the rough particles of solder clinging to the work; moreover, the rough -appearance of the soldering may completely spoil the job. - -The table on the opposite page gives the fluxes and the compositions of -soft solders suited to a number of different metals. - - -=Making Solder Strips, Wire, Tears, etc.=--Only clean, pure tin and pure -lead should be employed. The lead is first melted and then the tin -added. When all is melted, place a piece of resin on the molten metal -to act as a flux, and after well stirring, the solder is made into -strips by pouring from a ladle. Solder should not be poured into sand. -It may be poured into strips on an oiled sheet of black iron, preferably -corrugated to accommodate the strips. In the absence of a corrugated -iron sheet, some workers use a ladle resembling a large spoon with a -hole about 1/16 in. in diameter near the end. To form the strips, get a -ladle full of solder, place it on a flat iron sheet; then, tilting the -ladle to allow the solder to flow over the hole, quickly draw the ladle -across the sheet. A thin strip of solder should thus be formed, and the -thickness of the strip may be varied by increasing or decreasing the -diameter of the hole in the ladle. A button of solder usually forms at -one or both ends of the strip, and this excess should be melted off the -strips by just dipping the ends into the molten solder in the pot. - -SOFT SOLDERS FOR VARIOUS METALS - - ----------------+--------------------------+-------------------------- - | | _Soft Solder_ - | +------+------+------------ - _Metal to be | _Flux_ | | | _Other - soldered_ | |_Tin_ |_Lead_| constit- - | | | | uents_ - ----------------+--------------------------+------+------+------------ - Aluminium | stearin | _see table on p. 59_ - Brass { |[1]zinc chloride, resin { | 66 | 34 | - Gunmetal { | or ammonium { | 63 | 37 | - Copper { | chloride { | 60 | 40 | - Lead | tallow or resin | 33 | 67 | - Block tin | zinc chloride | 99 | 1 | - Tinplate | zinc chloride or resin | 64 | 36 | - Galvanised steel| hydrochloric acid | 58 | 42 | - Zinc | hydrochloric acid | 55 | 45 | - Pewter | gallipoli oil | 25 | 25 | bismuth, 50 - Iron and steel | ammonium chloride | 50 | 50 | - Britannia metal | tallow or resin | 25 | 25 | bismuth, 50 - Gold | zinc chloride | 67 | 33 | - Silver | zinc chloride | 67 | 33 | - Bismuth | zinc chloride | 33 | 33 | bismuth, 34 - ----------------+--------------------------+------+------+------------ - - [Footnote 1: Zinc chloride is the ordinary “killed spirits.”] - -Solder wire is very handy for small work, and can be made in the -following way: Roll a sheet of stiff writing or drawing paper into a -conical form, rather broad in comparison with its length; make a ring of -stiff wire to hold it in, attaching a suitable handle to the ring. The -point of the cone should first of all be cut off to leave an orifice of -the size required. It should then be filled with molten solder, and held -above a pail of cold water, and the stream of solder flowing from the -cone will solidify as it runs and form the wire. If held a little -higher, so that the stream of solder breaks into drops before striking -the water, it will form handy elongated “tears” of metal; when it is -held still higher, each drop forms a thin concave cup or shell, and each -of these forms will be found to have its own peculiar uses in blowpipe -work. - -The method adopted for granulating tinman’s solder, which is very rarely -called for, is as follows: Place a piece of wood, well greased, over a -tub containing water, and by gently pouring the molten alloy from a -distance in a small stream on to the greased board, the metal is broken -up into a large number of very fine shots, which run off the board into -the water and are immediately cooled. The fine shots are then taken -from the water and gently dried. - - -=Making Solder from Pewter.=--This alloy is composed of variable -proportions of tin and lead, the average composition being about 4 parts -of lead to 1 part of tin. If old pewter is to be utilised for making -solder, tin will have to be added to the molten pewter. Thus, to convert -5 lb. of average pewter to “coarse” or “common” solder, add 1 lb. of -tin; to “fine” or “medium,” add 3 lb. of tin; and to “very fine” or -“best,” add 7 lb. of tin. The respective proportions of lead and tin -will then be 2 and 1; 1 and 1; and 1 and 2. After the proper quantity of -tin has been added, mix some powdered sal-ammoniac with the molten -metals, and well stir the alloy; it is then ready for pouring into the -moulds. - - -=Making Coarse Solder from Composition Piping.=--Good composition piping -is made of nearly all tin, or an alloy of tin and lead, in which the -former metal is in excess, and formerly was much used by plumbers in the -making of coarse solder, as the material consisted of odd pieces of -small value. As, however, a great deal of composition tubing is made out -of old metals of which lead, tin, antimony, arsenic, and zinc form the -alloy, it is not advisable to introduce it into solder. Should it be -done, the melting point of the solder would be raised, and in applying -it to the lead to be joined together, would probably partly melt it. -Neither do the metals named alloy in a thorough manner, but partake more -of the nature of a mixture in which the constituents partly separate -when making the joints, and some, especially zinc, show as small bright -lumps on the surface. Joints wiped with what is usually called “poisoned -metal” are difficult to make, almost invariably leak when on water -service pipes, and are dirty grey, instead of bright and clean. The zinc -could be removed from the mixture by the method already given. - - -=Combined Solder and Flux.=--This consisted of equal parts of lead and -tin made into fine tubing and afterwards filled with flux having resin -as a base. “Tinol” is a paste made of finely powdered solder and a -special flux, and there is also “Tinol wire” having a core of flux. - -A “magic” solder, sold by hawkers, consists of the above tubular -flux-filled solder of such low melting point that it can be fused in the -flame of a lighted match. - - -=Soft Solders that Melt in Boiling Water.=--The following soft solders -melt at a temperature lower than that of boiling water: 1 part tin, 1 -part lead, and 2 parts bismuth, melting point about 200° F.; 8 parts -lead, 4 parts tin, 15 parts bismuth, and 3 parts cadmium, melting point -140° to 150° F.; 6 parts lead, 7 parts bismuth, and 1 part cadmium, -melting point about 180° F. To ensure the alloys melting at the -temperatures stated, the metals of which they are formed should be free -from impurities, and care should be taken to prevent oxidation while -making the alloys. When melting the metals, that having the highest -melting point should be melted first, with a layer of resin over it, the -other metals being added in the order of their melting points. The alloy -should then be well stirred with a wooden stick, and poured quickly into -moulds. - - -=Re-melting and Overheating Solder.=--After solder has been re-melted a -number of times or has been overheated, its content of tin will be -reduced, and the solder will become poorer and coarser. The tin melts -earlier than the lead and, being the lighter of the two, floats over it, -and is thus fully exposed to the air, the oxidising effect of which on -heated, molten metal is extremely active. The oxidised tin forms a -dross, from which most of the tin may, however, be recovered by melting -it with powdered charcoal, which combines with the oxygen and frees the -tin. The addition of a little fresh tin is desirable. - - - - -CHAPTER III - -Fluxes Used in Soft-soldering - - -=Why a Flux is Required.=--The great essential to successful soldering -is the chemical cleanliness of the surfaces to be united, and the proper -use of a flux. Although work may be filed or scraped perfectly bright -and clean, this is not the kind of cleanliness which is alone -sufficient; there is always in course of formation a film of oxide -present, and the duty of the flux is to dissolve this and keep any more -from forming. Then, and not until then, will the molten solder “run” and -spread over faces in the intimate contact necessary. If this vital -precaution of cleaning and fluxing is always observed, the difficulties -which many beginners experience in effective soldering will vanish. - - -=Variety of Fluxes.=--There are a good many fluxes employed, including -tallow (largely used for lead and pewter), resin (used for lead, -compo-pipe, and tinned metals), hydrochloric acid, diluted (for zinc and -galvanised iron), and chloride of zinc (the well-known “killed spirit”). -The last-named is the most generally used, being suitable for tinplate, -tinned iron, new zinc, copper, and brass. Sal-ammoniac is also utilised, -sometimes in conjunction with chloride of zinc. The small worker who -does but a moderate amount of soldering will find it convenient to use a -soldering paste such as “Fluxite,” which is sold in a tin, and can be -kept handy and applied to the work with a sliver of wood. “Tinol” is a -paste flux in combination with a solder. - - -=Preparing Zinc Chloride (“Killed Spirit”).=--Make this flux at home -from finely snipped new sheet-zinc and _pure_ hydrochloric or muriatic -acid. (This is sufficiently cheap at any working druggist’s stores, and -infinitely preferable to the contaminated oil-shop quality known as -“spirits of salt.”) Stand the acid outdoors in a stoneware crock, add -the zinc cuttings a few at a time at first, and when the first violent -ebullition moderates, put in the rest. Be sure to provide an excess of -metallic zinc, observing that a quantity remains undissolved after all -chemical action ceases. Leave the metal in the liquor for twelve hours -(covering the crock with a pane of glass), then decant and filter into a -wide-mouth glass jar of handy size. _Do not add water_ to the -concentrated zinc chloride solution; dilution is sometimes recommended, -but should never be done; the heavy, slightly syrupy, water-bright -liquor should be used as it is. The alleged “cleaning” qualities of this -chloride can scarcely be admitted to exist, and its principal function -is to shield the surfaces of the work from oxidation; this it fulfils by -the formation of a viscid glaze on the heated metal when the salt -reaches its anhydrous (waterless) condition by evaporation. The addition -of water to the flux, therefore, only uselessly prolongs the period -occupied by evaporation, and wastes heat. - -Always remove all trace of flux from finished work, first by soaking in -water, and afterwards by washing with soda, soap, and water. Otherwise, -there is the risk of the work being corroded. - -Special “soldering solutions,” obtainable ready prepared, should not be -used in preference to zinc chloride made as before explained or to the -well-known paste fluxes. - - -=Applying the Flux.=--A short heavy bottle about 3 in. or 4 in. high is -best for bench use as a flux container. It should be particularly noted -that soldering and soldering tackle should be kept as far away from -other work (and iron and steel goods and tools) as possible. - -A pointed wooden stick is not a good tool for applying killed spirit, -because the acid acts on the wood, which becomes unpleasant to handle, -and the liquid does not leave the wood readily enough to place the right -quantity on the exact spot to be soldered. A galvanised iron wire is -better. Another good tool is a thin steel or iron “spit,” about 12 in. -long, and a steel knitting-needle is also excellent. Should a brush be -preferred, take a few hairs from a broom, place them in one end of a -thin metal tube, and then flatten the end with a blow from a hammer. - -A brush made by hammering the ends of a short length of cane until the -fibres are like bristles is frequently used for the purpose, the handle -end being soaked in molten wax before using the cane brush the first -time. - -[Illustration: Fig. 1.--Wire for Applying Flux] - -A convenient method of applying liquid flux is to have a bottle with a -screw cap sprinkling top such as is often used for perfumes, and to push -a length of thick galvanised iron wire through the orifice in the -stopper, leaving about 1-1/2 in. projecting above. The lower end should -just reach the bottom of the bottle, and may be flattened and pointed. -The lead nipple is squeezed round the wire to hold it firmly, and the -projecting end bent into a ring to form a handle, as shown in Fig. 1. -The cork part should be thinned a little to render it an easy fit in the -bottle neck. The flux can be quickly applied with the wire exactly where -it is wanted, and in very small quantity; for a long seam the wire can -be run along with one dip in the solution. The fingers need not be -brought into contact with the flux; the cork will not go soft and will -not sink down owing to the lead flange supporting it. - - -=Flux Used on Food Containers.=--Killed spirits is objectionable as a -flux for soldering vessels intended to contain food of any kind. Not -only is this flux a poison, but it is liable to produce subsequent -rusting wherever used unless all traces of it are thoroughly removed -immediately after soldering. A good non-poisonous flux suitable for tin -boxes may be made by dissolving resin in oil. Place a quantity of -powdered resin in an iron vessel, add colza, olive, or any similar oil, -and apply gentle heat, meanwhile stirring it until the resin is -dissolved. Dissolve as much resin in the oil as possible without making -the flux too thick (when cold) to apply with a brush. One or two small -experiments will soon decide the required proportions. The resin is -really the base of the flux; but the oil is added to facilitate its -application and removal before and after the soldering process. - - - - -CHAPTER IV - -Soft-soldering with the Copper Bit - - -=Choice between Blowpipe and Bit.=--The method of heating depends on the -size of the work, or rather the area to be soldered, and the -conveniences at the command of the worker. The soldering bit, although -so commonly used, is not necessarily the best for the beginner to use -for small work. A blowpipe flame--from a bunsen burner or a spirit -lamp--is far more convenient and neat, and its effects can be applied -and localised with the greatest precision, down to the merest pin point -of heat applied at a definite spot. The bit is chiefly useful for long -joints such as in tinplate work, and for pieces bound together to which -the bit is applied to heat up and melt solder between them. But for work -where the soldering area does not measure more than an inch or so (and -there is a vast amount of this kind), the blowpipe flame is far -preferable. It must be admitted, though, that this is a matter in which -some workmen might have two distinct opinions; and, as already remarked, -the bit is far more commonly used. - -[Illustration: Fig. 2.--Soldering Bit] - -[Illustration: Fig. 3.--Pivoted Soldering Bit] - - -=Copper Bits.=--The soldering bit or bolt (miscalled an “iron”) carries -a pointed lump of copper at the end (Fig. 2), riveted in, or -alternatively, in small sizes, screwed on to the shank. Some bits are -pivoted (see Fig. 3) to enable them to point at various angles for -dealing with difficult situations. - -A home-made bit (Figs. 4 and 5) may be made by drilling and tapping a -short length of 1-1/2-in. or 2-in. square copper to receive the screwed -end of a rod of 5/16-in. iron, the copper being afterwards heated and -drawn to a point or to a blunt edge as preferred. This forms a good bit -for most ordinary purposes. An axe-head or hatchet bit is shown in Fig. -6; the copper bolt is riveted in the eye of the iron rod, the bit, -however, being free to revolve, as this is essential when making joints -in heavy lead pipe, for which purpose it is principally used. Fig. 5 -represents a bit which is a combination and modification of the two -others, and it is largely used for the internal soldering of bottoms of -large drums, milk churns, etc., where great local heat is required. - -[Illustration: Fig. 4.--Home-made Soldering Bit] - -[Illustration: Fig. 5.--Bit for Internal Soldering, etc.] - -[Illustration: Fig. 6.--Hatchet Soldering Bit] - -As to the size of bit required, for ordinary small work the straight -type should not be less than 8 oz. or 10 oz. (weight of the actual -copper). - -Two bits are very useful in doing a large job, as the work can then be -arranged to progress continuously, one bit heating while the other is in -use. - -A bit suitable for quite light work can be easily made by drilling and -tapping a piece of copper, say 1/2 in. by 1/2 in. by 1-1/2 in. long, -either in the end or in the side, for a 3/16-in. steel rod 12 in. long, -a handle being then fitted at the other end. - -In the “Tinol” telescopic soldering bit for amateurs’ use, the handle is -in three parts: (_a_) the actual wooden handle bushed with metal, and -provided with a set-screw shaped like a screw eye, and therefore easily -turned; (_b_) a steel tube which telescopes into the first part, and -which is also provided with a set-screw; and (_c_) a short rod, having -at one end a hatchet-shaped copper bit. The extreme length of the tool -is 12 in., and the length, when the parts are telescoped together, is -about 5 in. - -The “Fluxite” bit is larger and heavier. It has a hollow cast-iron -handle, perforated to dissipate the heat, threaded internally at one end -to receive the screwed end of the iron stem, only 5 in. or so in length, -which at the other end screws into an adapter or holder which, in turn, -receives the screwed end of the copper bolt, itself about 4 in. long. -The bit is taken to pieces in a few moments, and is quite a workmanlike -tool. - -[Illustration: Fig. 7.--Spirit-heated Bit] - - -=Spirit-Heated Soldering Bits.=--Bits heated by benzoline or spirit may -be made with a small barrel-shaped reservoir which also forms the -handle. One end of the reservoir is fitted with a filling cap, and from -the opposite end protrudes the tube carrying the burner. To the tube end -of the reservoir an iron clip is attached, and this secures an iron bar -which stands out over the burner head. At the end of this bar the copper -bit is attached and held either vertically or horizontally in the -flame. Tool merchants’ catalogues show a variety of such implements. -Fig. 7 illustrates one of the most elaborate of them all, the weight -complete being 2-1/4 lb. It has a polished brass container A, of 1/5 -pint capacity--sufficient for 45 to 60 minutes, whence the benzoline -flows to the burner B, the flame from which heats the copper bit C. This -bit may be of any of the regular shapes, and weighs about 1/2 lb. The -position shown is that for heating the bit preparatory to soldering. The -tray D catches any drips that might occur at starting, E is the stand, F -the filler cap, G is the regulating handle, and H is the clamp that -holds the bit in place. - -[Illustration: Fig. 8.--Bit attached to Blow-lamp] - -[Illustration: Fig. 9.--Gas-heated Bit] - -A writer in _Popular Mechanics_ has stated that the ordinary blow-lamp, -with the burner end equipped with a copper bolt (see Fig. 8), makes an -excellent soldering device. The point can be easily kept at the proper -heat, and there will be no want for hot coppers. The end of the burner -is threaded on the outside, and a hole is drilled in the copper point -and threaded to match. Small holes are drilled in the copper in the same -manner as in the burner, to make vents for the flame. - - -=Gas-heated Bits.=--These are largely used in factories, and are -cleanly, expeditious, safe, and convenient. The type shown by Fig. 9 is -very handy, and the illustration and description are due to F. X. -Sommers, Jun., in the _American Machinist_. A mixture of air and gas -enters the pipe at about 10 lb. pressure, or enough to give a hot, blue -flame. The part A is of cast-iron, which, on experiment, has been found -to last longer without corroding than steel, although copper would be -better. The soldering bolt B was made of steel because it kept the -correct shape point much longer than cast-iron or copper, although the -latter metal is better for transmitting the heat. The point should be -tinned before using. This form of soldering head is being used on -automatic can-soldering machines, and does the work effectively. It also -saves gas. It will heat to the correct temperature in about 1-1/2 -minutes. - -[Illustration: Fig. 10.--Gas-heated Bit complete] - -[Illustration: Fig. 11.--Air Inlets in End of Air Chamber] - -[Illustration: Fig. 12.--Section through Air Chamber and Gas-reducing -Valve] - -[Illustration: Fig. 13.--Details of Cones or Needles] - -A gas-heated bit invented by W. G. Ryan is shown in Figs. 10 to 13. The -actual bit A is held in a steel sheath B having a space underneath the -bit to allow the gas to pass. The sheath has a row of holes on each side -to allow the gas to come through, the flame enveloping the bit when in -use. The gas, supplied through a flexible tube, passes through the tube -that forms the handle, at the end of which is a small chamber C to admit -air, which mixes with the gas to cause it to burn atmospherically, the -supply of gas passing through a small cone valve D and thence through -the air chamber. In the air-inlet holes E at the end of the air chamber -are fitted small cones F to regulate the quantity of air. All the cones, -including the gas-valve cone, are connected rigidly together, so that -when cutting down the gas supply temporarily, the air supply is -automatically reduced, and the gas flame remains in being, although its -size is much reduced. It has been found that, in some gas-heated bits, -the cutting down of the gas seriously interferes with the proportion of -the gas and air mixture, resulting in a back-fire. The device here -described has been invented especially to obviate that trouble. To -reduce the gas supply and, with it, the air supply also, all that is -necessary is a slight forward movement of the fitting to which the cones -or needles are attached. The copper bit is kept in position by the -sheath or clip, the small bolt in which can be taken out in a moment -when special attention to the bit becomes necessary. The connection to -the flexible gas tubing is at G, while H indicates a guide and stuffing -box for the gas-valve cone or needle. - -[Illustration: Fig. 14.--Gas-stove for Heating Bits] - - -=Stoves for Heating Soldering Bits.=--Although a copper bit may be -heated in any fire, it is better to avoid the dirt, smoke and tarry -stickiness which are often present in a coal fire. In the absence of -gas, a bright, clear coke fire or a charcoal fire should be used -whenever available. Portable oil stoves of the wickless type can also be -employed, but the ideal fuel is gas, which may be regulated at will to -give a uniform temperature. Two gas-stoves specially constructed for -copper bits are shown by Figs. 14 and 15. - -[Illustration: Fig. 15.--Gas-stove for Heating Bits] - - -=Tinning a Bit.=--Before a bit can be used, it must be “tinned,” that -is, coated with solder in a smooth complete covering, for which -purpose--by one method, not the best, but the most general--the end is -heated to a dull red, rubbed quickly with the file on the facets, dipped -in killed spirit or “fluxite,” or rubbed against a piece of -sal-ammoniac, and then applied to a stick or lump of solder, the facets -being quickly wiped or rubbed on a piece of tinplate so as to spread the -solder evenly. When properly done, the nose of the bit is coated with a -smooth film of solder. This must always remain so, or the bit will not -act, and when it is honeycombed, or the “tinning” is present in patches, -it must be re-tinned. A bit must never be raised to a red heat -sufficient to melt the tinning. The bit does not operate well at such a -heat, because its contact makes solder too fluid and apt to run too -quickly. - -When dipping a hot bit, prepared for tinning, into killed spirit, a -sharp pop, without smoke or spluttering, denotes the right temperature. -If, on withdrawing the bit, it is damp and still unclean, it had not -been heated sufficiently. - -Another method of tinning may be mentioned. Into a small and clean tin -box (a 2-oz. tobacco tin about 3/4 in. deep) put some scraps of solder -and powdered resin. Heat the bit to a very dull red, quickly file up -clean on one side of the point, and then plunge into the solder and -resin and rub about; it will at once take on a coat of the alloy. A -second side of the bit may be tinned by then repeating the operation, -re-heating if necessary. The bottom of the box should be covered with -solder, which adheres easily enough, with a film of resin on top. It is -probably most convenient to tin the under side and the left-hand working -face of the bit. “Tinol” could be used in this way without admixture -with anything. - -Still another method is to use a firebrick having a hollow in which the -solder and resin are placed; but the tin box plan is thought to be -better. - -Undoubtedly the best method of tinning a bit is that in use by the -plumber who well knows the invaluable qualities of sal-ammoniac -(ammonium chloride) for the purpose. He has no wish to squander energy -on those vigorous rubbings of the bit--on paving-stone, bath brick, -tinplate, etc. etc., and he believes that the habit of dipping the bit -into zinc chloride is both slovenly and wasteful, for not only is this -corrosive stuff sprayed about broadcast, but the remainder is soon -rendered unfit for its purpose by contamination with copper chloride and -dirt from the fire. The outlay of a few halfpence on a sizable slab of -sal-ammoniac will keep the bit in the best condition for years, and save -hours of superfluous labour. Commercial sal-ammoniac is obtainable in -large, rugged crystals of a tough, fibrous texture. A piece weighing -upwards of 1/4 lb. can be trimmed to a roughly rectangular slab, a few -inches long and wide and about 1 in. thick; and a cavity should be -scooped in one of the flat sides to accommodate the bit. - -[Illustration: Fig. 16.--Tinning Bit in Sal-ammoniac Block] - -Let the bit-faces be made shapely and filed bright and the tool -thoroughly heated in a clean fire, removed, flicked free of ash, and -then held down firmly in the cavity of the sal-ammoniac block (see Fig. -16). Profuse white fumes will arise, and the surface of the salt will -fuse. Bear heavily on each facet in turn, and then melt a few beads of -solder into the cavity along with the bit, and the latter will become -brightly tinned in a moment or so. The bit should be applied to the -“ammonia block” every few heats, or as required, as the work progresses, -and flicked with a tuft of dampened cotton-waste. - -The sal-ammoniac has one great disadvantage--it is deliquescent -(collecting moisture from a damp atmosphere), and its near proximity to -most metals oxidises and corrodes them. Iron and steel, particularly, it -rusts rapidly and deeply. Therefore the tools (saw and chisel) used to -shape the block must be washed, dried, warmed, and greased before they -are laid by, and the waste fragments must be carefully swept up and -disposed of. The block itself must always be kept apart from tools. -Plumbers enclose it in a sheet-lead box wrapped in a greasy rag; -amateurs may store it on a dry shelf, parcelled in waxed paper secured -by a rubber band, or in a length of motor-tyre inner tube, rolled up. - - -=Simple Soldering.=--Scrupulous cleanliness in everything connected with -the process of soldering is essential to success. The ordinary procedure -in making a joint is to clean the surfaces first by filing or scraping -with a scraper or a knife or a plumber’s shave-hook (Fig. 17). In some -cases, dirty metal is cleansed with dilute hydrochloric acid. With or -without preliminary heating of the work, flux is then applied to the -joint, and the heated bit is held in one hand and a stick of solder in -the other, and the stick drawn along the joint while the bit touches it -(or “drops” of solder may be transferred to the work by means of the -bit). This will cause a line of molten solder to run, and some skill and -care are necessary to get just the right amount of solder without -wasting it and allowing it to spread in a lumpy fashion beyond the -necessary area. The bit is next worked up and down the joint to spread -the solder, and by the transmitted heat to make it thoroughly penetrate -the joint. This is an outline of the process, and there is a number of -points requiring special instruction or a few words of caution. - -[Illustration: Fig. 17.--Shave-hook] - -Note that the work must be filed, scraped, or otherwise mechanically -cleaned, and then chemically cleaned by coating with the flux just where -the soldering is required. In heating the copper bit do not let it reach -even a dull red heat. Lightly dip it into the flux to clean the point; -then, with a small button or blob of solder resting on the work, place -the bit momentarily upon it to cause the solder to flow, and draw the -bit where the solder is required. - -Many beginners try to draw along the solder with an insufficiently -heated bit. The result is a series of lumps--“putting it on with a -trowel,” as it is sometimes termed. A good joint cannot be made this -way, however much solder may be used. - -Some beginners fly to the other extreme, and try to make a neat job with -a red-hot bit, which results in the solder assuming a sandy appearance -and in the work being discoloured. - -Others try to solder uphill--that is, they hold or place the work in -such a way as to cause the solder to flow away from where it is -required. The correct method is to solder downhill by tilting or -inclining the work, so that the solder will always collect around and -travel with the point of the bit. This, besides facilitating the work, -makes a strong joint, and imparts a clean and neat appearance to the -job. - -[Illustration: Figs. 18 and 19.--Incorrect and Correct Methods of -Holding Bit] - -A common mistake is to hold the bit in a cramped and awkward way, as in -Fig. 18, the hand being twisted under the handle, the thumb being -brought to the top, and the elbow forced to the side. The correct -positions of arm and fingers are shown in Fig. 19; the elbow is held -well out from the body, and the thumb is placed directly under the -handle of the bit, forming a fulcrum over which the bit may be slightly -raised or depressed at will. This is all-important when soldering very -fusible metals such as pewter, tin, etc., on which the weight of the -copper bit should never be allowed to rest, as otherwise a hole will -suddenly be made in the work. The whole weight of the bit should be -supported and balanced on the thumb by the downward pressure of that -part of the hand close to the little finger. The worker should not for a -moment lose control of the copper bit, and control is always assured -when the thumb is underneath the handle. - -There is but little strength in a butt joint with the edges of the metal -only just touching--that is, without a lap; to take the example of a -small cylinder, the body seam should have at least a 1/4-in. lap. Fig. -20 represents an example of internal grooved seam soldering, which may -be executed in the following way:--After applying the flux, place a -small button of solder inside the cylinder on the seam, rest the bit -momentarily on the solder to melt it, and then draw it gently along the -seam. The cylinder should be slightly tilted to allow of the solder -travelling with the point of the bit. The hand should avoid touching any -part of the work that comes directly into contact with the copper bit, -as otherwise the hand would be badly burned. - -[Illustration: Fig. 20.--Soldering Internal Grooved Seam] - -[Illustration: Fig. 21.--Soldering on Can Bottom Internally] - -The method of internally soldering the bottom on a canister, etc., is -shown in Fig. 21. The bottom is held in position by gently pressing it -against (but not placing it on) the bench during the soldering process, -while the tilt of the canister and the position of the bit cause the -solder to travel with the bit. - -In soldering all such articles, the soldering should be done with one -sweep of the bit, the left hand meanwhile making the necessary -revolution. This saves time and solder, and avoids the unsightly -appearance of a series of starts and stops. - -In work of a larger and more substantial nature, as, for example, -galvanised or tinned iron work, the bottom of the article is first -“knocked up,” and then soldered internally. Fig. 21 represents an -example of internal soldering where the whole weight of the bit is shown -resting on the molten solder inside; this provides the local heat -required to “sweat” the solder into the four thicknesses of metal which -constitute the bottom seam; and for this work the bottoming bit shown in -Fig. 3 is often used. Pewter, lead, zinc and tin--the latter should not -be confused with tinplate--do not require sweating, on account of their -low fusibility, and any attempt even to solder them with a very hot bit -will probably end disastrously. - -[Illustration: Fig. 22.--Soldering Can Externally] - -Fig. 22 shows an example of external seam soldering. The method there -shown is invariably adopted for simple lap seams, although grooved seams -are similarly soldered. A grooved seam, however, should preferably be -soldered internally. The position of the worker’s elbow and thumb should -be noted, as should also the tilt of the cylinder (more pronounced in -this case than the other) in order to secure the downflow of the solder. - -Sweating has already been mentioned. It should be said that one of the -easiest ways in which a beginner may make a reliable joint is to prepare -both faces of the joint by fluxing and covering with a thin film of -solder, and then pressing the two parts together with the hot bit until -the top part “floats” and then settles down. The advantage of this way -is that one can be sure of perfect application of the solder to the -joint faces, since each is dealt with first and thoroughly coated, with -no faulty patches. Sweating is also done in the flame of a bunsen burner -or blowpipe, as explained later. - - -=Reinforced and Filled-in Soldered Joints.=--The bottoms of square or -cylindrical vessels should, preferably, be soldered from the inside, and -“buttons” of solder may be melted to assume a stout triangular-shape -stud in the corners of the square vessels. A tinned rivet is sometimes -riveted or just placed in a corner, and sufficient solder floated over -it to strengthen the corner. Solder is always liable to run through an -improperly closed seam at the corner when external soldering is resorted -to; but in cases where this is the only practical method, a tinned rivet -may be inserted from the outside, and then soldered over. It sometimes -happens that two “raw” edges require soldering together without a lap. -Where a strong joint is required a good plan is to place a length of -tinned wire over both edges and solder the lot together. In addition to -strengthening the joint, the wire considerably improves the general -appearance. A simpler joint may be made by “skimming” the solder over -with a copper bit heated only just sufficiently to melt the solder. The -quick and skilful touch is required to perform this operation -satisfactorily; but a little practice will soon bring the necessary -proficiency. The idea is to “draw” the solder across the joint quickly, -before it has time to run through. This method is useful when soldering -thin metal goods of a lower degree of fusibility than that of the solder -employed. No preparation for filling cracks previous to soldering can be -recommended, beyond such small pieces of metal that may be afterwards -soldered over and effectively hidden. It is much better to endeavour to -produce work of such quality that this expedient is altogether -unnecessary. - - -=Soldering Heavy Milk Churns.=--When soldering the bottom rims on large -milk churns, sufficient heat cannot be maintained with only one -soldering bit. At least two heavy bits are required, so that one may be -getting hot while the other is in use. The rims are usually tinned -before being fixed by first pickling them in dilute hydrochloric acid, -washing, and then dipping in a bath of molten tin. When repairing and -resoldering the rims, remove all dirt and rust with a file, use a few -brushfuls of raw spirits further to assist the cleaning process, then -wash with clean water and solder in the usual way, using killed spirits -as a flux. - - -=Soldering Hole in Enamelled Ware.=--First scrape or file away the -enamel quite clear all round the hole, apply a little raw spirit to the -surface of the iron, and coat it with solder in the usual manner. Then -cut out a tin disc large enough to cover the hole, and solder this in, -using killed spirit as the flux. - - -=Soldering Leaded Lights.=--For soldering the calmes of a lead-light -window, the calmes having been fitted properly together, shave a small -round dot at the point of junction, sprinkle a little powdered resin on -the shaving, and with a copper bit or with a glazier’s iron having a -tinned face, melt a small piece of tinman’s ordinary solder on the -shaved part so that it tins to the lead and forms a round button. - - -=Soldering Catch on Gun-barrel.=--In soldering a catch on a gun barrel -it will first be necessary to tin both barrel and catch, and then to -wire them together, in addition binding the barrels for some distance -from each side of the catch, making the ribs secure with wedges. To melt -the solder, use heaters; these are generally made of copper with iron -handles; or iron rods can be used, the ends being made red hot and -inserted in the barrels. Cut some small slips of thin solder and place -them on each side of the catch, using powdered resin. As soon as the -solder melts, remove the heaters and cool the barrels. - -[Illustration: Fig. 23.--Mouth Blowpipe] - -[Illustration: Fig. 24.--Black’s Mouth Blowpipe] - -[Illustration: Fig. 25.--Fletcher’s Mouth Blowpipe] - -[Illustration: Fig. 26.--Section through Blowpipe Flame] - - - - -CHAPTER V - -Soft-soldering with Blowpipe or Bunsen Burner - - -=The Mouth Blowpipe.=--Although soft-soldering is usually associated -with the use of a copper bit, quite a number of jobs can be done without -one, using instead a bunsen burner or, more generally, a mouth blowpipe, -which is an inexpensive appliance, useful for both hard and soft -soldering, and with either gas, candle, or a methylated-spirit flame. -Three shapes of mouth blowpipe are shown in Figs. 23 to 25. In a -blowpipe flame there are three cones, X, Y, Z (Fig. 26). X is a -non-luminous cone, consisting of a mixture of atmospheric air and -unburnt combustible gases (each with a low temperature); Y is a luminous -cone, composed of burning gases (carbon and carbonic acid being in -excess); and Z is a cone the oxygen in which renders it less luminous -and free from combustible materials, its temperature being exceptionally -high, especially where the cone comes in contact with the point of the -cone Y. Because of its properties, Z is termed the oxidising or outer -flame, whilst Y is known as the inner or reducing flame, because when it -is applied to some easily reducible substance--say, lead oxide--the -oxygen in the substance heated mingles with the unburnt carbon in the -cone of the flame and produces carbonic oxide, the lead being thus -separated or reduced. The blowpipe flame is one of intense heat, even -that produced by blowing a common candle being capable of melting -metallic fragments when they are supported on a bed of charcoal. The -pointed flame gives the greatest heat, and this can be produced simply -by increasing or decreasing the space between the flame and the article -to be soldered or the metal to be melted. - -The particular advantage of a blowpipe is that it gives a fierce heat at -a very localised area, beyond which the solder does not run, and it -enables spots to be soldered, or parts to be unsoldered, adjusted and -re-soldered without allowing heat to stray and cause trouble at other -places. A useful little addition to the ordinary blowpipe is a small -washer soldered on near the mouth end (see Fig. 23), the object of this -being to raise this part off the bench and so keep it from contamination -with dirt, filings, etc., which are unpleasant to the lips. Sometimes -the washer is made elliptical and slightly concave to fit the lips, so -that it forms a convenient stop or steady when the blowpipe is held -between the teeth without help from either hand. - - -=Bunsen Burner, Spirit Lamps, etc.=--The bunsen burner is, of course, -the most convenient device for heating (when the bit is not in -question); but failing a gas supply, a spirit-lamp must be employed. -This is a small glass bottle with wick, methylated spirit being used. -Plumbers and gasfitters make use of metal tubular lamps fed with spirit -poured on cotton-wool, and having a blowpipe tube attached and coupled -up to the lips with a rubber tube; they also use wax tapers. - -[Illustration: Fig. 27.--Home-made Spirit-lamp] - -[Illustration: Fig. 28.--Another Home-made Spirit-lamp] - -A methylated wick lamp may be easily made out of a small “self-opening” -canister, as shown in Fig. 27. The holes near the top increase the -efficiency of the flame. Another spirit soldering-lamp is shown by Fig. -28. The container for the spirit can be made about 3 in. in diameter by -about 1-1/2 in. deep, with a handle soldered on. A glance at the -illustration will explain the burner. An outer wick surrounds a piece of -tube, which itself contains another wick. The spirit in the inner tube -is vaporised by the heat from the burner when the outside wick is lit. -The spirit vapour issues from a 1/32-in. hole at A. At B a ring is -slipped over the outer wick, holding it to the central tube. By lifting -the central tube the height of the vaporising flame can be adjusted. The -vaporising tube is a piece of 3/8-in. brass tube with a 3/8-in. gas cap -screwed on the end, or a brass disc can be brazed in. The total cost -should not exceed sixpence. - -[Illustration: Fig. 29.--Swivelling Gas-burner for Bench Soldering] - - -=Bench Blowpipes.=--The best form of gas bracket for bench use is one -having a horizontal swivelling arm, and screwed to the bench by a -flange, as shown in Fig. 29. The swivelling head is also a cock, which -shuts off the gas when the jet arm is pushed over at right angles to the -edge of the bench, as indicated, and the gas is connected by an iron or -compo pipe under the bench. A second gas tap should be arranged in the -supply to regulate the amount of gas, and for reasons of safety. A -simple device (see Fig. 30) may be made by anyone, and connected to a -rubber-pipe connecting head on the gas bracket supplying light to the -bench and workshop. - -A design of gas blowpipe which leaves one hand free is shown by Fig. 31. -This enables the worker to apply the solder to the work (holding the end -of a strip against it), after it has been brought to the melting heat of -the solder. The blowpipe is arranged so that it can be held in the hand -or dropped into a hole in the bench. - - -=Tapers.=--Tapers for a blowpipe flame are made by untwisting cotton -rope until the threads of the individual strands are straight. These are -then dipped in melted wax made by melting two wax candles over a gas -stove in a jam jar. They are repeatedly dipped until sufficient -thickness of wax is obtained. The wax should be just sufficiently hot to -keep melted. - -[Illustration: Fig. 30.--Simple Bench Burner] - -[Illustration: Fig. 31.--Gas Blowpipe for Bench] - - -=Catching-tray for Bunsen Burner.=--The blowpipe is not essential for -some kinds of work, such as when the job can be held wholly in the flame -without causing any damage. When solder is being melted to drop on to a -surface, the plain bunsen or atmospheric flame is also sufficient, -though in this case it is well to tilt the burner over so as to prevent -the solder dropping down the tube. An elbow fitted on the top of the -tube is handy in this connection, to deflect the flame at an angle, and -Figs. 32 and 33 show this, with the addition of a tray to catch the -dripping solder which otherwise would splash on the bench and cause -untidiness. The tray is riveted to a strip of brass bent round to slip -over the outside of the elbow, and a small pin riveted into the tube -prevents the tray from falling down. - -[Illustration: Fig. 34.--Section through Blowlamp for Soldering, -Brazing, etc.] - -[Illustration: Figs. 32 and 33.--Bunsen Burner and Solder-catching -Tray] - - -=Blow Lamps.=--A soldering lamp is used sometimes in the place of a -blowpipe, and it should combine perfect security with compactness and -portability. Tool merchants’ catalogues show a number of styles. In the -lamp shown by Fig. 34, benzoline is burnt. When the lamp is in use and -the body of it is very hot, the inside pressure does not exceed -three-fifths of an atmosphere, whether the regulator R is open or almost -closed. Thus the danger of explosion, which is such a drawback to some -of the lamps that use ordinary paraffin, is avoided. The upper parts of -the lamp are subjected to great heat and therefore are packed with -asbestos, which serves as a filter and stops any impurity in the -benzoline from getting to the burner. The flame can be lowered to a -glimmer when not actually in use, thus saving the trouble of relighting. -When the lamp is to be used, the regulator R is screwed up tight; and -care must be taken to ascertain, from time to time, that the burner or -nipple C is open and perfectly clean. If this becomes obstructed, it can -be cleaned by unscrewing the tube T and passing a fine steel wire -through the hole. The lamp should be completely filled with benzoline -every time it is to be used. A little methylated spirits is poured into -the basin A, and set alight. When the apparatus has become slightly -warm, the regulator is opened gradually. To extinguish the flame, the -regulator must be screwed up tight. If any escape is observed round the -screw of the regulator, the square P should be screwed up with the key -supplied by the makers, so as to tighten the asbestos packing. The lamp -above described is only one of a great number of such appliances, but it -is fairly typical of them all. The difference between a solderer’s and a -brazer’s blowlamp is merely one of size and power. - -[Illustration: Fig. 35.--Soldering Lading-can handle] - -[Illustration: Fig. 36.--Soldering Lug to Lamp Bottom] - - -=How to Operate a Mouth Blowpipe.=--The operation of using the mouth -blowpipe does not consist in blowing intermittent and strong blasts with -the lungs, as this would soon exhaust the wind power. For very light -jobs, however, this method is sometimes adopted; but once the proper way -is discovered, the user naturally falls into the use of this method. - -The proper way to keep a continuous blast is to breathe naturally -through the nose, and at the same time keep the cheeks distended by -forcing the air at sufficient pressure from the lungs. The cheeks -naturally resist the pressure, and force the air through the blowpipe. -The operation requires some practice and a clear nose passage. There is -practically no limit to the time a continuous blast can be kept up. - -The blowpipe flame is produced by holding the blast end of the blowpipe -just above the wick of the taper and touching the flame; the blast then -causes a long blue flame to project. This flame is hottest at the tip, -which is slightly brown. - - -=Typical Blowpipe Jobs.=--Some of the photographic reproductions in this -chapter show the methods of soldering comparatively light and heavy -articles. Fig. 35 shows a lading-can handle being resoldered. As it had -broken away, the old solder remained, and the joint did not need -cleaning. It is dabbed with the killed-spirit brush, and a small piece -of solder put near the joint. The flame is first played on the parts -away from the solder to get them to the requisite heat, and as the heat -reaches the solder it melts, and flows where required. Where the solder -should be the thickest, that part of the joint is inclined downwards. - -A job needing very much heat, and therefore a continuous blast for some -time, is shown by Fig. 36. A lug is shown being soldered to a heavy -brass lamp bottom. Before putting the lug in position the parts of the -joints have to be tinned. This consists of applying a film of solder. In -this case the heat is applied to the lamp bottom for several minutes, -and without loss of time the part where the lug fits is cleaned with a -fine file, the spirit brush dabbed on a piece of solder, put in -position, and the flame again applied. The solder almost immediately -flows over the cleaned portion; if it does not flow as required, the -flame is played on the solder and lamp bottom, a dab with the spirit -brush helping matters. The lug, which should have been previously -tinned, is placed in position on the lamp bottom, and with a slight -application of the flame, the solder flows and unites the parts firmly -together. It should be particularly noted that, when uniting light -articles to heavy ones, the light ones should be tinned first, and -secured to the heavier article whilst the latter is still hot. - -[Illustration: Fig. 37.--Soldering Wires of Vegetable Masher] - -[Illustration: Fig. 38.--Holder for Applying and Adjusting Solder] - -Fig. 37 shows the wires of a vegetable masher being soldered. There is -nothing special about the job, except that the solder cannot be placed -on the joint. To effect this a piece of tin (Fig. 38) is indented at one -end, and a small hole made in the centre of the depression. The bead of -solder is placed in this depression, and held over the joint to be -soldered; the flame is then played on the joint and on the solder which -flows through the hole. - -[Illustration: Fig. 39.--Brushing Solder around Dial Ring] - -[Illustration: Fig. 40.--Tinning Dial Ring] - -Figs. 39 and 40 show the method of tinning a brass dial ring. The ring -is filed clean and placed on a piece of asbestos board, the flame being -applied until the ring is sufficiently hot all round. A bead or two of -solder is placed on, and, as they melt, the solder is brushed round as -shown in Fig. 39 with the spirit brush, the flame being applied at -intervals to aid the flow. - -[Illustration: Fig. 41.--Re-soldering Kettle Spout] - - -=Re-soldering Kettle Spout.=--Refixing a spout in a “tinned” -wrought-iron or copper kettle. The spout and that part of the kettle -which comes in contact with it should first of all be filed bright and -clean. Next place the spout in position, apply killed spirits, and hold -it over a bunsen flame, as in Fig. 41, until sufficient of the strip -solder is melted to flow around and sweat through to make a strong sound -joint. Should any difficulty be experienced in getting the solder to -flow readily, apply a little more flux. - - -=Soldering Corroded Metal.=--When the surface of metal to be soldered is -badly corroded, and it is difficult to obtain a clean, bright surface -preparatory to soldering, it should be treated to a liberal application -of raw spirits of salts (hydrochloric acid), which will soon remove the -cause of the trouble, but all traces of the acid should be washed away -with clean water before attempting the soldering. It is also a good plan -in these cases to tin the surface by repeatedly rubbing it with a hot -bit and solder, together with plenty of killed spirits, before -proceeding with the actual soldering process. - - -=Soldering Small Work.=--When soldering two small awkward-shaped pieces -together, they can be held in position by pressing slightly into a piece -of damp clay. When the work has several soldered joints it can be buried -in sand or covered with clay to confine the heat to the part being -operated on. - -Although care should be taken to limit the solder to the area of the -joint, there are circumstances in many cases where it is difficult to -prevent some of it from straying. To clean this off, resort may be had -to the blowpipe, applying the blast and quickly wiping the surface while -the solder is in a molten state. Or it may be filed off while cold and -finished with a scraper or a knife and emery-cloth. Or if there is only -a thin film the knife or emery-cloth alone will suffice. - - -=Soldering Pipe Joints.=--Most joints in lead, tin and compo. pipe are -now preferably made by means of a blowlamp, or with a mouth blowpipe, -strip-solder being used. When making the joint, heat the pipe in the -immediate vicinity, and, dipping the solder in the flux, stroke it -around the pipe to form the joint. - -In soldering block tin or compo. pipe with a bit, if this is too hot it -will promptly melt the pipe. This is also liable to happen with very -thin zinc. The only way to prevent this is to have the bit just hot -enough to melt the solder, and not to let it rest any length of time on -the soft metal. - -[Illustration: Figs. 42 and 43.--Soldered Branch Joint on Tin or Compo. -Pipe] - -In making connections with soft pipe it is better to make use of brass -couplings, and these can be soldered more easily and safely by means of -the blowpipe than with a bit. First clean and tin both ends of the -coupling, and with the bit put a little ring of solder round about 1/8 -in. from the end, as shown at D in Fig. 42. Next with a penknife cut a -hole in the pipe B where the connection is wanted, a neat fit for the -end of the coupling tail A, scraping the surface of the pipe all round -the hole. Insert the coupling in the hole in a vertical position. -Sprinkle a little powdered resin round the joint, or smear it with -fluxite. Using the flame of a spirit lamp or a candle and a mouth -blowpipe, heat the upper part of the coupling, being careful not to -allow the flame to come too near the soft pipe. The solder will soon -melt, and run down into the joint (see D in Fig. 43), when the flame -must be instantly withdrawn. The same proceeding can be adopted in -soldering the other portion of the coupling into the connecting pipe. If -a vertical position is inconvenient for the coupling it can still be -soldered in that position, and afterwards twisted carefully into the -desired position. In Figs. 42 and 43, C represents a wood plug for -steadying the coupling tail. - -[Illustration: Fig. 44.--Soldering Birdcage Wires] - - -=Soldering Birdcage Wires.=--For this job, it is better to flatten out -the solder to the thinness of brown paper and with a pair of scissors or -shears to cut it into very narrow strips. Take little pieces about 1/4 -in. long, and with the fingers pinch them round the wires just above the -joints to be soldered. Touch each joint with a small quantity of killed -spirit, and apply the flame of a small blowlamp just underneath the -joint; this will cause the solder to run in the joint in an instant -(see Fig. 44). The flame is quite free from smoke, and does not -discolour the wire in the least, as the solder will run long before the -wire is red hot. Every joint may thus be neatly made. With a thin piece -of copper wire secured in a handle as illustrated, the solder may be -drawn any way desired to make special joints in awkward places, where -the point of an ordinary soldering bit could not be used. - - -=Sweating.=--In the preceding chapter it was shown how useful sweating -is, when accomplished with the help of the bit. In blowpipe work, also, -this method is of much utility, particularly in delicate work where -portions have to be joined up in very precise relations. After tinning -the joint faces the pieces are secured in accurate relationship with -binding wire, or by bolts or screws or other means, or a soldering clamp -is employed, having jaws which clamp the pieces and enable them to be -adjusted to the exact locations desired, and the flame then brought to -bear until the work is hot enough to cause the solder to run. - -An example of the usefulness of sweating occurs in the making or -repairing of metal name plates having superimposed brass, copper, or -other metallic letters. The plate having been flattened and polished and -the letters cut out, filed and finished, the backs of the letters must -be rendered chemically clean by careful scraping, and are next “tinned” -with soft solder. The tinning may be done in several ways, but the -easiest is by the blowpipe, using resin oil as flux. - -Each letter may be placed in succession on a lump of charcoal, using -plenty of the resin oil, and applying the flame of the blowpipe to the -surface while one hand holds the charcoal and the other the strip of -solder. To prepare the solder, which is sold in sheets by the pound, cut -some strips 1/3 in. wide. Take hold of one end 1 in. from the end, and -with a sharp knife scrape the surface, drawing the knife edge downwards. -Do not use the last 2 in. of the strip, as the handling of this part -makes it chemically unclean. The greater part of the solder should be -about the edges of the letters. The next operation is to solder the -letters to the brass plate. As the brass plate also must be chemically -clean, the parts where the letters are to go should be lightly scraped. -Having ruled parallel lines in order to get the letters in line, lay -each down in its proper place, and draw a pencil line round it; then -with a scraper just remove the surface of the brass where the letters -are to be soldered. A thin piece of solder is now placed underneath -each letter, and each in turn is fixed in its place and secured with a -loop of binding wire screwed up tight. Nothing now remains to be done -but to apply the blowpipe flame and resin oil, when the solder will run -underneath the letters. It is better to set the plate on some small -lumps of charcoal. When the letters appear to be set fast, remove the -plate and boil it in a solution of potash, about 1/2 lb. to 1-1/2 gal. -of water, and clean in dry sawdust. The resin oil may be made by -dissolving resin in sweet oil by gentle heat, until the oil will cause -the solder to run. - - - - -CHAPTER VI - -Soldering Aluminium - - -It is well known to those accustomed to the art of soldering that there -is no solder which operates with aluminium in the same way that ordinary -solders operate with tinplate, copper, brass, etc. Aluminium soldering -presents so many difficulties that it has been thought desirable to -devote a separate chapter to the subject. - -There is more than one reason for the difficulty encountered. Aluminium -does not alloy readily with solders at temperatures as low as other -metals require; and, secondly, aluminium alloys with lead solders only -with great difficulty, and with but a small proportion of lead at that. -Consequently, lead solders are not suitable for aluminium. Another and -even more serious reason is in respect to the refractory oxide which -forms at soldering temperatures, and which is undoubtedly responsible -for most of the trouble. - -The soldering of aluminium is one of the most debated subjects in metal -working. Almost as soon as aluminium was prepared on a large scale, it -was discovered that the ordinary solders and fluxes did not answer with -it. Either pure tin or pure zinc will wet aluminium, and can, therefore, -be used as solder for it; experience shows that the tin soon falls -apart, while zinc by itself is brittle and discolours badly. The -failure of tin is due to the fact that it forms with the aluminium an -alloy that is decomposed by the action of the oxygen present in the air. - -Although aluminium is popularly supposed to be non-oxidisable, really -the surface is covered with a very thin film of oxide, which prevents -solder from alloying with the metal. Aluminium when heated rapidly -oxidises. It is customary to scrape the metal before and during the -soldering; and although some workers say that it is useless to scrape -before soldering because oxidation immediately starts again, it is -obvious that a thin film is more easily penetrated than a thick one. -Often it answers to scrape with the copper bit during the soldering, -previously rubbing off the oxide with emery cloth. The work should, if -possible, be backed with asbestos, to keep up heat in the metal. To -discover whether the surface is thoroughly tinned, wipe off lightly, and -the untinned parts will then soon become apparent. If the oxide is not -scraped off beforehand, it will probably mix with the solder and form a -scum, which will make a neat flow difficult. Scum should be lightly -removed with an old knife blade. It is essential to “tin” every part to -be joined, as the solder will not take on any spot that has not been -rubbed in some way, unless previously coated. - - -=Solders for Aluminium.=--Hundreds of aluminium solders have been -invented, naturally all claimed to be strong and durable, the alloys -containing various metals, such as aluminium, antimony, bismuth, -cadmium, chromium, copper, lead, manganese, silver, phosphor tin, tin, -and zinc. A table of the most approved aluminium solders is here given. - -Many of the best solders for aluminium contain a small proportion of -phosphor tin. A molten alloy containing phosphorus placed on aluminium -tends to absorb oxygen from the impure film as well as the surrounding -air. - -COMPOSITIONS OF ALUMINIUM SOLDERS - - ----+------+-------+-------+----+----+------+----+------+----- - Tin | Zinc | Sil- | Alu- |Cop-|Bis-|Phos- |Cad-| Lead |Anti- - | | ver | min- |per |muth|phor |mium| |mony - | | | ium | | | Tin | | | - ----+------+-------+-------+----+----+------+----+------+----- - 72·5| 25 | -- | 1·5 | -- | -- | 1 | -- | -- | -- - 80 | 20 | -- | -- | -- | -- | -- | -- | -- | -- - 97 | -- | -- | -- | -- | 3 | -- | -- | -- | -- - 20 | -- | 10 | 70 | -- | -- | -- | -- | -- | -- - 90 | -- | -- | 10 | -- | -- | -- | -- | -- | -- - 65 | 27 | 5·75 | 2·25 | -- | -- | -- | -- | -- | -- - 30 | 20 | -- | -- | -- | -- | -- | 50 | -- | -- - 99 | -- | -- | -- | 1 | -- | -- | -- | -- | -- - 90 | -- | -- | -- | 9 | 1 | -- | -- | -- | -- - 6 | 77·5 | -- | 3·25 | -- | -- | -- | -- | 3·25 | -- - -- | 90 | -- | 6 | 4 | -- | -- | -- | -- | -- - -- | 80 | -- | 12 | 8 | -- | -- | -- | -- | -- - -- | 80 | -- | 20 | -- | -- | -- | -- | -- | -- - -- | 90 | -- | 5 | -- | -- | -- | -- | -- | 5 - 80 | 17 | -- | 2·25 | -- | -- | ·75 | -- | -- | -- - 75 | 22 | -- | 2·5 | -- | -- | ·5 | -- | -- | -- - 70 | 25 | -- | 3 | -- | -- | 2 | -- | -- | -- - ----+------+-------+-------+----+----+------+----+------+----- - -In making the solders here given, it is advisable to avoid loss of the -more easily volatile of the metals by adopting the following -precautions: The aluminium is melted first, the zinc is added in small -pieces, then tin in small pieces, and lastly the phosphor tin. - -Inasmuch as zinc alloys with aluminium more readily than does any of the -common metals, solders that will readily “tin” aluminium generally -contain zinc in varying proportions. The solders found most satisfactory -contain zinc, tin, aluminium, and a very small proportion of phosphor -tin; but they do not run very freely or fuse so readily as the ordinary -tin and lead solders, and it is necessary to use a higher temperature, -so high, in fact, that difficulty is found in using these solders with a -soldering bit, and it is generally necessary to use a blowlamp. - -While there is no solder that allows aluminium to be soldered with the -facility and success experienced with other metals, that of Richard’s is -extensively used, and seems to have given as good results as any. It -consists of the following ingredients: Tin 29 parts zinc 11 parts, -aluminium 1 part, and 5 per cent. phosphor tin 1 part--practically the -same as that given in the last line of the table. This solder has -withstood the test of time better than many of the patented solders, and -can be used in jointing aluminium to aluminium, also aluminium to copper -or brass, and without the use of a flux. In making the solder it is -advisable to avoid loss of the more easily volatile of the metals. The -aluminium should be melted first, then the zinc, tin, and phosphor tin -in the order named. - -When using phosphorus instead of phosphor tin in the making of aluminium -solder, it will first be necessary to incorporate it with the tin, for -which purpose take a length of 1-in. gas barrel, attach a screwed cap -at one end, and close the opposite end with a tin (not tin-plate) plug. -Remove the screwed cap, and, having carefully dried between blotting -paper the proper proportion of phosphorus, insert the latter in the tube -and replace the cap. Now put the plugged end of the tube into the molten -tin; this will melt the plug of tin and so allow the phosphorus to come -in contact with the molten metal. The ingot of phosphor tin formed is -afterwards alloyed with the other ingredients, as already explained. - - -=Fluxes for Aluminium.=--A large variety of fluxes have been tried with -more or less success, namely, borax, copper chloride, lithium chloride, -paraffin resin, sal-ammoniac, stearin, silver chloride, tin chloride, -venetian turpentine, tallow, vaseline, and zinc chloride. Stearin is -undoubtedly the most reliable of them all, but no flux is needed for -solders containing phosphorus, which is itself a flux. - - -=The Soldering Bit.=--The average temperature required to make a -satisfactory and thoroughly sweated joint in aluminium is from 650° F. -to 680° F., according to the size of the article. A blowpipe or blowlamp -will be of great value, and is frequently preferable to a bit. Should a -bit be used, see that it is of aluminium or nickel instead of copper, -the point and the soldered joint being kept much cleaner whilst removing -the film of oxide during the soldering operation. Another advantage is -that the point or “face” of the bit can be “tinned” with the same flux -as that which is used for the joint. More care must be taken in the -manipulation of the aluminium soldering bit owing to its lower melting -temperature than the copper and nickel bits. - - -=The Process of Soldering Aluminium.=--The soldering of aluminium must -be performed quickly to be satisfactory, as the metal, if not coated at -the first attempt, may be injuriously affected. “Tinning” the parts -required to be soldered first is another important factor; also the -distance of the overlap of the joints should not exceed more than 1/8 -in., so as to allow the solder to flow thoroughly through; it does not -flow so readily as when soldering other metals. - -In soldering large pieces, where the ordinary overlap is not allowable, -and where a butt joint would be weak, fit the pieces together as at A -(Fig. 45). - -[Illustration: Fig. 45.--Aluminium Fitted Together for Soldering] - -Solder always flows towards the hottest point. This tendency enables one -to direct its course under the blowpipe or blowlamp flame. A large flame -should only be employed in “heating” up the part to be soldered on large -and heavy work. With a small pointed flame directly on the solder and -the parts on which it rests, the solder will flow quickly, and leave a -smooth, even surface at completion. - -Some aluminium solders now on the market are so hard that it is -necessary to heat them and the work to redness before they melt. Sheet -aluminium is easily warped by heat, and also contracts badly. If the -solder is too high in melting point, the metal must also be brought to -that point to cause proper union. If a hole is being filled in, the body -of the metal on heating expands all round and partly closes the hole; -also both the solder and the patch whilst hot are slightly expanded. In -cooling, the hole enlarges, the patch contracts, and the solder also -contracts; cracks result. The body of the work, if not exactly evenly -made, will warp, which is fatal to engine and similar work. By using a -low-heat solder (melting point, about 700° F.) these troubles should be -avoided. - - -=Soldering Aluminium to Copper or Brass.=--Aluminium can be readily -soldered to copper or brass with fine solder (2 parts of tin and 1 part -of lead): tin the metals, using stearin as flux previous to making the -required joint. It is essential that both the “tinning” and soldering -should be thoroughly done. Do not expect the solder to pull the joint -together, but see that the joint is kept under slight pressure until the -solder is hard, otherwise the joint will not be perfect. Many workmen -refuse to place any reliance in such joints. - -Finally, it seems very likely that, at any rate as regards factory work, -the use of solder on aluminium objects will be wholly discarded in the -future in favour of fusion welding or autogenous soldering, in which -process no alloy is interposed between the surfaces to be joined. -Information on the subject is given towards the end of this book. - - - - -CHAPTER VII - -Wiping Joints on Lead Pipes - - -Plumbers make joints in lead pipes with soft solder which, by means of -cloths, they “wipe” to the shape shown by Fig. 47. - -Figs. 46 and 47 show the difference between a copper-bit or blowpipe -joint and a wiped joint. - - -=Plumbers’ Solder.=--As already stated, coarse, or plumbers’ wiping -solder, is made in the proportion of 2 of lead to 1 of block tin. Care -must be taken that the lead is quite pure and free from any other metal, -as zinc-adulterated solder will be difficult to use, and joints made -with it on service pipes will not be sound. In melting up scrap lead for -making solder, only sheet lead should be used, as the lead used in the -manufacture of sheets is much purer and contains a greater proportion of -pure pig lead. The scraps must be quite dry; a damp piece dropped into a -pot of molten metal may cause a serious accident, as the contents of the -pot may be blown out. - -To test the quality of solder when made, heat it as for wiping a joint; -the correct temperature is determined by dropping a small piece of -newspaper into the pot, and if it quickly burns and catches alight the -solder is right for using. Next pour a small quantity on to a cold but -dry stone or cement floor. This, on cooling, should have a few spots on -the surface about the size of a threepenny-piece, and on the under side -should be bright nearly all over. Solder of this quality would, if -properly used, stand any pressure without sweating. If the solder on the -stone or cement floor looks white on both sides, or has a few small -bright spots on the under side only, it is too coarse and requires more -tin. On no account should the solder be heated to redness, as the tin -rises to the top and quickly turns to dross (see p. 11). If this should -happen to solder that is being used for service pipes, it should be -rectified by adding more tin. - -[Illustration: Fig. 46 Fig. 47 - -Fig. 46.--Copper-bit Joint on Lead Pipe - -Fig. 47.--Wiped Joint on Lead Pipe] - -To purify a pot of “poisoned” solder (solder that contains zinc), melt, -stir in a handful of common sulphur or powdered brimstone until the mass -is of the constituency of wet sand, heat to the ordinary working -temperature, and carefully remove the crust that forms on the top, and -the solder will then be fit for use, except that a little tin must be -added to it. The presence of zinc in solder can be detected by the -difficulty of forming joints, the metal falling apart and working very -lumpy, and the joints when finished having a dirty grey appearance. - -When plumbers’ solder is bought ready for use from the manufacturers, it -is usually in the form of casts of eight bars, weighing about 56 lb. to -the cast. The best only should be used, as cheap solder is frequently -the cause of much trouble if used on high-pressure work, and joints made -with it are never of good appearance. To test manufacturers’ solder, -wipe a joint with it, and if it is of good quality it will work easily -at a good heat, and when cleaned off with tallow and a clean rag it -should be well covered with bright spots. - -Brass fittings should not be tinned by dipping into the solder pot, as -brass being an alloy of zinc and copper, the zinc may be melted into the -pot with disastrous results. - - -=Flux.=--The flux used is tallow, no other flux answering the purpose so -well, although mutton fat has been used as a substitute. Plumbers often -call tallow “touch,” and they frequently use it in the form of tallow -candles, the cotton wicks coming in handy for packing spindles of taps -and slides of gas pendants. - -An excellent plumbers’ black, soil or smudge, can be bought in packets, -and requires only to be mixed with water before using. Ordinary black -consists of lampblack, glue, and water. The black should be first mixed -with water, afterwards adding the glue, which must have been previously -melted in a glue-pot. Simmer this for a time to remove surplus water. -Test the black on a piece of sheet lead and dry off slowly. If it chips, -add more black, but if it rubs off add glue. - -The black should be made in small quantities, as it deteriorates if -kept. - -[Illustration: Fig. 48.--Joints prepared for Jointing] - -[Illustration: Fig. 49.--Marking-gauge for use on Pipe Ends] - -Another recipe is to place in the pot 1/4 lb. of size or diluted molten -glue and a little water; gently warm until the size dissolves, but do -not boil. Mix 1/2 cub. in. of chalk ground to a fine powder with a -pennyworth of lampblack, and then with a pallet knife incorporate some -of the melted size with the mixture on a flat board or stone to form a -thin paste, after which place the whole in the pot, warm, and stir -together thoroughly. Test as before. Old and thick soil is thinned with -porter or stout, but do not add too much or the soil will become so -sticky that the solder will cling to it. A little brown sugar, or a -little stout, added to the black will make it more tenacious, and cause -it to dry with a slightly glossy surface. Some plumbers soil their -joints after they are made, with black japan or thinned Brunswick black. -But it is doubtful whether the effect is so good as when a “dead” black, -such as given by ordinary soil, is used. - - -=The Cloths.=--Solder cloths for underhand joints should be from 1/2 in. -to 7/8 in. wider than the joint for which they are to be used, and about -1/2 in. longer than they are wide. Most plumbers use the same cloths for -underhand and upright, but it is preferable to use a special cloth for -4-in. upright joints with the length 1 in. less than the width. For -getting up the heat of an underhand joint on a small pipe a larger cloth -may be used until the worker is sufficiently skilled in joint wiping not -to burn his fingers when using the correct size. For 3-in. joints and -upwards a large cloth must be used first to get up the heat, the wiping -cloth being kept warmed and ready for use when the heat is right. This -large cloth, as used by some plumbers, is often long enough to lay on -the worker’s arm, but this is clumsy to use when the joint to be wiped -is in a cramped position, and is liable to let the pipe get burnt, as -the metal it holds cannot be readily distributed round the joint; 8 in. -by 9 in. is a good size to practise with on the bench, and as more skill -is obtained it can be reduced to 7 in. by 7 in. A diagonal strap should -be stitched to the back to take the little finger and thumb; the -position for this can be obtained by laying the cloth face downwards and -placing the hand on it with the finger slightly spread; the wrist should -be over the right-hand corner, so that when the cloth is being used the -edge is readily kept parallel with the sides of the pipe. Branch cloths -are made from 1-1/2 in. to 2-1/2 in. wide and about half as long again -in width. These cloths should be about seven thicknesses of material, -all others being nine or ten. - -White moleskin cloth is obtained from the tailor’s for making these -solder cloths, is usually 1 yd. wide, and costs about 3s. per square -yard. The usual method of making cloths is to cut a strip down the -selvedge of the material and fold up the strip till the desired size is -obtained; it can then be cut off the piece, and any odd ends left may be -used for packing a larger cloth. Another method is to cut a square piece -the required size, and then fold it three times each way. This makes a -rather clumsy cloth for small sizes, but makes a very good “blanket.” - - -=Horizontal or Underhand Joints.=--For making a successful wiped joint, -the ends to be joined must be a good fit and the temporary fixing must -be sufficiently strong so that the joints will not be broken in the -process of wiping. These two points should be always strictly attended -to. Service pipes should be tightly pressed home one in the other, the -cupped or female end shaved inside with a knife, but not close in as is -the case with soil or waste pipe; this allows the solder to fill up the -cavity, which effectually prevents any tendency to sweat. This principle -is followed up by some plumbers with branch joints on small size service -pipes, the male end being worked in with a twisting motion, to prevent -any solder getting into the pipes. All other pipe joints should be -closed, the female end being tightly worked in round the male end of -pipes as an extra precaution against the solder getting inside. It is a -good plan to black the inside of waste and soil pipes, so that the -solder will not adhere if any should get through when making the joint. -Fig. 50 shows the wiping of an underhand joint. - -Beginners often spend a lot of time practising “rolling” underhand -joints. This is bad practice, and will be of no use in wiping fixed -joints. Little advice can be offered with regard to the actual wiping, -constant practice being the essential thing. See that the solder is at -the correct heat. This is readily found by dropping a piece of newspaper -into the pot, and, if it quickly browns, the solder is ready for use. If -the solder is used too hot it will quickly burn holes in the pipe, and -if not hot enough a heat cannot be properly worked up, and the cloth may -get torn trying to move hard metal. For underhand joints pour on -steadily with a circular motion on to the sides of the joint, and on to -the soil at the ends of the joint, until sufficient solder in a molten -condition can be brought up to cover the top of the joint with the -cloth, which is held underneath it; then pour steadily all over the -solder until it runs back again. Repeat this continuously until the -solder can be worked in a substantial body all round the joint without -any hard solder being left at the underneath edges. Give the joint a -last pour on, and wash all the solder into the cloth. Bring the solder -smartly on to the top, and quickly work it all round the joint with the -wiping cloth, using two fingers of one hand for the top and back edges, -and the index fingers of both hands for the underneath part. The top of -the joint should be roughly shaped first and the surplus metal brought -over the back to the underneath; this should be worked into the bottom -of the joint with a slight sideways motion. The extra body of metal -should be used to warm up any hard edges, the surplus being brought up -again to the top and quickly thrown off to the back. - -[Illustration: Fig. 50.--Pipes Supported and Secured on Bench for Joint -Wiping] - -[Illustration: Fig. 51.--Finished Wiped Joint] - - -=Upright Joints.=--These are more trying to the worker’s patience but -are the easier to wipe. After the pipe has been fixed in position, a -lead collar should be fixed a few inches below the joint to catch the -surplus metal. A piece of stout string tied by a half hitch round the -pipe will prevent any leakage of the solder. In working up the heat of -an upright joint, care should be taken to work steadily round the joint -so that the heat is the same throughout. After sufficient metal has been -splashed on with the splash stick and ladle, and the metal is at a -moving heat, roughly shape up the joint with the splash stick, keeping -the metal fairly high on the joint; then splash on a little more hot -metal all round. A warm cloth is now used to shape up the joint by -bringing the lower metal up to the higher part, after which start to -wipe first with the hand as far round the back of the joint as possible -and bring the surplus metal to the front, the cloth being held by the -thumb and the index and little fingers; then change the cloth to the -left hand and repeat the operation. The joint should be finished off at -the back, although if quickly done the finish off should not be -apparent. The collar must now be taken off and the solder it contains -melted with a plumber’s iron. - -A plumber’s iron can be used to good purpose on these joints, especially -if they are out of doors and the weather is rough. The iron must be -heated to redness and well filed up. - -[Illustration: Fig 52.--Making Upright Wiped Joint] - -[Illustration: Fig. 53.--Wooden Collar or Platform to Catch Waste -Solder] - -[Illustration: Fig. 54.--Lead Collar to Catch Waste Solder] - -[Illustration: Fig. 55.--Pipes fully prepared for Jointing] - -Where possible, all joints to be wiped in their permanent position are -sprung away from the wall and temporarily fixed with steel points made -from 1/2-in. hexagon steel about 9 in. long and drawn out to a point at -one end. In some cases, more particularly soil-pipe work, the pipes -cannot be fixed away from the wall; a hole must then be cut into the -wall about 4 in. back and about 12 in. square to allow the joint to be -properly made at the back. - - -=Wiped Joint between Lead and Cast-iron Pipes.=--In wiping a lead pipe -to a cast-iron pipe perhaps the best practice is to file clean the end -of the cast-iron pipe first and then coat with pure tin, sal-ammoniac -being used as a flux. The pipe then is washed to remove the -sal-ammoniac, and afterwards “retinned,” using resin and grease as a -flux. A plumber’s joint then is wiped in the usual way. It is necessary -to take great pains to make a good sound strong joint between the two -metals, but even then in the course of time (it may be only a few years) -the iron will come out of the solder. The first sign of decay will be a -red ring of iron rust showing at the end of the joint. This rust will -swell a little and cause the end of the soldering to slightly curl -outwards. Eventually the rust will creep between the solder and the iron -and destroy the adhesion of the one to the other. The joint would -eventually become a loose ring on the iron pipe, but not on the lead -pipe, as the expansion of lead and solder do not differ to any great -extent. Only those metals that alloy together can be satisfactorily -joined by soft soldering, and the solder should contain as great a -proportion as possible of the metals to be united. - -The illustrations to this chapter (Figs. 46 to 55) are -self-explanatory. - - - - -CHAPTER VIII - -Hard-soldering with Silver Solder - - -Hard-soldering is chiefly of two kinds, brazing and silver-soldering, -the former being employed for iron and steel, the solder used being -known as “spelter,” a brass alloy which can be obtained in various -degrees of fineness. For copper, brass, and nickel silver, alloys -containing silver are the best solders. In both forms of hard-soldering, -the flux is borax. - -The methods of silver-soldering vary with the size of the work. A -jeweller may hold the work in his hand, on the end of a piece of binding -wire or on a square of charcoal, the heat being applied by a mouth -blowlamp from a horizontal gas jet, as already described. Larger work -demands a flame of greater intensity, and sufficient air can be supplied -only by a footblower or similar device, or, as an alternative, from the -flame of a suitable blowlamp. - - -=Silver Solder.=--This can be purchased at prices up to 3s. 6d. or so -per ounce in sheet form, about 1/32 in. thick. Where the solder is -melted down by the amateur, a good way to obtain the sheet form is to -turn the globule of molten metal on to the bench and to place a flat -iron on it; but the result will not be equal to a rolled ingot. - -An old shop method of making silver-solder is to melt up old silver -(using current silver coinage is an expensive method of obtaining the -silver, and is said to be illegal) with some _brass_ pins, not the iron -ones so common now. - -According to W. H. Jubb, two solders compulsory for silver articles that -have to be sent to assay for hallmarking are: (1) 12 parts standard -silver and 1 part brass; (2) 6 parts standard silver and 1 part brass. -No. 1 has a low melting point, and is termed “quick,” and No. 2, which -requires a higher temperature, is called “stark” (in some parts of the -country, “fine”), but the use of this term here is misleading. No. 2 -should be used at the first heating and No. 1 at the second. These -should make ideal solders for beginner’s use, as the chances of burning -the work, even thin brass, are almost nil. - -(3) 2 parts brass, 1 part standard silver; (4) 5 parts brass, 2 parts -standard silver. Whereas Nos. 1 and 2 are “silver solders,” Nos. 3 and 4 -are termed “German silver solders,” as they are not so white and are -used on German or nickel silver (an alloy of copper and nickel). Both -Nos. 3 and 4 are good, have a comparatively low melting point, are much -less expensive than Nos. 1 and 2, and, if plenty of wet borax is used, -will “strike up” well. No. 3 is recommended. - -“Standard silver” is about 95 per cent. pure silver. Old “sterling -silver” is 92·5 per cent. pure silver. - -In making any of the above solders the brass and silver should be melted -together, and care should be taken to see that the metal is clean -beforehand. Where large quantities of solder are made, the metals are -scoured with emery cloth before they are put into the crucible. - - -=Requisites for Silver-soldering.=--For light jobs in silver-soldering -the special tools and materials required are as follow: Suitable gas jet -or other flame, mouth blowpipe, scraper, jar containing a sulphuric acid -“pickle,” piece of slate, camel-hair brush, pieces of lump borax, two -grades of silver solder, charcoal block, iron binding wire. - -The pickle is made by pouring 1 part of common sulphuric acid into 20 -parts of water, and its function is to remove all dirt and borax from -the metal. Silver-soldered articles should not be thrown into the pickle -until they are nearly cold, as otherwise the joints may crack, but in -the preparatory annealing (that is, softening) of plain metal, wire, -rod or tubing, the article may be put into the pickle when hot--but take -care of the splashes! Plunging hot copper or brass into cold water does -not have the effect of hardening it. Before placing a job in the pickle, -remove any iron binding, as this is immediately attacked by the acid. - -Often it is advisable to heat the metal and put it “through the pickle” -before working on it, especially in the case of tubing that has been -lying by for some time and has become dirty. - -For heavier work, a foot-bellows and gas blowpipe, or else a blowlamp, -are essential. An “Ætna” paraffin blowlamp with horizontal burner will -be found quite satisfactory, although, of course, if a gas supply is -available in the workshop the user will find that a foot-bellows and -blowpipe are more convenient. A blowlamp or blowpipe requires a suitable -tray or “forge” of sheet-iron in which coke and odd pieces of brick or -tile may be laid and used to pack round the object whilst the flame is -being played on the part to be soldered. - -[Illustration: Figs. 56 and 57.--Clip for Holding and Applying Silver -Solder] - -[Illustration: Fig. 58.--Pricker and Spatula for Consolidating Joints -and Applying Solder] - -Among the smaller additional tools that will be required will be a clip -to hold the solder (Figs. 56 and 57) and a brass pricker (Fig. 58). - - -=Preparing the Borax Flux.=--Make up the flux on the slate by rubbing on -it a piece of the lump borax moistened with water. This paste may be -applied with the camel-hair brush to the parts to be jointed. The flux -prevents the oxidisation of the surfaces, which would resist the -amalgamation of the metals and the solder. - - -=The Method of Silver-soldering.=--In hard-soldering with silver solder, -first file or scrape the parts bright, and cover them and the solder -with the borax paste. Heat gently at first so as to harden the borax; -then continue to heat by blowpipe until a red heat is reached, at which -the solder will run. The secret is to blow continuously until the solder -runs, and not to stop half-way. - -For soldering a silver watch case, an ordinary easy-running silver -solder, which melts at a lower heat than silver, will do. But to make -sure, shred the solder into very thin strips, and apply plenty of borax -to them as well as to the joint to be united. Use the blowpipe gently at -first so as to bake the borax, then heat the case all over almost to the -melting point of the solder, and direct the flame to the part to be -soldered until the solder runs and glistens. Cease blowing instantly, -and plunge the case into a solution of sulphuric acid 1 part and water -10 parts, to whiten it; then wash in hot water and dry in sawdust. Be -careful to remove all steel springs before soldering the case. - - -=Soldering Small Work with Paillons.=--These are small squares, say, 1/8 -in., of sheet silver solder, made by using the snips as in Fig. 61, and -prepared by well covering with the borax paste. Each paillon is placed -in position with the tip of the brush, this job requiring a little -practice. The solder should be clean, and if not, should be made so by -passing through the fire and pickling. The work with the paillons in -position should be slowly heated by blowing the gas jet on a part of the -job farthest away from the solder; the borax will dry, and should the -solder have moved, replace it with a suitable tool or the point of the -wet camel-hair brush. The heat must not be applied too suddenly at -first, otherwise the borax will boil up and push off the pieces of -solder. The heat may be increased when the bubbling has ceased. Do not -hold the work too far away, or it will get dirty in the smoke of the -flame, or yet too near, else the gas will not be used to advantage. As -the work begins to get hot, slowly work the flame towards the joint -until the solder melts and runs into the joint. Give it now a little -extra heat to get the solder thoroughly down into the crevices, and then -let the work cool down. When nearly cold twist off the iron binding wire -and put the job into the pickle. Leave the work in the pickle about ten -minutes, when all the borax will be dissolved. - -[Illustration: Fig. 59.--Section through Pipes prepared for -Silver-soldering] - -[Illustration: Fig. 60.--Pipes prepared for Silver-soldering] - -[Illustration: Fig. 61.--Cutting Up Silver Solder into Paillons] - - -=Larger Work.=--An example of silver-soldering larger work is the -joining together of two pipes, one smaller than the other. The best -course to adopt is to file or scrape the end of the smaller and the -inside of the larger (reaming and filing them if necessary) until a good -fitting joint is obtained, as in Figs. 59 and 60. A strip of solder is -then cut off, and, after the joint is well coated with borax paste, this -solder may be wound round the smaller pipe. If the joint is soldered in -a vertical position, the larger pipe should be the lower. The heat -should be conserved by laying the work in the coke and building the -same round, or, if the work is too large or the joint in an awkward part -of the pipe, a shield of tin plate or iron should be placed behind the -joint so that the flame is thrown back on to the work. Should the pipe -be attached in close proximity to the joint to a heavy piece of metal, -then warm this metal up first, otherwise all the heat will travel to -this part, and the work will take much longer to get to the proper -temperature. In all cases where one part of the joint is of heavier -substance than the other, that part should receive the greater amount of -attention from the flame. - - -=Quenching Silver-soldered Work.=--Many craftsmen object to the cooling -of the work by plunging it into water or pickle whilst it is hot; but no -damage or cracking of the joint occurs, it is thought, if the work is -not plunged when it is red hot or anywhere near red hot. Plunging into a -pickle certainly cracks the burnt-in borax, which can be readily removed -and the joint examined to better advantage. Many a silver-soldered -joint has been passed as quite sound when it has only been the borax -that has been stopping the interstices, and only after it has been -placed under service for some time does the faulty joint make itself -apparent. - -Silver-soldering cannot be done on work that has been previously -soft-soldered unless the soft-soldered part is first cut away; but, of -course, soft-soldering can be readily accomplished after -silver-soldering or brazing so long as the work is clean and all burnt -borax is first removed. - - -=Removing Soldering Marks.=--Solder will run away from a part of a joint -instead of running into it when the edges of the joint have been -imperfectly cleaned preparatory to the application of flux and solder; -also, if some dirt has got into the flux, or on the paillons of solder -employed. Another cause is unequal heating of the joint, or allowing it -to expand too much whilst being heated. The resulting fire marks may be -removed by warming the articles on a pan over gas, and plunging them -whilst warm into the sulphuric acid pickle. Or the marks may be removed -in a hot and strong solution of potassium cyanide, and the polish -renewed by a light polishing with a revolving swansdown mop and rouge -composition. - - - - -CHAPTER IX - -Soldering Gold and Silver Jewellery - - -Two methods of soldering are in common use among jewellers and -silversmiths. Soft-soldering is done with fine solder (1 of lead and 2 -of tin), and is used for articles that will not bear much heating. The -metal is filed or scraped clean and bright where the solder is wanted to -run, killed spirit is applied, and a little solder is run on the -surfaces by applying gentle heat. Having thus been “tinned,” the parts -are placed together and heat applied until they unite, a spirit lamp or -a blowpipe being used. This is the sweating process, already referred to -a number of times. - -For soldering catches and joints to cheap metal brooches that have been -silver-plated or gilt, the same solder is used as in the above. Both -catches and joints can be cheaply purchased, hard-soldered on to small -plates, square, oval, or crescent shaped, to suit all kinds of brooches. -Take one of these and hold it with an old pair of soldering tweezers in -the flame of a spirit lamp, and give it a coating of solder on its under -side. First wet it with the killed spirit, and then place a small -portion of solder on it, and hold it in the flame until it flows all -over the plate. It can be assisted to flow evenly by a copper wire, -which is also useful to apply the acid flux. Having “tinned” the catch, -clean (by scraping bright) the brooch, and place the catch in position. -Direct a gentle blowpipe flame to it until it is seen to settle down and -the solder flows. Then wash it immediately in warm water to remove the -acid and dry in sawdust, kept in a warm place. Use as little solder as -possible, and only clean the brooch where the solder is required to run. -Attention to these points will ensure a neat job. - -Hard-soldering on jewellery, etc., is done with silver or gold solder, -and requires the articles to be heated to a bright red. The parts are -cleaned, and a paste of borax and water is applied as a flux. A small -piece of the solder is also dipped in the borax paste and laid over the -join. Gentle heat is first applied to bake the borax hard, then by the -use of a blowpipe the parts are raised to a red heat until the solder -runs. The instructions given in the preceding chapter apply generally. - -With regard to gold-cased jewellery, it is useless to attempt to -hard-solder gold that has the least trace of soft solder or lead on it; -the heat causes the lead to heat into and rot the gold, and the articles -will tumble to pieces. The only way to mend, say, a gold-cased lead ring -is by soft-soldering a tin band or plate over it, applying the heat very -gently to avoid melting the lead inside. - -For hard-soldering a gold ring without discolouring it, use solders -containing gold, the precious metal in the solder being afterwards laid -bare by a process of annealing and pickling. The solders are prepared -to suit the quality of the gold to be soldered, so that they may -“colour” well and thus hide the joint. The following is a list of -coloured solders: - -Best solder: Fine gold, 12-1/2 parts; fine silver, 4-1/2 parts; copper, -3 parts. - -Medium: Fine gold, 10 parts; fine silver, 6 parts; copper, 4 parts. - -Common: Fine gold, 8-1/2 parts; fine silver, 6-1/2 parts; copper, 5 -parts. - -The gold solder is cast in long ingots, rolled thin and flat, and cut up -or filed into dust, and thus applied to the cleaned joints, using borax -as a flux. After the joint has been closed under a blowpipe flame, the -whole ring is annealed on an annealing plate to a dull red heat, then -cooled, pickled in acid, and polished. The film of grease left by the -polishing process is washed off in hot soda water, and the ring dried in -hot sawdust. Hard-soldered rings may be coloured with a film of -electro-deposited gold. - -If the gold is of common quality, under 12-carat, to remove any excess -solder make a mixture by reducing to powder 1 oz. of green copperas and -1/2 oz. of saltpetre and boiling in 5 oz. of water. This will -crystallise when cool. Redissolve the crystals in eight times their bulk -of muriatic acid. For use, add boiling water, and place the gold in the -hot mixture. For gold of 12-carat or over, nitric acid and water (1 part -of acid to 2 of water) will dissolve the solder without injuring the -gold. - -Gold solders used on gold articles are made from gold of the quality of -the article--say, 18- or 15-carats--to which is added 1/12th or more of -silver and 1/24th or more of copper. The quality of the solder is always -a trifle inferior to the metal on which it is used, so that the solder -may melt at a lower heat than the article. The melting point of 18-carat -gold is 1995° F., of 15-carat 1992°, and 9-carat 1979°, while easy -silver solder melts at about 1802° F. This shows that although 9- or -15-carat gold could be used to solder 18-carat, it is not possible to -use 18-carat to solder 15-carat. The same principle applies to silver -and brass; and the quality of the solder has to be known before any -attempt should be made to carry out the actual soldering of an article. -Another important point is that thin gold articles, like brooches, will -not bear so hard a solder as the same quality of gold will do when made -up solid, as in the case of a bangle ring. Solder for 18-carat and -15-carat is made thus: Take 1 dwt. of the gold, and add 2 gr. fine -silver and 1 gr. fine copper; melt well together, and roll out thin. For -12-carat, the addition of 3 gr. fine silver and 1 of fine copper to the -dwt. is advisable; while for 9-carat the most useful solder is made from -1 part fine gold, 1 part fine copper, and 2 parts fine silver. - -Great care must be exercised in hard-soldering gem jewellery, as the -stones are likely to be injured. Diamonds are the only stones that it is -safe to heat to redness in soldering. Fancy coloured stones, such as -rubies, emeralds, sapphires, topazes, amethysts, garnets aquamarines, or -pastes must not be made hot. A ring with any of these stones may be -hard-soldered at the back if the stones are covered up with a pad of wet -tissue paper to keep them cool; but if the soldering has to be done -anywhere near the stones, they must all be taken out by un-setting. - -Articles set with pearls, turquoises, opals, or cat’s-eyes (these things -are not really “stones”) will bear no heat whatever, and must all be -taken out before soldering. - -In cases where it is very desirable to leave the stones in place, in -order to prevent their bursting when heat is applied to the jewellery, -cut a juicy potato into halves and make a hollow in both portions, in -which the part of the ring having jewels may fit exactly. Wrap the -jewelled portion in soft paper, place it in the hollow, and bind up the -closed potato with binding wire. Now solder with easy-flowing gold -solder, the potato being held in the hand. Another method is to fill a -small crucible with wet sand, bury the jewelled portion in the sand, and -solder in the usual way. - -To restore the colour of gold or silver after soldering, dip the -articles while hot into pickling acid (1 part of sulphuric acid to 10 -parts of water); or put them in a little acid in a pan and boil them in -it. Here, again, diamonds are the only stones that may be dipped hot, -and there is a slight risk even with them. Pearls, etc., must not touch -the acid, either hot or cold. - -After heating and pickling, all gold is of a pale colour, and the -commoner the gold the paler. However, 18-carat gold may be restored to -its original colour in a few moments by buffing with rottenstone and oil -on a leather buff or on a brush, and following with rouge in the same -way; or it may be burnished if the nature of the article permits this. -Poorer qualities of gold may be restored to their bright colour by the -same means, but this takes longer. Most 9-carat articles are gilt to -improve their colour, and after soldering must be re-gilt to restore -their original appearance. - - - - -CHAPTER X - -Brazing - - -Hard-soldering by brazing with spelter is used to a very great extent in -the metal industries, especially in the manufacture of cycles and -motor-cars. Although several mechanical joints have been tried in cycle -manufacture, the greatest number of joints are made by means of brazing -solder. A joint made in this manner is almost as strong as a weld, and -the steel tube itself will often break under a strain and the brazed -joint remain intact. Copper and brass tubes, when well brazed, will -stand a pressure of 40 lb. or more per square inch. - - -=Spelter.=--Hard brazing solder (spelter) is somewhat difficult to make. -The metals have to be melted in a crucible and cast at a proper heat, -and while in a certain condition have to be pounded or punned in a -mortar. This disintegrates the materials and forms crystals of various -sizes, some being as coarse as wheat grains, varying in fineness down to -that known as 0 0, which is very fine dust indeed, and used only on very -particular work, such as tubing 1/8 in. or 3/16 in. in diameter. The -quantity of 0 0 from 1 cwt. of solder is very small, the corresponding -quantity of coarse grains being much larger; so that unless a quantity -is required, it is cheaper to buy than to make. It is necessary to -employ the purest materials, and in purchasing hard solder it is -advisable to state the purposes for which it is to be used. - -As a general rule, a solder should melt at a heat just under the melting -point of the metals to be united. Now, in ironwork, or with the steel -used in cycle work, this is impossible, for the melting points of these -two metals are too high to be effected by the bunsen blowpipe or brazing -hearth; but to join two metals in which the melting point approximates -very closely to that of the solder requires great care in order that the -metals may not be fused and the join spoiled. The reason why the melting -point of solder should be about the same as that of the metals being -joined is apparent when it is remembered that heat and cold, vibration -and concussion, tension and compression, have very considerable effect -on metals, and that if the expansion and contraction of these under -working conditions is not nearly alike, disruption or opening of the -joint will follow. - -Hard solders or spelters are mainly composed of copper and zinc--that -is, they are brass alloy--the quality most extensively used consisting -of equal parts of copper and zinc. As the quantity of copper in the -solder is increased, so the fusing or melting point is raised. - -Ordinary copper melts at about 2,000° F. and zinc at about 840° F., and -a solder composed of equal parts of each metal has therefore a high -melting-point. - -A very hard solder consists of equal parts of silver and copper. -Generally, a spelter of different composition is required for iron, -copper, and brass work, that for the latter being required more readily -fusible than that for the former. A suitable spelter for ironwork is one -composed of 2 parts copper and 1 part zinc; a spelter for copper -consists of 3 parts copper and 2 parts zinc; while equal parts of copper -and zinc make a suitable spelter for ordinary brass work. If a very low -melting point be required, a little silver should be added to the -last-given spelter. - - -=The Flux.=--Borax is the best-known flux for brazing. It is beneficial, -however, to have the borax calcined (fused), as it settles down to its -work immediately when applied to the hot metal, whereas uncalcined borax -has a tendency to swell and fall off the work. - -Spelter is in the form of filings, a thin stick, or wire. Filings are -apt to be blown from the work. Brazing is a very useful, and, if -properly done, reliable, method of joining two pieces of iron. A brazed -joint is considerably stronger than a soft-soldered one, and easily -resists temperatures that would cause ordinary solder to run. - -The process is not at all difficult if there is sufficient heat, and, -for those who have no gas laid on, the purchase of a paraffin Ætna -brazing lamp can be recommended. With this lamp, of course, the bellows -is not used, and only an iron hearth with asbestos cubes is wanted; but -gas should be used if available. - - -=The Method.=--For satisfactory brazing, thoroughly clean the surfaces -to be joined, first with a file and then with emery-cloth, and, if -necessary, bind them together with thin iron wire. A flux of borax and -water mixed up into a thick paste is smeared round the joint, which -should then be warmed to get rid of the moisture. Heat the metal to a -white heat, dip the spelter into the borax paste, and apply to the part -to be joined, rubbing round the joint until the brass is seen to run, -when the heat can be cut off. The work should be almost covered in the -asbestos cubes, and the spelter applied all round and not only in one -place; failures to unite the parts mostly result from insufficient heat -or cleaning of the parts. - - -=Brazing-lamps.=--These lamps are constructed to burn benzoline or -paraffin, and the more powerful types are fitted with pumps so that air -pressure may be exerted on the oil. The paraffin or benzoline is thus -forced into the burner, and by passing through the previously heated -tubular coil is converted into gas, which issues forth out of the gas -nipple, mixes with air, and then burns with a blue atmospheric flame of -high temperature. After filling the lamp, a torch should be held under -the burner to vaporise the oil, and thus ignite the lamp, after which -pressure is applied by means of the pump. Do not start pumping too -soon--that is, before the burner is sufficiently hot to vaporise the -oil--or the oil itself will be forced through the gas nipple. The flame -may be regulated at will, to suit the work in hand, after the burner has -become thoroughly hot to set the lamp fairly going. When brazing, lay -the article to be brazed on some broken coke, charcoal, or firebrick, -and if the article is comparatively heavy, cover it over with some small -pieces (to conserve the heat) except where the brazing is required. -After applying flux and spelter to the previously cleaned metal, direct -the flame of the lamp on it, gently at first, until the spelter fuses -and makes the joint. - - -=Gas Blowpipe for Brazing.=--Brazing blowpipes should be fitted with a -combination air and gas regulator, by means of which both the size and -nature of the flame can be adjusted to suit the work in hand. When -choosing a blowpipe it is always better to make one rather larger than -the work in hand necessitates--the flame can be reduced when required; -by this means a margin of reserve is provided which is useful in -emergencies. A blowpipe whose dimensions are 10 in. long, having a -5/8-in. gas supply reduced to 7/16 in. at the nozzle, and a 3/8-in. air -supply reduced to 3/16 in. at the nozzle, will braze ordinary latch keys -and other similar work if used with a No. 3 size blower. As already -stated, a paraffin, petrol or benzoline blowlamp is a cheap and -effective apparatus, especially where the quantity of work to be done -does not warrant the outlay of a foot blower, gas blowpipe, etc., but -gas has advantages over the liquid fuel, inasmuch as the blowpipe is -more under control. The quantities of gas and air can be readily and -more delicately adjusted during the actual brazing process, then as soon -as the spelter fuses and the gas is turned off, the stream of cold air -soon counteracts any excessive heat. - - -=Making a Gas Brazing Hearth.=--The brazing hearth can be bought -ready-made, or can be cheaply put together by the worker himself, the -necessary materials consisting of two bellows, some lead piping, and an -old packing case to support a large size frying-pan--about 1 ft. 4 in. -by 1 ft. The bellows are fixed one above the other, interconnected by a -fixed lead pipe, one pair of bellows worked by the foot pumping air into -the pair above it, from which the air is taken to a bunsen blast burner -by flexible tube. This bunsen burner can also be easily and cheaply -made, and as this works very well and will be found useful for both -soldering and brazing, the following hints on making it are given. -First, get two ordinary large house bellows about 1 ft. square, or -larger if possible; the larger the better. Next a good strong packing -case about 2 ft. long by 1 ft. 3 in. high and 10 in. wide is required. -One end of the box will form the base, and to make it steadier two 1-in. -boards should be screwed across to protrude about 6 in. on each side, -the front one being considerably wider, as can be seen at T (Fig. 62), -which shows the apparatus with one of the case sides removed. The -packing case proper is denoted by the letter A; the part A S A was -formerly the bottom of the case, but is now the back; and the top A V A -was the end of the packing case. Half-way between the top and bottom a -shelf B should be fixed, having a large hole cut out of the middle at G -to accommodate the union piece (seen in section), which holds the lead -air-pipe communicating from the lower bellows to the upper. - -[Illustration: Fig. 62.--Home-made Brazing Hearth] - -In the back, near the bottom, at S, cut a hole for the nozzle of one of -the bellows, and above the shelf cut another hole at S^{1} to take the -nozzle of the other bellows. The bottom bellows C should have the top -handle extended by a piece of stout bent iron N to act as a pedal, and -should be screwed to the base. A central hole about 3 in. in diameter -should be cut at P to allow the air to reach the valve. Now get a piece -of lead pipe 1/2 in. inside diameter, and, having cut down the nozzle to -just under that diameter, force the mouth of the pipe over it as at S, -and bend the pipe F as shown, to reach the centre of the shelf B and -enter the hole G until flush with the top. Remove the lead pipe and get -a block of wood about 3 in. square. Cut off the corners and bore a hole -in the middle, so that the lead pipe will just pass through it, and -countersink the hole. Broach out the mouth of the lead pipe until it -becomes bell-shaped and fits the block of wood, so that its edge is -flush with the wood when pressed hard against it. This is clearly shown -at G, where the dark shading represents the wood block. Cut a leather -washer the size of the block, with a 1/2-in. central hole, and lay this -over the hole in the bottom of the top bellows where the leather flap -valve is. Bore two holes in the wood block, and screw this down tightly -to the bottom of the bellows, so that the bell-mouth of the lead pipe -faces the hole and has the leather between it and the block. This should -make an air-tight joint for the fixing of the pipe to the bellows. - -Next, push the nozzle of the bellows through the hole S^{1}, and screw -the bellows down tightly to the shelf B. Join the lead pipe to the -nozzle of the bottom bellows, and make an air-tight joint with glue and -tape bound round. Between the top of the upper bellows D and the top of -the packing case at V, a stout sofa spring E is fixed to keep the top -bellows shut down tight till air is pumped in from the bellows below. - -From a screw near the top of the case stretch a house-bell coil spring -M, and attach its lower end to the foot-plate or pedal N. This spring -tends to keep the lower bellows open. When pressure is put on the -foot-plate N, air is pumped from the lower to the upper bellows, and -thence along the flexible pipe R to the bunsen blast nozzle described in -detail later. If it were not for the upper bellows, the air would come -to the nozzle in puffs, but the spring E keeps the pressure constant, -and a steady blast is secured. The rubber pipe R should be of sufficient -length to reach the hand conveniently, and allow room for movement. - -The hearth K can be made from sheet-metal, with the edges bent upwards -to form a tray; or an old frying-pan will answer very well. Whichever is -employed, four iron stays or legs H must be used to raise it above the -top of the packing case as shown. These legs should be screwed at one -end to the sides of the case, and at the other to the pan, and if a -frying-pan is used, the handle may be cut and bent to form a hook as at -L; it then acts as a support for the blast nozzle. - -[Illustration: Fig. 63.--Blowpipe or Blast Gas Nozzle for Brazing -Hearth] - -For use with the brazing hearth, a blast gas nozzle on the bunsen -principle is required, and this is easily made from two pieces of -gas-piping, a right-angle joint, and two mouthpieces to take flexible -pipes. First, get 1 ft. of 3/4-in. brass (or iron) pipe and an elbow, -internally threaded at both ends. Cut 2 in. off the brass pipe, and cut -a thread at one end of the short piece and one end of the long piece, to -screw into the elbow as shown in Fig. 63. At the other end of the long -tube solder in a cock or mouthpiece to take a large diameter flexible -pipe from the gas bracket. Next get 1 ft. of 1/4-in. brass pipe, and -bend it to the shape shown at B, soldering a mouthpiece at F to take -the smaller diameter air-pipe R (Fig. 62) from the bellows. Bore a hole -through the elbow C, and push the pipe in, making a tight fit, and so -that it passes centrally through the larger brass tube until it nearly -reaches the end as shown at D. Run a shoulder of solder to hold the -small tube firmly in the larger one as at E, and unite with a drop of -solder the large tube A and the small tube B where they cross at G. - -The gas passes up the large pipe, and out at D, and a blast of air is -forced through the centre of the flame through the small pipe B. The -shape of the small pipe allows of it being readily hung up on the hook L -(Fig. 62) when not in use. Instead of the mouthpiece shown at H (Fig. -63), a cock will be found more convenient; but it should not be too -small, or it will restrict the flow of gas, which should be as great as -possible. No gas-cock should have less than 1/4-in hole. - -The “fuel” (heat conservers) consists of chunks or cubes of asbestos, -and when these are blown upon with the gas flame, the heat is quite -sufficient for moderately heavy brazing. Be careful not to get any kinks -in the flexible tubes, or the air and gas will be reduced in quantity, -if not stopped altogether. - -A square of thick asbestos (sheet) is useful for laying on small -articles whilst brazing, and a piece or two of charcoal will be handy -for silver-soldering. - - -=Brazing Iron and Steel.=--Before attempting to braze either iron or -steel the surfaces should be thoroughly cleaned by filing or grinding, -etc. Brass or copper may be cleaned by dipping in a solution of 1 part -nitric acid and 2 parts of sulphuric acid. This same solution can be -used to remove the scale after brazing. The parts should be fastened -together in the position they are to occupy when joined. The fastening -may be effected by the use of wires, screws, bolts, clamps, etc. If -practicable, the parts should be held in such a way that they can be -turned over during the brazing process without disturbing the relation -of the parts, thus affording a better chance to apply the flux and -brazing material. - -In brazing sheet metal, if the seams are not required to stand much -working after soldering, they may be joined edge to edge. When seams are -formed in this way, little nicks, about 1/2 in. apart, should be filed -out along the edges, so that the solder flowing through the nicks will -render the joint sound. If the seam is to be worked after soldering, a -small lap is necessary to ensure adequate strength. To form seams of -this type, first thin the edge of the metal along the ends that are to -form the seams, about 1/8 in. in from the edge, so that when the two -edges are lapped over each other the combined thickness at the seams -will be the same as the single thickness of the metal at other parts. -Cut a small cramp at the top and bottom of the seam, and fit the -opposite edge in these cramps. After preparing the seams by either of -the above methods, fasten binding wire round the articles so as to hold -the seams securely in position. Now powder some borax flux, mix equal -parts of the borax paste and grains of spelter, and along the seams -place sufficient of the mixture to solder them when melted. Some dry -borax should also be kept ready at hand, so that a little may be taken -and thrown on the solder at any point where the material does not appear -to be flowing freely. Gently heat the article by some suitable means, -such as foot bellows and blowpipe, so that it will expand equally, and -not disarrange the seam; increase the temperature until the metal is a -dull red, and the spelter runs. If necessary, with a piece of wire -flattened at one end gently rub the solder along the seam until every -part is joined. - - -=Brazing Copper Rod.=--For uniting two pieces of copper rod, 1/4 in. or -3/8 in. in diameter, first prepare the joint as at A in Fig. 64, and -file the surface of the copper clean in the immediate vicinity of the -joint. A mixture of borax and water and spelter should now be applied to -the joint, which should rest on a small heap of broken coke, the coke -being also built round it. The flame of the blow-lamp should be directed -at first on the coke surrounding the joint, and then gradually brought -to bear on the joint itself. If necessary, add a little more spelter -before any of it fuses, and when the copper begins to get red hot, -throw just a pinch of dry borax on the joint to facilitate matters. - -[Illustration: Fig. 64.--Dovetailed Joint in Copper Rod] - -[Illustration: Fig. 65.--Dovetailed Joint in Key Stem] - - -=Brazing Key Stems.=--In brazing together the broken parts of a key -stem, first it is necessary to file the fractured ends quite true; this -may entail the shortening of the key by 1/4 in. or 1/2 in., and as -another 1/4 in. will be lost in making the joint, it may be advisable to -use another key bow having a longer piece of stem than the one that was -broken off. With a warding file cut a dovetail on each of the ends to be -joined, as shown by Fig. 65. A small, half-round file will assist in -making the edges true and square. The pieces must interlock perfectly, -and when this is the case, very lightly hammer the joint, round which -then bind seven or eight turns of brass wire to act as spelter. Wet the -joint, sprinkle powdered borax on it (this is to serve as the flux), -and, holding the key in a pair of tongs, place it in a clear part of a -forge fire made with charcoal, small coke, or coal cinders, and -commence to blow steadily the forge bellows or blower. Failing a forge -fire, use a blowpipe, the key being placed on a piece of charcoal or -pumice-stone whilst the heat is being applied. If the forge fire is used -it is as well to support the key on a guard of thick iron plate having a -hole in its centre over which is the joint to be brazed. By this means -the necessary local heating is obtained, and much labour in cleaning the -key afterwards is avoided. On being heated, the borax swells and boils -up, and should be pressed down with a spatula, previously dipped in cold -water to prevent the hot borax adhering to it; a suitable spatula is -made by flattening one end of a 1-ft. length of a 1/4-in. round rod, -having at its other end an eye by which it may be hung when not in use. -With this spatula, also, powdered spelter may be added to the joint if -required. When the brass wire begins to run, assist the flow by adding -powdered borax, and when all the brass has run into the joint, rub off -superfluous molten metal from underneath and allow the joint to cool -gradually. When cold, file up and clean the stem of the key until only a -thin bright line of brass can be seen. - - -=Cycle Brazing.=--In cycle brazing, the first consideration is the means -of heating the heaviest joint to a brazing heat. This may be done in -several ways, by a paraffin blow-lamp costing at least 35s. to 40s., or, -what is better, a gas blowpipe 7/8 in. or 1 in. in diameter, with at -least 1/2 in. gas supply pipe and a fan or bellows to supply the -necessary air pressure. A small fan is far preferable to a bellows of -any description, the flame being steady and constant, and the operator -being able to devote his entire attention to the job. In the absence of -power, obtain a small circular double-blast bellows and hearth, costing -with blowpipe about £5. - -The brazing materials are brass spelter. No. 3 size, or brass brazing -wire and powdered borax; a tin to hold the mixture of spelter and borax, -and one for the plain borax; a piece of iron wire about 1/4 in. by 18 -in., flattened at one end to feed the spelter and borax to the joints; -and a brazier’s brush, which is desirable, but not absolutely necessary, -to brush the superfluous borax and brass from the outside of the joint -as soon as it is removed from the hearth; this saves much work in filing -up, and saves the files immensely. Do not purchase the borax ready -powdered, but buy lump borax, as that purchased ready powdered is likely -to be adulterated. In making the brazing mixture, use about equal parts, -in bulk, of No. 3 spelter and borax. - -In preparing the work for brazing, see that the surfaces are bright, -clean, and free from scale. The joints should be a good tight fit, free -from shake, and where a joint such as the back forks to the bridge lugs -is being made, see that the tube edges fit close up to the shoulder of -the lugs all round, and do not depend on the brass to fill up a badly -fitted joint. - -The chief things to observe are to make a sound joint the full depth of -the lug, and not merely to get a thin film of brass round the outer -edge. To do this, the flame should be directed on to the thickest part -of the lug first before getting the tube too hot, and feeding the joint -with borax before the metals get hot enough to scale. As soon as the lug -and tube begin to get a dull red, feed with borax only, then with brass -and borax, when it should flow almost like water and penetrate to the -deepest part of the joint. - -Another very important thing is not to “burn” the tube by getting it too -hot, which will spoil it and cause an early fracture. If the above -method of heating the lug first is observed, and the tube near the lug -kept “wet” with borax to prevent it scaling, this should not happen. - -Where the joint to be brazed lends itself to inside loading with the -spelter, the work should be so placed on the hearth that the brass -inside, when it melts, will tend to flow to the outside of the joint. -Then if borax only is used on the outside until brass appears round the -edges, it will be fairly certain that a sound joint will result. As soon -as this comes through, feed a little brass-and-borax mixture to the -joint, and, as soon as this melts, stop the flame and remove from the -hearth. If the flame is kept on too long after this, there is a -possibility of “soaking” all the brass out of the joint, especially so -if the joint is not a very good fit. - -Some braziers use a blacklead mixture for protecting thin tubes whilst -brazing; but care must be taken to keep it out of the actual joint, as -brass will not adhere to metal where this is present. - -Cycle frame joints can be brazed on an ordinary smith’s hearth, but it -is rather risky, and requires more skill than with a gas blowpipe. It -also requires a good clear fire and a light blast. The job should be -kept well fed with borax to prevent the tubes scaling and burning. The -joint should be loaded from the inside with about a thimbleful or less -of crushed borax and No. 3 spelter mixed in the proportion of about half -of each in bulk. The heaviest part of the lug should be heated first, -and the work must be turned frequently in the fire so as to avoid -burning the tube. If the joint is fed from the outside with borax until -the brass flows round it, a sound joint is ensured. This applies to a -joint where the lug is fitted inside the tube. Where the tube is fitted -inside the lug, a little brass and borax should be applied outside the -joint just as the inside charge has melted, which can be seen with some -joints by looking down the inside of the tube. When the tube is closed -both ends, such as the last joint of a frame, the job is more difficult -and requires careful judgment and skill to ensure a sound joint. - - -=Brazing Cast-iron.=--Although it has been dogmatically asserted both -that cast-iron can and cannot be brazed, it may be stated that the -general results of attempting this process are so indifferent as to -warrant the conclusion that this process cannot be recommended. In -brazing, one of the conditions essential to success is that the metal to -be brazed and the spelter should unite to form an alloy just where the -brazing occurs, and that this should take place spontaneously. This -actually happens when brazing copper, brass, wrought-iron, etc., but not -in the case of cast-iron. If, however, the reader desires to experiment -in this direction, the following hints may be useful. First of all, -remove all dirt and grease from the cast-iron, and then chemically clean -it by immersion in hydrochloric acid, afterwards well rinsing it in -clean cold water. A mixture of borax and water and spelter should now be -applied where the brazing is required, and gentle heat then brought to -bear on it until the water is evaporated. The heat should now be -increased until the casting is red hot in the neighbourhood of the -brazing; and some workers claim that at this juncture the best results -are obtained by dusting the red hot cast-iron liberally with boric or -boracic acid powder. A hard spelter should be used in preference to a -readily fusible one, otherwise the spelter would be fused much too soon, -and before the casting is raised to a sufficiently high temperature. - -An experienced worker who believes that it is possible to make a sound -joint in cast-iron by brazing, states that he has brazed articles with -equal parts of borax and boracic acid. The chief difficulty is the flux. -He has tried one called “Ferroment,” which seems to give good results. -The first casting brazed with it was 3 in. wide and 5/8 in. thick, and -this casting at the time of writing had been in work six months for -fifteen hours per day. This same worker prefers to roast borax before -use, as it stops on the work better. Also, when a deep, wide joint is -being dealt with, he finds it an advantage to smear on a little clay -underneath and the side, as should the joint get slightly hotter in one -part the spelter will run through and make an unsound joint. The heat -required to braze cast-iron varies somewhat with the spelter used. If -brazing by means of a smithy fire, the spelter will show a blue flame -when it starts to run, and the article must then be removed from the -fire. In using a blowpipe or blowlamp, the blue flame does not show, and -one has to look for the spelter melting, and see that it flows well -along the joint before removing the flame. Spelter which has been kept -in stock a good time may not flow well. The worker in question prefers -brazing wire to grain spelter, as by means of warming the end of the -wire and dipping in the flux (which will adhere to the hot wire), it may -be put just where desired. He collects all the soft brass turnings from -his lathe and uses them for brazing. - -Another worker has stated that those who have a forge of any kind will -find the following an effective method of repairing an iron casting. A -flux may be made of chlorate of potash 4 oz., boracic acid 1 lb., and -carbonate of iron 3 oz. These should be mixed well together and pounded. -The parts to be brazed together should be carefully cleaned by scraping -them, and brought to a bright-red heat. Then apply the flux and spelter -and increase the heat. - -Still another worker says that in brazing cast-iron, if powdered soda is -used instead of borax, the result will be a perfect joint. - - - - -CHAPTER XI - -Welding Iron and Steel under the Hammer - - -Iron and steel can be joined by heating until they become plastic and -then consolidating the two members of the joint by hammer blows, the -work being supported on an anvil. Correct heat and cleanliness are the -chief requisites. The “welding heat” corresponds with that temperature -at which the metal is in a state of partial fusion on the surface. The -better the quality of the iron, the higher the temperature it can stand -without being burned and ruined. Iron at a welding heat gives off -dazzling sparks, whereas ordinary cast steel is only an intense yellow, -but few sparks being evolved. Sufficient lap for the proper making of -the joint must always be allowed. When heated in a perfectly clear fire, -the metal may need no treatment prior to hammering; but otherwise it may -be necessary to sprinkle sand or some special flux over the work. At the -proper moment the iron is transferred to the anvil, and the union of the -two members of the joint immediately effected; delay means an imperfect -joint. In lifting the work out of the fire, remove it vertically and so -as not to collect particles of dirt on it. Keep a switch of brushwood at -hand for removing adhering matter. - - -=Welding of Steel Specially Considered.=--Some steels will “stand the -fire” better than others, which means that they will stand more heat -before they reach the point when they begin to burn. - -The different kinds of steel used in a general way may be summed up as -blister, spring, shear, double shear, and cast steel. Blister steel -will, as a rule, stand the most heating before beginning to burn, and -the others follow in the order given. The difference in heating will -vary from nearly a white heat on blister to the yellow heat of cast -steel. - -A simple method of ascertaining what heat a steel will stand before -beginning to burn is as follows: Heat the steel to its burning point, -and at various stages, beginning at the yellow stage, lay it on the -anvil and give it a few blows with the hand hammer. Repeat the process -until a heat is reached that will cause the steel, when struck with the -hammer, to give off sparks like small fireworks. When this stage is -reached it will show that the burning point is arrived at. - -Careful observations of these points will enable the smith to know just -when to begin to use the flux for welding, which, by the way, must be -just before the steel reaches the burning point. - -Another important point is the formation of the scarfs. These should not -be fullered down so thin or left in the same form as the scarfs as when -joining iron, and should be shorter (compare A and B, Fig. 66). - -[Illustration: Fig. 66.--Scarfs for Iron and Steel] - -In bringing the steel up to its welding point, care must be taken to -have it at a uniform heat throughout at the part for welding; and, to -get this, the blast should not be forced at the start, but used gently. -In some cases the blast should be stopped occasionally, to allow the -steel to soak. Then restart the blast, and gradually force it when -beginning to use the flux, continuing so until the welding point is -reached. Only light blows should be given at the start, just to cause -the two parts to stick together; but when stuck, the harder the blow the -better the weld. - -An idea seems prevalent that the flux has a certain influence on the -steel, and converts it into a form that makes it more weldable. The real -use of a flux in this case is simply to retard the heat, and form a coat -or shell on the steel, and so counteract and prevent the burning action -which takes place when heating steel in an ordinary blast fire. - -The reason why different fluxes are required for different brands of -steel is no doubt due to the differences in manufacture. As a rule, the -greater the heat the steel will stand before burning, the less it -requires a flux to protect it, so that in a great many cases a flux -consisting of some clean, sharp sand is all that is required; but the -steels that will burn at a lower heat require something more than sand -to protect them. Hence arises the necessity of adding burnt borax, -crushed glass, powdered marble, etc. - -The method of welding steel is as follows; but before proceeding to get -the heat make a point of having a shallow tin on the forge large enough -to hold a sufficient quantity of the flux, so that it will cover the -scarfed end when being dipped in same. Have a clean fire and plenty of -firing on the hearth, so that the heat can be well covered. Start with -gentle blast until the heat is nearly up to burning point. If necessary, -stop the blast and let the heat soak for a few seconds so as to ensure a -uniform heat. Gradually force the blast, and keep withdrawing the -“heats” and roll them well in the flux, and so continue until it is -thought that the heat is plastic enough to unite. Place the scarfs in -position, give a few light blows until the parts stick together, then -hammer well home and move smartly so as to ensure the proper joining -together whilst in a plastic state. When welded, do not continue the -hammering or tooling at too low a heat; but if further hammering is -necessary, re-heat the work. - -These hints are not applicable to every make of steel. With the special -steels manufacturers issue particular instructions. - -A flux for welding cast steel consists of 2 oz. each of powdered chalk, -soda and burnt borax, mixed with 1 lb. of silver sand. - -A firm of steel manufacturers recommend a mixture of 21 oz. of sand and -7 oz. of salt, moistened; the steel is to be treated in a fire of -sulphurless coal. - - - - -CHAPTER XII - -Making Blowpipes - - -=How to Make a Bench Gas Blowpipe.=--The blowpipe illustrated by Fig. 67 -gives a powerful flame. It can be clamped to the edge of the workbench -by means of a winged nut, a hole being made near the edge of the bench -to accommodate the bolt. A piece of hard wood A, 5 in. by 2 in. by 1 in. -thick, has a strong iron bolt B passed through at one end. A 2-in. cube -C, which should also be of good hard wood, is screwed firmly to the -other end of A, the combined block being perforated through the centre -to take a length of gas tube D, which carries a gas-bracket with flange, -elbow joint, and tap E. The flange should be screwed down to the top of -the block. The elbow joint allows the direction of the flame to be -adjusted within a wide range movement. The arm of the bracket is -removed, and a shorter tube F, 3 in. long, is substituted. This carries -a 1/2-in. iron [T]-piece G. The tube H, which is 3 in. long, should be -of brass, threaded at one end to fit into the [T]. - -[Illustration: Fig. 67.--Bench Gas Blowpipe] - -The air is conveyed through an 8-in. brass tube J 1/4 in. in diameter, -which should be smooth inside. This latter point is of some importance, -and, if preferred, a glass tube may be used instead of brass, the -current of cold air having a sufficient cooling effect to prevent undue -heating. The end should be cut off sharp with a file in the ordinary way -and left in that condition. Smoothing the edge by fusion in a flame will -not improve matters, but rather the reverse. Of course, the other end, -which comes outside, must be smoothed to prevent injury to the -indiarubber tube used for making connection with the bellows. The air -tube must be held firmly in the centre of the gas tube, while capable of -being moved in or out for the purpose of adjusting the flame. This can -be done quite satisfactorily by means of a short brass tube or nipple K, -threaded to screw into the [T] (_see_ Fig. 67). A sound cork should be -driven into this short tube so as to entirely fill it, a hole being made -with a cork-borer to admit the air tube. This hole must be exactly -central, and the cork must grip rather tightly. - -A foot-bellows is generally used for supplying the air, the bellows -being connected with the air jet J by means of an indiarubber tube. The -tube D, which should extend an inch or so below the bench, is to be -connected with the gas supply. - - -=A Simple Gas Blowpipe.=--A simple form of gas blowpipe is shown in Fig. -68, the rubber tube connecting it with the gas supply being fixed on the -pipe at the point of connection with the cock. To construct the -appliance, one end of a piece of brass gas pipe of the required length -with, say, a 3/8-in. bore, is bent as shown, whilst at the back of the -curve thus made a hole is drilled to admit a tube A 5/16 in. in -diameter. This should have one end (_see_ dotted lines) bent to -correspond with the angle previously formed in the larger tube, whilst -its other extremity should be bent upwards. Make these pipes red hot -where they are to be bent, and, if they are afterwards plunged in cold -water, the material will to some extent be softened, and its tendency to -split will be obviated. The smaller tube is passed through the hole in -the bend of the larger one, the ends being almost flush and quite -concentric. Solder the parallel portions of the tubes together, and then -fix a gas-regulating cock to the larger one, as in Fig. 68. The end is -then connected to an ordinary bracket or burner by means of an -indiarubber tube G, and a short piece of tubing is fitted with a bone or -other mouthpiece, and attached to the projecting end of the air tube. -This instrument will do any soldering, and will be suitable for melting -gold, silver, and brass, or brazing odd jobs in iron or steel. Of -course, when used for the last-named purpose it would be in conjunction -with asbestos tubes or other supports. - -[Illustration: Fig. 68.--Simple Form of Gas Blowpipe] - -[Illustration: Fig. 69.--Larger and more efficient Blowpipe] - - -=Proportion of Air to Gas.=--As regards the relative volumes of gas and -air for blowpipes, the late Mr. Thomas Fletcher said that, speaking -roughly, but still sufficiently near to make a correct rule by which to -work, a blowpipe requires one volume of gas to eight of air. If the gas -is supplied at a pressure equal to 1 in. of water, and the air at eight -times that pressure, then, to get the best effect, the area of the gas -and air pipes should be equal. If the air supply is equal to 16 in. of -water pressure, the gas pipe must be double the area of the air, and so -on in proportion. Some makers assert that a better working flame is -produced by using ten volumes of air to one volume of gas; but, of -course, if the blowpipe is fitted with taps, the supplies can be -adjusted easily. It will be found, however, that any practical departure -from Fletcher’s rule will result in a loss of power. - - -=Capacities of Blowpipes.=--It has been said, a blowpipe with a 1/8-in. -air jet, if worked with an air pressure of 10 oz. per square inch--that -is, 15 in. of water--will braze up to about 1/2 lb. total weight; or in -other words, will securely unite two pieces of brass each weighing 1/4 -lb. With the same pressure a 1/4-in. bore air-jet will braze a total -weight of about 2 lb., and so on in proportion. It will be understood -that the air jet is measured at the point at which the blast leaves the -air tube, whilst the area of the gas supply is that of the annular space -between the two tubes. When the air tube is thus carried inside the gas -tube (_see_ Fig. 69), the tool appears to be much larger than it really -is, and this accounts for the fact that a 1/2-in. size blowpipe with the -air tube fixed outside the gas supply is just as effective as one of the -3/4-in. size which carry the air tube inside the stem. All indiarubber -tubing must be perfectly smooth inside, for if it is wired or in any way -rough, the resultant friction will cause a loss of pressure. It should -also be of as large a bore as is convenient. - - -=Large and Efficient Blowpipe.=--A large and efficient blowpipe that can -be made in a few minutes is shown by Fig. 69, the only materials -required being a [T]-coupling and diminishing socket, an elbow, and one -or two pieces of pipe. The air tube A (represented for the most part by -dotted lines) passes through the diminishing socket until it almost -reaches the nozzle of the blowpipe, with which it is concentric. By -using the elbow D, the two supply pipes are brought parallel to each -other, so that the indiarubber connecting tubes can be more easily held -in the hand like reins, as by simply squeezing them the flame can be -readily regulated. Sometimes, in cases of emergency, a plug drilled to -meet the air tube is used in place of the socket. The plug is thrust -into the end of the [T]-socket; but in all cases it must be airtight. -This blowpipe can be used efficiently only in conjunction with a foot -blower. - - - - -CHAPTER XIII - -Managing Blow-lamps - - -The stoves and lamps burning paraffin in the form of vapour have become -very popular on account of their good heating properties, portability, -and little attention required. They consist of a container holding -paraffin, a burner with a heating tube attached is screwed to the -container, and a tube leading almost to the bottom. A small air-tube, -similar to a cycle-pump, is fixed in container, the handle and cap only -being in sight. When the burner tubes are heated, a thumbscrew on the -filler caps is closed, and a few strokes of the pump puts a slight -pressure on the oil in the container. The oil is forced up the central -tube to the burner; but before reaching this it has to flow round the -heating coils, and in so doing is turned to vapour. The outlet at the -nipple being very small, causes the vapour to issue with some force, and -it mixes with the air, forming a mixture which burns with a non-luminous -flame similar to that of a bunsen burner. This flame plays on the -heating coils, and once started, the lamp is practically automatic; a -stroke or two from the pump will keep it going until the oil is -consumed. - -There are patterns that use petrol or benzol, their action being -slightly different. Petrol and benzol are light spirits, which give off -inflammable vapour at a much lower heat than paraffin does. Advantage -is taken of this fact by causing burner and nipple to be in one solid -brass casting, so that when the nozzle is heated, the brass conducts the -heat back to the nipple and so vaporises the petrol, which is fed to the -nipple by a thick wick contained in a tube which reaches almost to the -bottom of the container, the wick touching the bottom. - -To start either paraffin or petrol lamps, the exit tube or nozzle is -heated. The petrol lamp has no coils round the nozzle; but comes -straight from the holder to the exit nipple. The size of flame is -regulated by a needle valve fitted with a wood or fibre handle. The -petrol lamp has no pump, except on high-power brazing lamps whose use -requires expert handling. - -The chief trouble with lamps using paraffin is that the burner becomes -choked; this is shown by the lamp jumping out or the flame not attaining -sufficient heat. The makers supply a proper cleaning needle, a sheet -stamped to form a handle and a piece of fine steel wire fixed at one -end. Nothing else, such as pins, etc., should be used, or the hole in -the nipple becomes enlarged, and emitting too much gas, causes a smoky -flame. The cleaner should be used each time before lighting. A good way -to avoid this trouble is to use a small funnel with fine brass gauze -soldered in the body when filling. White Rose is a quite satisfactory -oil for these lamps. - -After considerable use the heating coil becomes choked with carbon -deposit. A new heater tube can be obtained, or the old one cleaned by -drilling two or three holes in the ends and passing a piece of flexible -wire (such as Bowden brake wire) through the heater and removing the -obstruction. After getting it clean, tap out the holes and fix suitable -screws, flat under the head, with a piece of asbestos to make a tight -joint. - -If a larger flame is not obtained by pumping, take the cap off the pump -and draw out the plunger; the leather is probably worn. Fit a new one; -or it may have become hard, in which case apply a little oil and open -out carefully. The retaining valve is in the centre of the pump bottom, -and is removed by using a long key down the pump barrel. The valve is in -four pieces. See that the spring is free and that the cork is in good -condition. When replacing, take care not to get it cross thread, and -screw firmly home. The washer under the filler cap is of rubber and cuts -through in time. Do not use pliers to screw down; it will go gas-tight -with the fingers if the washer is good. - -To remove the nipple from which the gas issues is almost impossible -without a proper key. This has a universal joint, which allows it to be -rotated, although the handle is almost at right angles with the burner. -Keys and all other parts mentioned can be obtained from any dealer in -these lamps. - -With the lamps using petrol, the only parts requiring attention are the -plate from which gas issues and the wick. Unlike the paraffin nipple, -this is a circular stamping of brass approximately 3/4 in. in diameter -with a fine hole in the centre. To remove this disc, pass a long flat -screwdriver blade through two openings in the nozzle and turn to the -left (anti-clockwise), holding the body of the lamp firmly on the bench. -Before fitting a new disc, thoroughly clean recess and remove any -deposit from the inside of the valve box. Unscrew the needle and gland -if there is any leak there, and clean and repack with asbestos yarn. A -little glycerine on the packing appears to be an advantage. Place the -disc in position, dip an asbestos washer in water, and screw the nozzle -firmly down. - -The wick inside the lamp filters the spirit before reaching the nipple -and occasionally needs replacing. Remove the cap from the bottom of the -lamp, and with a piece of thick wire flattened at one end and filed to a -hook, push it up the tube and withdraw the old wick. The new one is -simply put in its place and the cap screwed tight. The washer under the -filled cap is of cork and rarely gives any trouble. - - - - -CHAPTER XIV - -Making Blow-lamps - - -=A Paraffin Brazing Blow-lamp.=--The brazing blowlamp shown in Fig. 70 -was made at a total cost of less than 4s. The illustration is printed to -a scale of about one-quarter full size. The lamp illustrated is not a -mere experiment, as the writer of this description had a similar one in -use for over two years, and during that time brazed hundreds of jobs -with its aid. - -The container is of tinplate, and adapted from a workman’s tea can. When -purchased this will have a wire handle and two hinges, and these should -be removed and soldered up. The handle shown at H is made from a strip -of iron, 1/8-in. by 5/8-in. section, bent round to the shape shown and -riveted to the side of the container. These rivets should be well -soldered over inside to prevent leakage. The joint of the longer strip -is shown at X. The lid should next be taken in hand, a 5/16-in. hole -being drilled at one side close to the handle, to take an ordinary Lucas -cycle valve. A leather washer is fitted inside, and also one outside -under the lock nut, the latter being then tightly clamped up. - -At E is shown the filling cap, the body part of which was taken from an -old paraffin oil-lamp container, and the screw cap made at the local -brass works; but this fitting can be obtained in a finished state from -many model-fittings manufacturers. This is soldered to the lid in the -position shown, a hole being afterwards drilled in the tin to suit it. - -[Illustration: Fig. 70.--Paraffin Brazing Blow-lamp, the container being -shown in section] - -The cock shown at D is an ordinary gas-cock, with a length of 3/8-in. -outside-diameter copper piping screwed and sweated in beneath. This is -passed through a hole drilled in the lid for its reception, and the base -of the cock is then sweated in position. Note that the length of this -pipe is such that when the lid is in place it clears the container -bottom by 1/8 in. - -The coil of piping at P is 3/8 in. diameter copper tube coiled round to -the shape shown, the lower end being tightly screwed into the top of the -cock. The opposite end is screwed for a short length of 3/8-in. gas -thread, and very tightly fitted with a screw plug such as that used by -plumbers for shutting off a portion of gas piping. Before screwing this -on, a small hole about 1/32 in. in diameter should be drilled in the -middle of same; this is the nipple for the exit of gas to the burner. - -The 3/8-in. copper tubing should not require filling with anything -before bending; this operation is best done round a mandrel of wood. No -heating is necessary. A certain amount of flattening of the tube will no -doubt occur, but this is immaterial. The end of the flame tube is, of -course, open, otherwise the flame could not emerge. The nipple end of -the flame tube is also quite open, with the nipple end of the coil just -projecting inside. The portion of tubing shown dotted in Fig. 70 takes -the vapour from the coils to the nipple; it does not pass through the -coils, but at the back of them, and bends round as shown. - -The lid of the container should now be carefully soldered down all -round, and then the 3/16-in. brass stay rod shown at S must be fitted -and both ends sweated over. It is essential that this stay is not -omitted, as otherwise the pressure to which the container is subjected -would bulge out the ends. - -The flame tube A should now be made of 1/32-in. sheet-iron, being held -in place by two or three clips riveted on and bent over the coil ends as -shown at C, only one of which is shown for clearness. The flame tube -does not taper, nor is the back end closed up. Its diameter should be -1-1/4 in. and length 3-1/2 in., but this depends on the size of the hole -in the nipple. No holes are required in this tube, as all the air is -drawn in at the end. The nipple has a gas thread cut inside it, and it -is screwed tightly on to the end of the copper coil. The length of the -pipe from tap to coil is not important; about 9 in. will be -satisfactory. - -The best means of joining the nipple to the tube is to screw the end of -the tube before bending it round at the end, and then to screw the -nipple on tightly. The pipe can afterwards be bent as shown. - -The jet hole in the nipple should be about 1/32 in. bare, and should be -so drilled that the issuing gas passes through the centre of the flame -tubes. The tube is open at both ends, to allow air to be drawn down and -complete the combustion of the paraffin vapour, the mixture igniting and -burning properly when the vapour passes out at the other end and comes -into contact with the atmosphere. - -To use the lamp, it should be filled about two-thirds or one-half full -of paraffin oil, and the container cap then screwed hard down with a -leather cap as a washer. A cycle pump should then be connected to the -valve V, and a few strokes given, the cock D being meanwhile closed. The -copper coil should next be put into a gas flame or the fire for a few -minutes until nearly red hot, and then the cock D should be opened a -shade, which will allow the paraffin to rise up the pipe I and enter -the coils P, where it will become vaporised, and the gas will then issue -from the nozzle N, and burn at the mouth of the coils. - -The lamp may then be applied to the job, and five or six more strokes -given to the pump, when the flame should burn with an intense heat and -give out a roaring noise. - -The theory of action of lamps of this character is as follows: The -pressure of air in the container forces the paraffin up the copper tube -into the coil, where it is vaporised by the red-hot piping. The vapour -then issues at some pressure from the nipple hole and, passing down the -flame tube, an ejector action is caused which draws air in with it. This -air mingles with the paraffin vapour, and when the mixture issues at the -other end, and comes into contact with more air, combustion takes place. - -The heat produced by the lamp should be quite sufficient to braze the -bottom bracket of a motor-cycle frame and other similar jobs. The size -of nipple with relation to the size of the flame tube is most important. -If the flame tube be too large in proportion, the result is an excess of -air, which cools the gas unduly and the flame dies out. A candle is put -out in a draught from the same cause. On the other hand, if the flame -tube is too small, or the nipple hole too large, the result is an excess -of gas, causing incomplete combustion and a partly luminous and smoky -flame, with less heating power. To ascertain if the nipple hole is too -small, take a strip of tin and, whilst the lamp is burning, hold the -tin partly over the end of the flame tube, so as to restrict the amount -of air entering, and note the result. - -If the drawing (Fig. 70) be regarded as 4 in. to 1 ft., and the lamp -made accordingly, it will be of ample size to braze small and model -boilers. It must be understood, though, that the size of the lamp alone -does not govern the size of the flame, this depending entirely on, -firstly, the size of the nipple, and secondly, the pressure of air in -the container forcing the vapour out. The larger the container, the -longer the lamp will burn without refilling, and, incidentally, the -larger it is the weaker the container will be, and vice versa. - -Should this lamp be required for brazing and silver-soldering articles -about 1/2 in. in diameter, it must be altered, as it is obviously much -too large. The same container will do, of course, although perhaps -rather unwieldy. If preferred, another container just half the size -could be made; this will be handier in use, although it will not allow -the lamp to burn for so long a period without recharging as the larger -pattern. For the tubing, 3/16-in. copper tube, preferably solid drawn, -will be suitable. This should be heated to a dull red and then quenched -in water to anneal it, this making the task of bending it much simpler. -If it kinks too much in the bent portions, pour some molten resin into -the tube, one end being plugged up for this purpose, and when set, bend -to the shape desired. The resin can be heated and run out afterwards. -The flame tube may be half the diameter and length of the one -illustrated, but no hard and fast rule can be given for the dimensions -of this part of the lamp, as the size of the nipple hole has everything -to do with this. Make the latter just big enough to admit a fine needle. -A simple method is to drill the cap almost through, and then punch the -rest through with the point of a needle. By experimenting, it will be -easy to find the right proportions of flame tube and nipple hole. The -screwed joints should be a metal-to-metal fit as it is termed, that is, -they should fit so tightly when screwed home that no leakage is -possible. This can be ensured by seeing that all male threads are a -tight fit in their respective holes. - - - - -CHAPTER XV - -Electric and Thermit Welding Briefly Considered - - -=Contact Welding.=--The electric welding of iron strips and sheets is -usually done by the Thomson process of “contact-welding.” In this -process the metal is brought to a welding heat by passing a very large -current through the joint to be welded, which, by virtue of its high -resistance in relation to other parts of the circuit, develops great -local heat. When the correct temperature for welding is reached, the -joint is pressed together by mechanical means, and the current -interrupted. In Fig. 71 the necessary arrangements for the welding of a -steel rim are sketched. A is the iron core of an alternating current -transformer and B the primary winding supplied with alternating current -either from a works dynamo or a public supply, and controlled by a -double-pole switch C. The transformer has a secondary winding consisting -of a single copper strip of very heavy section D, in which secondary -currents of low voltage but very large volume are induced. This winding -D terminates in two heavy metal clamps E, one fixed and the other -capable of movement by rack and pinion or screw, and the clamps must be -shaped to the contours of the work F they are intended to hold, so as to -fit well and present as little electrical resistance there as possible. -The butt ends of the wheel rim are brought into contact, current -switched on at the transformer primary, and immediately a very heavy -secondary current passes round the “winding” D, generating intense heat -at the junction of the metal rim G held in the clamps, where the -electrical resistance is comparatively high. In a few moments the joint -will arrive at welding heat and the screw feed is then operated, driving -the joint together and completing the weld, except so far as a little -hand dressing may be found necessary. Directly the weld is established -the current is switched off at the mains and the job allowed to cool -out. Nothing less than 5 kilowatts to 10 kilowatts is likely to be very -satisfactory for hoops about 3/4 in. by No. 16 gauge, and the current -must be alternating. The primary voltage and frequency is immaterial, as -the transformer can be wound to suit the circuit conditions whatever -they may be. - -[Illustration: Fig. 71.--Electric Contact Welding of Steel Rim] - -The method of welding by resistance, that is, by raising locally the -welding point to the temperature required by bringing the two surfaces -into contact until their high resistance produces a welding heat and -then squeezing them together, is by far the most manageable and -satisfactory commercial process of the two electrical processes. It is -adapted for “spot-welding” or producing local adhesions between metal -plates after the manner of riveting, for butt or end-on welds, for -seams, chains, rings, etc., and automatic welding machines are now made -that can deal with no less than 1,500 welds and upwards per hour with -semi-skilled labour, with the least possible percentage of failures and -a very low cost for electrical energy. Alternating current is essential -with this type of weld, and is used to energise a step-down transformer -of special construction. - - -=Arc Welding.=--Notwithstanding the superiority of the resistance -welding process to most commercial work, particularly that of a small -kind necessitating rapid repeat work, the “arc” method, which has been -in use for many years, and was probably the first experimented with, has -now become largely used on work where it was thought impossible to adapt -it a few years ago. The system is extensively employed in iron and steel -works, shipyards, and boiler works, and the class of work it is employed -on varies from the dismantling of iron and steel buildings, by fusing -and cutting through the structural ironwork and girders, to the filling -up of blowholes in castings. The metal to be welded is connected to one -pole, and the electrode handled by the operator forms the other pole, an -arc being struck between the two. Broken castings and forgings can be -satisfactorily repaired by running new fused metal round them. - -Recently the arc system has been applied with success for making welds -on tramway rails, the resistance of the welded joint being found very -much lower than when made with the usual fishplates and bonded joints. -Continuous current gives better results than alternating for the arc -system, and a generator designed for use with this process has a -“drooping characteristic,” that is, the volts at the terminals fall -rapidly with an increase in the current output. In this way the current -is automatically limited to some extent, when the short-circuiting -effect of the operation comes into play. Successfully to weld by this -process a current of 300 to 500 amperes at 80 volts is necessary, and -every precaution has to be taken to protect the workman from the intense -glare of the arc. - - -=Thermit.=--Thermit is an aluminium alloy whose combustion generates so -much heat that the substance can be used for the welding of iron and -steel. It is the patented invention of Dr. Hans Goldschmidt. With -thermit as a means of melting and welding, and with the use of special -clamps and devices, a number of operations, otherwise difficult, can be -performed, and thermit has come into general use for repairing broken or -defective parts. By the use of a portable jacket and clamp, the joints -of gas, water, and steam pipes may be welded with the pipes in position; -and the advantages of such a material to an engineer far removed from -supplies and repair shop, as at sea, can hardly be enumerated. New -journals have been welded to heavy rolls, broken pump-rods have been -joined, and a number of structural parts successfully united by its -aid. - -Thermit is made up as follows: Iron oxide is intimately mixed up with -about one-third as much in weight of powdered aluminium, according to -the equation Fe_{2} O_{3} 2 Al = Al_{2} O_{3} 2 Fe. The metals to be -united are placed together and surrounded by a little clay or similar -substance and the mixture is placed all around the joint. The mixture is -fired by a little magnesium, and the chemical change that follows -creates such an intense heat that iron is readily welded. When the joint -is cold and cleaned up it is hardly perceptible. - -According to instructions published by Thermit, Ltd., it is of the -utmost importance that the moulds, crucibles, etc., should be kept -thoroughly dry, and they may advantageously be warmed before use to -ensure the absence of any dampness. The parts to be welded must -previously be brought to red heat, which is best effected by means of a -gas and air flame. The proper design of the mould is of the utmost -importance. It should have a runner and riser, and the metal should be -allowed to flow between as well as around the ends of the pieces to be -welded. The expense and inconvenience of making wooden patterns may be -obviated by making the model of wax, ramming the sand round this, and -subsequently melting out the wax. - - - - -CHAPTER XVI - -Oxy-Acetylene Welding - - -Of late years oxy-acetylene welding and cutting have made great strides, -and have placed at the disposal of the metal-working trades a means of -doing many things that hitherto were impossible. Purified acetylene and -oxygen, both under pressure, are supplied to a special blowpipe or -torch. The flame in its hottest part has a temperature of about 4,000° -C. and is therefore sufficiently high to melt any metals with which it -may be brought into contact. The torch is fitted with all necessary -adjustments to vary the supply of either of the gases, and constitutes a -handy tool with which the intelligent worker soon acquires great -dexterity. In a special form of the torch there is a means of -introducing a further supply of compressed oxygen, which makes it -possible for the blowpipe flame to cut its way rapidly through thick -metal, the particles of which are actually consumed in the path of the -oxygen. - -It is out of the question in a single chapter of a handbook covering -such a large scope as the present work to do more than indicate some of -the uses to which the oxy-acetylene torch or blowpipe may be put. This -chapter is obviously no attempt whatever at providing a complete working -guide to oxy-acetylene welding. All that will be here attempted is to -present a brief description of a typical outfit and some notes on -working the blowpipe, and then to give some practical instruction from -the pen of an oxy-acetylene welder on the treatment of copper, aluminium -and cast-iron. It may here be pointed out that there is now a large -number of firms specialising in the manufacture of oxy-acetylene -welders’ appliances, and most of them publish illustrated catalogues -which anyone proposing to equip himself for oxy-acetylene welding would -do well to obtain. - -The source of the oxygen used in welding is now always cylinders, which -are obtainable in various sizes, either by purchase or on hire from the -gas-compressing companies, to whom they have to be returned for -recharging. The acetylene also can be had in the compressed form, but in -this case the gas is not simply compressed into steel cylinders because, -if it were, any simple shock would be likely to cause explosion. The -acetylene is therefore dissolved in liquid acetone, the cylinders -containing some porous substance such as fossil meal, which is saturated -with the acetone and the acetylene then pumped in. These also can be -bought or hired from the gas-compressing companies. A tremendous amount -of welding is done, however, with acetylene generated on the spot, and -there are on the market quite a number of approved appliances that can -be recommended, the best form of generator being that in which the -calcium carbide is dropped into the water instead of the water dripping -into the charge of calcium carbide. It is essential that the gas be -purified before use. As most people doubtless know, acetylene is one of -the hydro-carbon series of gases and is evolved by the action of water -on calcium carbide, a substance which is one of the products of the -electric furnace. - -[Illustration: Fig. 72.--Diagram of Oxy-acetylene Welding Apparatus] - -The particulars and instructions on pp. 136 to 139 are due to the -Acetylene Corporation, Ltd. Fig. 72 presents a diagrammatic illustration -of a complete oxy-acetylene blowpipe equipment with the exception of the -acetylene generator and holder, which apparatus may be placed in any -suitable position (preferably outside) at any reasonable distance from -the blowpipe. A is an ordinary gas tap connecting the hydraulic back -pressure valve B with the acetylene supply pipe from the acetylene -holder. The blowpipe is connected at valve C by means of a flexible tube -with the outlet tap D of the hydraulic back-pressure valve. This forms -the acetylene supply pipe to the blowpipe. The blowpipe is connected at -valve E by means of a special canvas-covered strong rubber pipe with the -outlet tap F of the oxygen pressure regulator, which is fixed, as shown, -on the oxygen cylinder. G is a pressure gauge. This pipe conveys the -oxygen supply to the blowpipe, and should be securely attached, as it is -subject to pressures varying from 5 lb. to 40 lb. per sq. in. The -hydraulic back-pressure valve should have been previously charged with -water, and the gas regulator screwed into the oxygen cylinder. The -blowpipe apparatus is now ready for use, with the taps A and D closed -and the taps C, E and F open. - -First, slowly open the oxygen cylinder valve (not shown) with the key -supplied for that purpose. By means of the thumb-screw H, adjust the gas -pressure to the correct working pressure for the blowpipe used. The -approximate pressure of oxygen required for each blowpipe is as follows: -No. 2, 8 lb. per sq. in.; No. 3, 10 lb.; No. 4, 11 lb.; No. 5, 12 lb.; -No. 6, 14 lb.; No. 7, 16 lb.; No. 8, 19 lb.; No. 10, 20 lb.; No. 12, 25 -lb.; No. 15, 30 lb. Then open the acetylene taps A and D, and when -acetylene is unmistakably smelt at the nozzle of the blowpipe, ignite -the gases by means of a gas jet, candle, or taper. Then by means of the -tap C slowly throttle down the acetylene until the small white cone of -flame at the nozzle of the blowpipe shows a clearly defined outline. As -some indication of the correct size of the cone, it may be mentioned -that when working with the No. 10 blowpipe this should be about 1/4 in. -diameter by 5/8 in. long. This cone in the other blowpipes is greater -or less according to the relative size. - -The tap A must never be used to regulate the supply of acetylene; in -fact, after the hydraulic back-pressure valve has been charged with -water, it is best to leave this tap always on. - -The working pressure for oxygen previously given should not be too -rigidly adhered to. Even in the same sizes of blowpipes the conditions -must vary slightly, and a little practical experience with each blowpipe -will soon indicate the best working conditions. If the flame is not -properly regulated it may fire back and go out. If so, the taps C and E -should be shut off at once, and a few seconds allowed to elapse before -relighting. When work is carried on for a long time at a stretch and the -burner becomes warm, it will be found necessary to slightly open the -acetylene tap C from time to time. If work is being done which involves -the nozzle of the blowpipe being held in a confined space, it is -advantageous to cool this end of the blowpipe by immersing it from time -to time in a bucket of water. While this is done the gases must be -turned off at C and E. - -Welding should be done at the apex or outer extremity of the small white -cone. - -If the hole in the nozzle of the blowpipe gets obstructed at any time -through beads of iron being splashed into it, or from any other cause, -it may be cleared with a piece of copper wire and cleaned with a wire -brush. No steel reamer or other sharp instrument should be used in the -hole, which otherwise will be altered in size. - -On stopping work the acetylene tap C should be closed first and then the -oxygen tap E. When work is completely stopped, the oxygen cylinder -should be shut off. The oxygen cylinder valve should never be opened -until taps F and E are open, and it should then be opened slowly. In -this way sudden impact of oxygen in the regulator is obviated. - -The following instructions on the methods of welding copper, cast-iron -and aluminium are contributed by a foreman welder. - - -=Welding Copper.=--Copper to be welded should have its edges bevelled to -enable the welding to penetrate the entire thickness of the metal. -Bevelling is not generally practised below a thickness of 3/32 in. From -3/32 in. to 3/16 in., a slight open bevel is sufficient; 3/16 in. thick -and over, the angle of the bevel should be about 90°. It is not -necessary to go beyond this even with great thickness. The bevelling -should be regular, especially at the bottom, so as not to produce holes -or excess of thickness at the bottom of the bevel. - -The edges to be welded and their immediate neighbourhood should be -thoroughly cleaned. This can be done with a file, scraper, or sheets of -emery. Chemical agents such as spirits of salt or nitric acid are -sometimes employed; but it is preferable to precede their use by a -mechanical cleaning. - -Before beginning the welding the parts should be carefully arranged so -that during the welding operation they remain perfectly in position. -Owing to the high conductivity of copper, a relatively larger blowpipe -tip must be used than when welding either iron or mild steel of the same -thickness. The power of a blowpipe of 225 litres with an approximate -consumption of 7·75 cub. ft. of acetylene per hour would be suitable, -with economical results, for iron or mild steel 1/8 in. thick, whereas -for copper of the same thickness the power of the blowpipe should be of -300 litres, having an approximate consumption of 10·5 cub. ft. of -acetylene per hour. Also, a blowpipe which is too strong tends to melt -the metal too rapidly. This should be as carefully avoided as that of -melting too slowly. - -A pure copper welding rod may be employed for filling in, but it is not -so effective as a welding rod made of phosphor copper. The phosphorus is -incorporated in a very small quantity, so that none remains in the weld -after its execution. A filler rod which contains too much phosphorus -lacks fluidity, and melts at a temperature much lower than that of the -copper to be welded, thus facilitating adhesion. Moreover, the welds in -which the phosphorus remains lack elongation, and therefore do not -possess the same mechanical properties as pure copper. The welding rod -after 1/16 in. of its diameter should be about equal to the thickness of -the weld, although in practice feeders about 1/4 in. in diameter are not -generally employed. Welds made on copper without a deoxidising welding -rod properly prepared have a tendency to oxidise, and therefore do not -possess the required qualities. In addition, the surface of the metal -must be covered with a carefully prepared mixture of potassium phosphate -and potassium carbonate to a depth of about 1/16 in. Upon the -application of the flame, the mixture will melt and form a glaze over -the surface of the copper, thus preventing oxidation and assuring good -work. - -A flux consisting of chloride of sodium, sodium borate, and boracic acid -is also recommended. The flux should be sparingly applied by dipping the -end of the welding rod into the vessel containing the flux. The end of -the rod should be warmed in order that the flux adheres. - -Before beginning the actual operation of welding, it is essential to -raise the edges of the weld and the parts in the vicinity to a high -temperature. The high conductivity of the metal necessitates this, as -any supply of molten welding rod before the edges are in a molten state -inevitably produces adhesion. The flame of the blowpipe should be -perfectly regulated and maintained without excess of either acetylene or -oxygen. In executing the weld, care must be taken to avoid contact of -the white jet of the blowpipe flame with the metal just about to be -melted. The distance of the white jet should vary according to the power -of the blowpipe, say from 3/16 in. to 3/8 in. If this distance is -increased, the gases resulting from the second phase of combustion, -carbonic acid and water vapour, influence the weld. Care must be taken -that the fusion of the metal should not be undertaken until the edges of -the weld and the parts near have been raised to a high temperature. At -this moment the welding rod and the parts to be joined should be melted -simultaneously. It is essential that the welding rod should be regularly -incorporated in the line of welding, and must not be allowed to fall in -drops. The operation should be continuous, taking care to attack -regularly the two edges of the metal. The welding is thus executed -rapidly. - -It is well known that internal strains are always set up in every -process of welding, due to the expansion and contraction when a metal is -heated and cooled. Copper lacks tenacity when heated; hence contraction -of the metal, whose coefficient of expansion is also fairly high; -fractures thereby are often produced, especially in the welded part. -However, pre-heating the article to a high temperature, maintaining the -heating after the operation of welding and slow cooling, enables one in -many cases to avoid fractures due to contraction. It is also necessary -to hammer the line of welding and its vicinity. After the hammering -operation it is essential to reheat the copper, raising it to redness -(500° C. to 600° C.). Then plunge into cold water, or cool as rapidly as -possible. The structure of the weld is not quite as homogeneous as other -parts of the piece welded. This is, however, controlled largely by the -skill and workmanship of the operator, who can, at will, make the weld -more or less homogeneous. - -It is impossible to enumerate in anything like detail all the work in -copper which may be executed by oxy-acetylene autogenous welding. -However, copper-smiths are advantageously making great use of the -system, thereby replacing their old methods of brazing and riveting. - - -=Welding Aluminium.=--In preparing aluminium to be welded, the edges -must first be thoroughly cleaned and the welding rod very pure, so as to -avoid the incorporation of impurities, which is apt to bring about rapid -disintegration in the line of welding. Bevelling the edges to be joined -is not necessary below a thickness of 1/8 in. From 1/8 in. to 3/16 in. a -slight open bevel is sufficient, 3/16 in. thick and above angle of bevel -should be about 90°. For thin sheets up to a maximum of 3/32 in., -welding is facilitated by flanging the edges at right angles. The depth -of the flange should be slightly deeper than the thickness of the metal. -By this method no welding rod is required, the edges being simply fused. -The weld should afterwards be hammered level. - -Aluminium should never be welded without a flux. If welding is attempted -without a flux, globules consisting of aluminium within and a coating of -alumina (oxide of aluminium) will appear. In order to eliminate these by -the blowpipe flame it would be necessary to raise the temperature to the -melting point of the oxide of aluminium, which is nearly 3,000° C., -whilst the melting point of metallic aluminium is only 657° C. To -produce a flux which will dissolve the oxide at the low melting point of -the metal and at the same time protect the hot metal from contact with -the air has obviously not been a simple problem to the chemist and -engineer. However, several good fluxes are now obtainable which enable -any experienced welder to effect satisfactory welds in aluminium. - -A flux consisting of the following ingredients can be recommended: -sodium chloride 30 parts, potassium chloride 45 parts, lithium chloride -15 parts, potassium fluoride 7 parts, and bisulphate of potassium 3 -parts. - -When making fluxes for the welding of aluminium, great care is necessary -in order to completely dry the ingredients, thus avoiding their -combination with each other. On aluminium above 3/32 in. thick, the flux -is best applied by dipping the end of the welding rod into the vessel -containing the flux. The end of the rod should be first warmed in order -that the flux adheres. The welding rod after 1/16 in., its diameter -should be just about equal to the thickness of the weld, although in -practice feeders above 1/4 in. diameter are not advisable. - -In executing the weld, care must be taken to avoid contact of the white -jet of the blowpipe flame with the metal just about to be melted, -because the high temperature of this part tends to produce holes which -are difficult to fill in. The distance of the white jet should vary -according to the power of the blowpipe, say from 1/4 in. to 3/4 in. The -flame should be so adjusted as to furnish an excess of acetylene. There -need be but little fear of carbonising the metal, for the reason that -the temperature of the work is comparatively low. For thin welds, up to -1/8 in. thick, it is preferable to hold the welding rod in front of the -blowpipe in the direction of the edges to be welded. As soon as the -latter begins to melt it is heated rapidly, and should be lowered to -form one molten bath with the metal of the piece. The welding is thus -done very rapidly. For great thicknesses it is preferable to obtain -fusion of the welding rod, previously heated in the molten bath of the -bevel. Directly after welding, the weld should be thoroughly washed in -clean warm water in order to remove all remaining traces of the flux, -which would otherwise continue to have a chemical action on the metal, -thereby setting up corrosion. - - -=Welding Cast-Iron.=--The edges of the weld should be bevelled when the -thickness exceeds 1/8 in.; this enables the welding to penetrate the -entire thickness of the metal. Both edges must be bevelled to an angle -of 45°, so as to form a right angle at the weld. The bevelling should be -regular, especially at the bottom, so as not to produce holes or excess -thickness at the bottom of the bevel. Workers who attempt to effect -welds on cast-iron above, say, 1/4 in. in thickness, without bevelling, -invariably obtain poor results, as it is impossible to get regular and -thorough penetration. The bevelling of the edges may be done by chipping -or grinding, etc. Grinding wheels made from a carbide of silicon -abrasive are very effective for cast-iron. The edges to be welded and -their immediate neighbourhood must be free from sand, dirt, and rust. - -It is known that internal strains are always set up in every process of -welding, due to the expansion and contraction when a metal body is -heated and cooled. These strains are not unavoidable, but their effect -may be minimised or nullified. In the case of cast-iron, the tendency to -crack will be greatly increased if the cooling of the metal after fusion -is rapid or irregular. Consequently, the article to be welded should be -pre-heated slowly to about 700° F. to 1,000° F. Generally speaking, the -higher the temperature of pre-heating, the less the danger of cracking. -Preferably, pre-heating and subsequent slow cooling should be carried -out in a muffle, particularly where light and intricate castings have to -be dealt with. - -In all cases care should be taken in the selection of the proper size of -blowpipe tip to be used on any particular job. Therefore, the size of -tip recommended by the manufacturers should be employed. The total heat -of fusion of cast-iron being high, it is necessary to use a blowpipe -with a greater power than for the same thickness of welds on mild-steel -or wrought-iron. In the actual operation of welding, the blowpipe flame -should be played on the edges to be welded until the melting of the iron -just takes place. It is essential to avoid contact of the white cone of -the blowpipe flame with the metal just about to be melted; the point -should be kept at a distance varying from 3/16 in. to 3/4 in., according -to the thickness of the work. The two edges to be joined should melt -simultaneously. As soon as the first fusion is obtained, a little flux -or scaling powder must be added; this is usually applied by dipping the -extremity of the welding rod into the vessel containing the flux, the -rod having been previously heated. Avoid throwing the powder into the -molten metal whilst executing the weld, as the supply from the welding -rod is always sufficient. - -Many kinds of fluxes for cast-iron are furnished by the manufacturers of -welding apparatus, which vary considerably in composition. The principle -of all of them is to provide some chemical which, at the high -temperature involved, will break up the oxide into its component parts. -The following combinations will perform these functions, and can be -recommended: (1) Boracic acid 80 parts, powdered chlorate of potash 20 -parts, ferric carbide 15 parts. (2) Equal parts of carbonate and -bicarbonate of soda, to which is added from 10 to 15 per cent. of borax -and 5 per cent. of precipitated silica. (3) Carbonate of soda 50 per -cent. and bicarbonate of soda 50 per cent. The necessity for using a -flux may not be thoroughly appreciated; but if it is attempted to weld -cast-iron without it difficulty will at once be experienced. - -Do not add any metal from the welding rod until the bottom of the [V] is -filled from the sides. It is found that by employing silicon in the -welding rod, in the form of ferro-silicon, the iron combines with the -silicon in preference to the carbon, allowing the carbon to take the -form of graphite, and thus facilitate the formation of grey iron. The -welding rod should contain about 4 per cent. of silicon and as low as -possible in manganese. The purchase of such a welding rod is not at all -difficult, and may be obtained from the same manufacturers as the flux, -from 1/8 in. to 1/2 in. in diameter. - -One criticism of cast-iron welding has been directed against the -hardness of the weld. This hardness may be due to a number of causes, -such as inefficiency of the operator, unsatisfactory fluxes and welding -apparatus, rapid cooling, etc. Therefore, as stated previously, in order -to get good workable welds, there must be slow cooling after the welding -is complete; and there is no reason why the worker who carefully follows -the instructions given, and applies himself diligently to the task, -should not be able to weld cast-iron of any thickness in an efficient -and workmanlike manner. - -This method of welding cast-iron successfully solves an unlimited -variety of manufacturing and repair problems in the engineering -industry, and can be relied on to make homogeneous welds on cast-iron. -It is impossible to enumerate in anything like detail all the work in -cast-iron which may be executed by oxy-acetylene welding; but the -following are some of the applications for which it has already been -advantageously employed: For repairing broken machine parts, gear boxes, -motor cylinders, crank cases, tanks, manifolds, flywheels, etc., filling -blowholes and defects in castings. Castings impossible or difficult to -mould can be made in parts and united. Teeth broken from gear wheels can -be renewed, and adding metal in any desired quantity to worn parts of -cast-iron articles. As a concrete example of its economical and positive -aid to the engineering industry, the following may be of interest. A -cast-iron belt-wheel would have gone on the scrap heap, a total loss, -with four of the six spokes broken, three entirely out. It was 5 ft. in -diameter, and weighed about 500 lb., but was not worth much as scrap -metal. Scrapping it meant the purchase of a new wheel, and perhaps a -long delay in getting one cast. But with the oxy-acetylene process the -three spokes that were fractured were welded into place; the fourth -spoke broken near the hub was also welded. There were seven welds, each -about 1-1/2 in. by 4 in.; the job was done profitably at a cost of £5, -ready for delivery in two days, and was considerably better than buying -a new wheel, and waiting two weeks or two months for delivery. The -process is particularly suitable for this class of work, and cannot fail -to give satisfaction if performed by an experienced welder. The cost of -welding a given job depends not only on its thickness, but on the skill -of the workman. For example, the same class of job may vary as much as -50 per cent. if executed by different operators. - - - - -CHAPTER XVII - -Lead Burning - - -Lead-burning or flaming is the autogenous welding of lead by means of -either an aero-hydrogen or oxy-coal-gas blowpipe flame. In the past the -apparatus required included a hydrogen-gas generating chamber (called -the “lead-burning machine”) and a blower or air chamber. The hydrogen -was made by the action of dilute sulphuric acid on zinc. That system is -now, or should be, obsolete, having been superseded by the cleanly and -altogether more convenient process of employing two cylinders, one of -compressed coal-gas and the other of compressed oxygen, in conjunction -with an injector-pattern blowpipe. Gauges and regulators are required as -in the oxy-acetylene process. - -The oxy-acetylene process may be successfully applied to lead-burning in -spite of the great heat of such a flame. The consumption of acetylene, -according to Mr. D. Richardson’s translation of Granjon and Rosenberg’s -French work, is only 1 to 2 cubic feet per hour for lead 1/16 in. to -3/16 in. thick, and the process is stated to have “considerable -advantages over all other methods of autogenous soldering.” - -In lead-burning it is customary to employ a triangular stick of refined -lead for filling up the seams. By being burnt or joined together in -this way, the lead becomes homogeneous, and the various parts of it -equally withstand the same chemical action and heat. For this reason it -is used for joining the seams of chemical and acid tanks, and for the -joints of pipes used for the conveyance of such chemicals. Solder being -an alloy, the acid would have a solvent action on it, eating it away and -rendering it useless, and it would also give rise to electrical action, -practically impossible when only one metal is exclusively employed. -Lead-burning is also often used on external or roof work. - -The seams burnt on sheet-lead are of two kinds: one forming a butted -joint, the other a lapped joint. - -In burning a butted seam, the two edges of the lead to be joined are -butted together, and shaved about 1/4 in. to 3/8 in., or slightly less, -on each side. The gas and oxygen are turned on and adjusted so as to -produce a flame from about 5 in. to 6 in. long, and tapering to a fine -point. The hottest part of the flame is the centre of the thickest -portion, about 1 in. or 1-1/2 in. from the jet. Hold the jet in the -right hand, and a strip of lead in the left, and allow the flame to play -on the end of the strip, which is held just above the seam. As the strip -melts, the jet is diverted on to the seam so as to fuse the edges -together, the additional lead forming a thickened portion. The strip is -again melted, and joined to the edges, and also to the thickest part; -and so on along the length. Care should be taken to burn the lead -through, but not for the metal to flow beneath the seam. After a little -practice, the operator will know exactly when to apply and when to -remove the jet. - -Fig. 73 shows a flat butted joint partly burnt. The stick of lead is -just nipped with the flame, and a bead of lead dropped on the seam. The -flame is then directed on to this bead until it is fused with the seam. -When bead and seam are melted together, the flame is immediately raised. -The next bead of lead is then dropped on the seam so as to half cover -the previous bead, as shown at M (Fig. 73). The flame is then directed -on the second bead, the flame being immediately raised after these are -fused together, and this operation is repeated until the whole of the -seam is burnt. - -A flat lapped joint, partly burnt, is shown by Fig. 74. In burning this -joint, the stick of lead is only required to fill up any irregularities -in the burning, and is not required to form the seam in the same way as -it is in a butted joint, because in lapped burning the overcloak is -burnt down on to the undercloak, as shown in Fig. 75. In horizontal and -vertical burning, lapped joints only should be used. - -Fig. 75 shows a specimen of horizontal or side burning, and Fig. 76 one -of vertical or upright burning. In burning both of these, the stick of -lead is not required at all, the overcloak being in each case burnt down -on to the undercloak. Care must be taken that both the overcloak and -undercloak of a lapped joint are well shaved. - -[Illustration: Fig. 73.--Butted Seam Partly Burnt] - -[Illustration: Fig. 74.--Lapped Seam Partly Burnt] - -[Illustration: Fig. 75.--Horizontal or Side Burning] - -[Illustration: Fig. 76.--Vertical or Upright Burning] - -[Illustration: Fig. 77.--Burning Upright Joint] - -[Illustration: Fig. 78.--Branch Joint Ready for Burning] - -The seams should not be soiled or greased, and care must be taken not to -tarnish them in any way. If the lead is not shaved quite clean, or it -becomes tarnished after it is shaved, it will be found difficult to burn -it together successfully. No tallow or smudge is necessary. The operator -will soon detect the presence of any foreign substance or dirt on the -lead, and the shavehook should be kept handy to remove it. - -In burning a vertical lapped seam, starting at the bottom, the lapping -lead is melted, and as it runs is turned on to the back portion and -fused into it. A slight projection is formed, which holds the next -melting, and so on, each layer forming a base for the next, and adding -to the height until the top is reached. - -In practising either horizontal or vertical burning, the student should -first place his work at an easy angle--say, at about 25° or -30°--gradually raising it as he becomes proficient until the seam is in -a horizontal or vertical position as desired. Two surfaces can be burned -together in any position--horizontal, vertical, or even overhead, where -soldering would be impossible. - -Pipe joints can also be made by burning. First one pipe is opened to -form a socket like a slip joint. The male part, which must enter at -least 3/4 in., must be well shaved and made to fit tight. Fig. 77 shows -an upright joint prepared and partly burnt. Fig. 78 shows a section of a -branch joint as prepared for burning. Care must be taken to work up a -good thick shoulder for the socket N. - - - - -INDEX - - - Acetylene used in welding, 135 - Alloys, eutectic, 4 - Aluminium, bit used with, 61 - ----, difficulty in soldering, 57, 58 - ----, flux for, 61, 143, 144 - ----, oxy-acetylene welding, 143 - ----, soldering, 62, 63 - ---- solders, 58-61 - Arc welding, 131, 132 - Autogenous welding (_see_ Oxy-acetylene welding) - - “Best” solder, 4 - Birdcage wires, soldering, 53 - Bismuth, solder and flux for, 7 - Black, plumber’s, 66-68 - Blow-lamp bit, 21 - Blow-lamps, 44, 46, 92 - ----, managing, etc., 118-121 - ----, paraffin brazing, 122-128 - Blowpipe, bench, 40, 41 - ----, Black’s, 37 - ---- capacities, 116 - ---- flame, 38 - ----, Fletcher’s, 37 - ----, gas, making, 93, 94 - ----, mouth, 37-40 - ----, operating, 46 - ----, oxy-acetylene, 136 - ----: proportion of air to gas, 114 - ---- soft solder, 4 - ---- soldering, 17, 46-56 - Boiling water, solders that melt in, 11 - Borax flux, 78, 79 - Brass fittings, tinning, 66 - ----, solder and flux for, 7 - ----, soldering aluminium to, 60 - Britannia metal, solder and flux for, 7 - Brazing, 1, 89-107 - ---- copper rod, 100 - ---- cycle-frame joints, 103 - ----, flux for, 91 - ---- iron, 98-100, 105-107 - ---- key stems, 101 - ----, spelter for, 89-91 - ---- steel, 98-100 - Brazing-lamps (_see_ Blow-lamps) - Brooches, soldering, 83 - Brush for applying flux, 14 - Bunsen burner, 40, 42 - Burning lead, 2, 150-154 - - Cast-iron, brazing, 105-107 - ----, flux for, 106, 107, 147 - ----, oxy-acetylene welding, 145 - Catching-tray, 42 - Churns, soldering, 35 - Clay, packing work in, 51 - Cloths, plumber’s, 68, 69 - “Coarse” solder, 4 - “Common” solder, 4 - Compo. piping, making solder from, 9 - Contact welding, 129-131 - Copper, brazing, 100 - ----, flux for, 141 - ----, oxy-acetylene welding, 139 - ----, soldering aluminium to, 60 - ----, soft solder and flux for, 7 - Copper-bit soldering, 28-36 - Copper-bits, 17-24 - ----, gas-heated, 22-24 - ----, holding, 30 - ----, spirit-heated, 20, 21 - ----, stoves for, 24, 25 - ----, tinning, 25-28 - Corroded metal, soldering, 50 - Cycle brazing, 102-105 - - Dial ring, soldering, 50 - Dross on solder, 11 - - Electric arc welding, 131, 132 - ---- contact welding, 129-131 - Enamelled ware, soldering, 35 - Eutectic alloys, 4 - - “Fine” solder, 4 - Flaming lead, 2, 150-154 - Flux (_see also names of metals_) - ----, applying, 14, 15 - ---- for brazing, 91 - ---- combined with solder, 10 - ---- containers, 14 - ---- for soft soldering, 12-16 - Fluxite and specialities, 13, 20 - Food containers, flux for, 15 - Fusion welding (_see_ Oxy-acetylene welding) - - Galvanised steel, solder and flux for, 7 - Gas blowpipes, 41, 93, 94, 112-117 - ---- brazing-hearth, 94-98 - Gas-heated bits, 22-24 - Gold, “colouring,” 87, 88 - ----, flux for, 7 - ---- jewellery, soldering, 83-88 - ---- solders, hard, 85, 86 - ---- ----, soft, 7 - Gold-cased ware, soldering, 84 - Granulated solder, 8 - Gun-barrel, soldering catch on, 36 - Gunmetal, solder and flux for, 7 - - Hard solder and soldering (_see_ Brazing, Silver-soldering, _and names - of metals_) - Hardness of solder, 5 - Hearth, gas brazing, 94-98 - Hiorns, A. H., 4, 5 - - Iron, brazing, 98-100, 105-107 - ----, flux for, 147 - ----, hammer-welding, 108 - ----, oxy-acetylene welding, 145 - ----, soft solder and flux for, 7 - - Jewellery, soldering, 83-88 - Joints, reinforced and filled-in, 34 - Jubb, W. H., 76 - - Kettle spout, soldering, 50 - Key stems, brazing, 101 - “Killed spirit,” 12-15 - - Lading-can handle, soldering, 47 - Ladle, solder, 7 - Lamp, soldering lug on, 48 - Lead, solder and flux for, 7 - Lead-burning, 2, 150-154 - Leaded lights, soldering, 35 - - “Magic” solder, 10 - “Medium” solder, 4 - Melting points of solder, etc., 4, 5 - Milk churns, soldering, 35 - - Name-plates, sweating letters on, 54-56 - Oxy-acetylene welding, 2, 134-149 - ---- ---- aluminium, 143-145 - ---- ----: apparatus, 136-139 - ---- ---- cast-iron, 145-149 - ---- ---- copper, 139-143 - Oxygen used in welding, 135 - - Paillons, solder, 79-80 - Pewter, making solder from, 9 - ----, solder and flux for, 7 - Phosphor-tin, solders containing, 59-61 - Pickle, gold-solderer’s, 85, 87 - ----, silver-solderer’s, 77, 78, 87 - Pipe joints, burnt, 153, 154 - ---- ----, horizontal or underhand wiped, 69-72 - ---- ----: lead to cast-iron, 74 - ---- ----, silver-soldered, 80, 81 - ---- ----, soldered, 52, 53 - ---- ----, upright wiped, 72-74 - Plumber’s black, 66-68 - ---- cloths, 68, 69 - ---- flux, 66 - ---- solder, 4, 64-66 - “Poisoned” solder, 6, 65, 66 - - Rings, jewelled, soldering, 84 - Ryan’s gas-heated bit, 22 - - Sal-ammoniac block for tinning bits, 26-28 - Sand, packing work in, 51 - Seams, soft-soldered, 31-33 - Shave-hook, 28 - Silver jewellery, soldering, 83 - ----, soft solder and flux for, 7 - ---- solders, 75-77 - Silver-soldering, 1, 3, 75-82 - ----: pickle, 77, 78 - ----: quenching, 81 - ----: removing marks, 81 - Smudge, plumber’s, 66-68 - Soft soldering, 1-3, 28-56 - ---- ---- with blowpipe, 46-56 - ---- ---- ---- copper-bit, 28-36 - ---- solders, 4-11 - ---- ---- that melt in boiling water, 10, 11 - Soil, plumber’s, 66-68 - Solder (_see also_ Silver solder, Soft solder, etc., _and under names - of metals_) - ---- combined with flux, 10 - ----, overheated, 11 - ----, re-melted, 11 - “Soldering iron,” 17 - Soldering solutions, 14 - Spelter, 1, 3, 89-91 - Spirit-heated bits, 20, 21 - Spirit-lamps, 40 - Spot-welding, electric, 130 - Steel, brazing, 98-100 - ----, flux for, 111 - ----, hammer-welding, 109-111 - ----, soft solder and flux for, 7 - Stoves for heating bits, 24, 25 - Strip solder, 6-8 - Sweating, 32-34, 54-56 - - Tapers, 41 - Tears, solder, 8 - Thermit welding, 2, 132, 133 - Tin, solder and flux for, 7 - Tinning bits, 25-28 - “Tinol” specialities, 10, 13, 19 - Tinplate, solder and flux for, 7 - “Touch” or tallow, 66 - Tube solder, 10 - - Vegetable masher, soldering, 48 - “Very fine” solder, 4 - - Watch-case, silver-soldering, 79 - Welding (_see also separate headings_) - ----, electric, 129-132 - ---- iron and steel under the hammer, 108-111 - ----, oxy-acetylene, 134-149 - ----, thermit, 132, 133 - ----: various processes, 1, 2 - Wire, solder, 8 - - Zinc chloride, 12-15 - ---- in solder, 6, 65, 66 - ----, solder and flux for, 7 - - -PRINTED BY CASSELL & COMPANY, LIMITED, LA BELLE SAUVAGE, LONDON, E.C. - - - - - Transcriber’s Notes - - - Inconsistencies in the source document have been retained. - - Depending on the hard- and software used, not all elements may display - as intended. - - Page 59, table: the row Tin 6 does not add up to 100 (%, presumably) - as the other rows do. - - Minor obvious punctuation errors have been corrected silently. - - Page 5: 66° and 34° have been changed to 66% and 34%, respectively. - - Page 7: flow over the hoe has been changed to flow over the hole. - - Page 154: enter at last has been changed to enter at least. - - - - - -End of Project Gutenberg's Soldering, Brazing and Welding, by Bernard E. Jones - -*** END OF THIS PROJECT GUTENBERG EBOOK SOLDERING, BRAZING AND WELDING *** - -***** This file should be named 52074-0.txt or 52074-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/5/2/0/7/52074/ - -Produced by deaurider, Harry Lamé and the Online Distributed -Proofreading Team at http://www.pgdp.net (This file was -produced from images generously made available by The -Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. Special rules, -set forth in the General Terms of Use part of this license, apply to -copying and distributing Project Gutenberg-tm electronic works to -protect the PROJECT GUTENBERG-tm concept and trademark. Project -Gutenberg is a registered trademark, and may not be used if you -charge for the eBooks, unless you receive specific permission. If you -do not charge anything for copies of this eBook, complying with the -rules is very easy. You may use this eBook for nearly any purpose -such as creation of derivative works, reports, performances and -research. They may be modified and printed and given away--you may do -practically ANYTHING with public domain eBooks. Redistribution is -subject to the trademark license, especially commercial -redistribution. - - - -*** START: FULL LICENSE *** - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full Project -Gutenberg-tm License (available with this file or online at -http://gutenberg.org/license). - - -Section 1. General Terms of Use and Redistributing Project Gutenberg-tm -electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or destroy -all copies of Project Gutenberg-tm electronic works in your possession. -If you paid a fee for obtaining a copy of or access to a Project -Gutenberg-tm electronic work and you do not agree to be bound by the -terms of this agreement, you may obtain a refund from the person or -entity to whom you paid the fee as set forth in paragraph 1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this agreement -and help preserve free future access to Project Gutenberg-tm electronic -works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" -or PGLAF), owns a compilation copyright in the collection of Project -Gutenberg-tm electronic works. Nearly all the individual works in the -collection are in the public domain in the United States. If an -individual work is in the public domain in the United States and you are -located in the United States, we do not claim a right to prevent you from -copying, distributing, performing, displaying or creating derivative -works based on the work as long as all references to Project Gutenberg -are removed. Of course, we hope that you will support the Project -Gutenberg-tm mission of promoting free access to electronic works by -freely sharing Project Gutenberg-tm works in compliance with the terms of -this agreement for keeping the Project Gutenberg-tm name associated with -the work. You can easily comply with the terms of this agreement by -keeping this work in the same format with its attached full Project -Gutenberg-tm License when you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are in -a constant state of change. If you are outside the United States, check -the laws of your country in addition to the terms of this agreement -before downloading, copying, displaying, performing, distributing or -creating derivative works based on this work or any other Project -Gutenberg-tm work. The Foundation makes no representations concerning -the copyright status of any work in any country outside the United -States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other immediate -access to, the full Project Gutenberg-tm License must appear prominently -whenever any copy of a Project Gutenberg-tm work (any work on which the -phrase "Project Gutenberg" appears, or with which the phrase "Project -Gutenberg" is associated) is accessed, displayed, performed, viewed, -copied or distributed: - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - -1.E.2. If an individual Project Gutenberg-tm electronic work is derived -from the public domain (does not contain a notice indicating that it is -posted with permission of the copyright holder), the work can be copied -and distributed to anyone in the United States without paying any fees -or charges. If you are redistributing or providing access to a work -with the phrase "Project Gutenberg" associated with or appearing on the -work, you must comply either with the requirements of paragraphs 1.E.1 -through 1.E.7 or obtain permission for the use of the work and the -Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or -1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any additional -terms imposed by the copyright holder. Additional terms will be linked -to the Project Gutenberg-tm License for all works posted with the -permission of the copyright holder found at the beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including any -word processing or hypertext form. However, if you provide access to or -distribute copies of a Project Gutenberg-tm work in a format other than -"Plain Vanilla ASCII" or other format used in the official version -posted on the official Project Gutenberg-tm web site (www.gutenberg.org), -you must, at no additional cost, fee or expense to the user, provide a -copy, a means of exporting a copy, or a means of obtaining a copy upon -request, of the work in its original "Plain Vanilla ASCII" or other -form. Any alternate format must include the full Project Gutenberg-tm -License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works provided -that - -- You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is - owed to the owner of the Project Gutenberg-tm trademark, but he - has agreed to donate royalties under this paragraph to the - Project Gutenberg Literary Archive Foundation. Royalty payments - must be paid within 60 days following each date on which you - prepare (or are legally required to prepare) your periodic tax - returns. Royalty payments should be clearly marked as such and - sent to the Project Gutenberg Literary Archive Foundation at the - address specified in Section 4, "Information about donations to - the Project Gutenberg Literary Archive Foundation." - -- You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or - destroy all copies of the works possessed in a physical medium - and discontinue all use of and all access to other copies of - Project Gutenberg-tm works. - -- You provide, in accordance with paragraph 1.F.3, a full refund of any - money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days - of receipt of the work. - -- You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm -electronic work or group of works on different terms than are set -forth in this agreement, you must obtain permission in writing from -both the Project Gutenberg Literary Archive Foundation and Michael -Hart, the owner of the Project Gutenberg-tm trademark. Contact the -Foundation as set forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -public domain works in creating the Project Gutenberg-tm -collection. Despite these efforts, Project Gutenberg-tm electronic -works, and the medium on which they may be stored, may contain -"Defects," such as, but not limited to, incomplete, inaccurate or -corrupt data, transcription errors, a copyright or other intellectual -property infringement, a defective or damaged disk or other medium, a -computer virus, or computer codes that damage or cannot be read by -your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium with -your written explanation. The person or entity that provided you with -the defective work may elect to provide a replacement copy in lieu of a -refund. If you received the work electronically, the person or entity -providing it to you may choose to give you a second opportunity to -receive the work electronically in lieu of a refund. If the second copy -is also defective, you may demand a refund in writing without further -opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS' WITH NO OTHER -WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO -WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of damages. -If any disclaimer or limitation set forth in this agreement violates the -law of the state applicable to this agreement, the agreement shall be -interpreted to make the maximum disclaimer or limitation permitted by -the applicable state law. The invalidity or unenforceability of any -provision of this agreement shall not void the remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in accordance -with this agreement, and any volunteers associated with the production, -promotion and distribution of Project Gutenberg-tm electronic works, -harmless from all liability, costs and expenses, including legal fees, -that arise directly or indirectly from any of the following which you do -or cause to occur: (a) distribution of this or any Project Gutenberg-tm -work, (b) alteration, modification, or additions or deletions to any -Project Gutenberg-tm work, and (c) any Defect you cause. - - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of computers -including obsolete, old, middle-aged and new computers. It exists -because of the efforts of hundreds of volunteers and donations from -people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need, are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future generations. -To learn more about the Project Gutenberg Literary Archive Foundation -and how your efforts and donations can help, see Sections 3 and 4 -and the Foundation web page at http://www.pglaf.org. - - -Section 3. Information about the Project Gutenberg Literary Archive -Foundation - -The Project Gutenberg Literary Archive Foundation is a non profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Its 501(c)(3) letter is posted at -http://pglaf.org/fundraising. Contributions to the Project Gutenberg -Literary Archive Foundation are tax deductible to the full extent -permitted by U.S. federal laws and your state's laws. - -The Foundation's principal office is located at 4557 Melan Dr. S. -Fairbanks, AK, 99712., but its volunteers and employees are scattered -throughout numerous locations. Its business office is located at -809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887, email -business@pglaf.org. Email contact links and up to date contact -information can be found at the Foundation's web site and official -page at http://pglaf.org - -For additional contact information: - Dr. Gregory B. Newby - Chief Executive and Director - gbnewby@pglaf.org - - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without wide -spread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To -SEND DONATIONS or determine the status of compliance for any -particular state visit http://pglaf.org - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg Web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. -To donate, please visit: http://pglaf.org/donate - - -Section 5. General Information About Project Gutenberg-tm electronic -works. - -Professor Michael S. Hart is the originator of the Project Gutenberg-tm -concept of a library of electronic works that could be freely shared -with anyone. For thirty years, he produced and distributed Project -Gutenberg-tm eBooks with only a loose network of volunteer support. - - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as Public Domain in the U.S. -unless a copyright notice is included. Thus, we do not necessarily -keep eBooks in compliance with any particular paper edition. - - -Most people start at our Web site which has the main PG search facility: - - http://www.gutenberg.org - -This Web site includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. |