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Solder

Soldering is a process by which solid metallic substances are united by the intervention of a more fusible metal or solder, which, when placed between them and fused, unites the three parts into a solid mass; sometimes, however, the joining of two edges or surfaces may be accomplished by fusing or melting with the same metal. Solders are made of gold, silver, copper, tin, lead, bismuth, etc.; usually observing that in the composition there shall be some of the metal that is to be soldered, mixed with some higher and finer metals. The coppersmith's hearth, standing off from the wall, is a convenient fire for hard-soldering or brazing. The brazier's hearth is usually an iron plate with fire-box underneath; a convenient aperture in the plate allows the heat to play direct on the work as it rests on the table, the force being regulated by a fan-blast. For fine and complicated soldering, the blowpipe is best; the wind for which is sometimes obtained mechanically, but more commonly by blowing with the mouth. Jewelry manufacturers employ a trough or shoot of circular form, through which a gas flame is urged by means of a pair of ordinary bellows. The common blowpipe in the workshop is the oxyhydrogen, so arranged that it may be used at any desired angle.

Silver solder is usually employed for fine work in brass, iron, or steel, and the brazing is effected by laying thin plates of the solder on the joints, which have been previously moistened with borax and water. For gold and silver soldering, the borax is usually made into a creamy paste by rubbing with water and then painting over the parts to be joined. Solders of this class are often drawn into wire, but generally they are in thin plates, so that pieces of an exact size may be cut and laid over the work to be soldered. Before soldering or brazing can be successfully done, the joining surfaces must be made absolutely clean and smooth, and a suitable flux employed in order that the metal or metals will unite to the solder at a low temperature. The flux for steel is, sal-ammoniac 1, borax 10--these ingredients to be powdered together, fused, and pulverized; for iron, borax or sal-ammoniac; for pewter, olive-oil; for tinned iron, chloride of zinc or rosin; for lead and tin, rosin or sweet-oil; for copper and brass, chloride of zinc or sal-ammoniac; for lead-pipe, tallow or rosin; for zinc, chloride of zinc; for spelter-solder, borax.

Owing to the greater affinity of copper for zinc than for tin, some difficulty is usually experienced when zinc is to be soldered with the copper-bit or soldering-iron. This metal seems to remove the tin coating from the copper-bit, causing much trouble sometimes; but this may be obviated by using the soldering fluid as a flux. The latter flux is an admirable one for nearly all other metals, and does not necessitate that degree of cleanness so essential when other fluxes are employed.

Soldering fluid is made by taking two ounces muriatic acid, add zinc till the bubbles cease to rise, then add one half-teaspoonful sal-ammoniac and two ounces water. Iron and steel may be soldered by using this fluid flux without any previous tinning.

Gold is the solder for platinum, with borax for a flux. See GOLD-SOLDER. A good solder for iron is good tough brass, with borax for the flux. See BRASS.

For the hammered-brass solder add a little chloride of potassium to the borax for a flux.

Iron is soldered to steel or either to brass by applying in a molten state tin 3, copper 39 1/2, zinc 7 1/2 parts.

Cold-soldering (without fire) is done by using a mixture composed of bismuth 1/4 ounce, quicksilver 1/4 ounce, block-tin filings 1 ounce, muriatic acid 1 ounce.

Cold-brazing (without fire): Brass-filings 2 ounces, steel-filings 2 ounces, fluoric acid 1/4 ounce. Place the filings in the acid and, when dissolved, apply the solution to the parts to be joined. Fluoric acid should be kept in lead or earthen vessels.

Brass is readily soldered, in some cases, by first using sal-ammoniac as a flux and then placing a piece of tin-foil between the pieces and applying the hot iron until it melts.

German silver is soldered by first applying the soldering fluid as a flux and using pewter solder with the blowpipe.

When arsenic is mixed with solders it should be added at the last, taking care to avoid the fumes.

When brass is employed as an ingredient it should be added after fusing the other metals, to avoid wasting the zinc. The following are the ingredients used for making solders in common use:

Arsenic. Hardening. Gold. Zinc. Tin. Lead. Brass. Bismuth. Copper. Silver. Antimony. Pewter-solder..... 1 1-2 Plumber's solder..... 3 5 1 Plumber's solder..... 1 2 Spelter-solder, for brass..... 1 1 Tinman's solder..... 1 1 Pewterer's soft solder..... 3 4 2 Zinc-solder..... 1 1-2 Glazier's solder..... 3 1 Black solder..... 3 2 2 White solder for raised Britannia-ware..... 8 100 8 Hardening for Britanniaware..... 1 2 Soft solder for Britanniaware..... 8 5 Yellow solder for brass or copper..... 29 1 32 Yellow solder for brass or copper, easily fused..... 55 45 Bismuth-solder..... 1 3 3 Solder for brass, to be hammered..... 17.41 78.26 4 Brass-solder..... 38 3/4 61 1/4 Brass-solder white..... 27.99 14.60 57.41 Solder for steel joints..... 2 1 19 Gold-solder..... 1 3 2 Gold-solder fine..... 12 2 2 Silver-solder, hard..... 1 4 Silver-solder, soft..... 3/4 1 2 Jewellers' solder, hard..... 1/2 3 1/2 16 Jewellers' solder, medium..... 1 4 15 Jewellers' solder, softer..... 1 1/2 4 1/2 14 Hard solder..... 1 2 Spelter-solder for copper or iron..... 12 16