Inferior as this kind of plating would seem, it will wear a long time.
To Clean Silver.—Wash with a little spirits of ammonia reduced in strength by twice its bulk of pure water, then rub dry and bright with soft leather. No kind of polishing powder will be necessary. Some workmen clean silver by first washing it over with diluted muriatic acid, then immediately covering the surface with dry prepared chalk, then brushing off and rubbing clean with a bit of chamois skin. It acts very well, but care must be had to get the acid thoroughly cleaned off else it will have a tendency to soon tarnish the silver.
To Work Copper.—This metal is almost as malleable as silver, and works very well under the hammer in a cold state. Heat adds nothing to its malleability, though, as in the case of silver, exposure to a low degree of heat, followed by gradual cooling, softens it somewhat when it has been rendered hard and brittle by long hammering. It polishes very well, but does not long retain its polish and brilliancy on account of its disposition to oxidize. Heating increases its oxidation; repeatedly heating and cooling would soon wear it entirely away.
To Work Brass.—This material is a combination of copper and zinc, and since zinc is not so malleable as copper, it renders the brass less malleable. Nevertheless it forges out pretty well under the hammer, in a cold state, the only condition in which it can be so worked. Hammering increases its hardness with great rapidity, soon converting it into a very fair spring metal. Brass springs are quite common—they are all made by repeatedly hammering or rolling the metal while cold. As in the case of both silver and copper, heating and gradual cooling removes this hardness. This is the plan for softening usually recommended in books on working metals, but no advantage will be found to arise from the gradual cooling in the case of either silver, copper or brass. The custom is to heat the metal to the lowest degree that would show redness and then plunge it directly into cold water.
To Cast Brass.—The gunsmith may occasionally find it necessary to cast something in brass. This he can do without trouble, as brass melts quite easily. The mould should have vents at or near the top to admit the free escape of air as the molten metal runs in to take its place; and it is always best, if possible, to arrange so that the metal will enter the mould near the bottom and rise up in the filling. Without such an arrangement there is danger of air bubbles remaining under the metal and spoiling the casting. The metal should be heated only to a degree high enough to admit of flowing freely and no higher.
To Brass Iron.—Clean and polish the iron thoroughly, being extremely careful not to touch its surface with the fingers at the finishing; then plunge it into molten brass. Take out immediately; a thin coating of brass will be found covering the iron, which may be polished or burnished, giving the article the appearance of solid brass.
To Clean Brass.—To half a pint of soft water add one tablespoonful of oxalic acid. Wash the article with this, then cover with prepared chalk, brush dry and polish with chamois skin, as in cleaning silver. The solution may be bottled and kept on hand for use as wanted.
To Solder Brass.—The processes in soft soldering are the same for all metals, full instructions for which may be found in [Chapter XXXIV]. Hard soldering (see also Chapter XXXIV) is something different, and in the case of brass it is somewhat different on account of the low degree of temperature at which the metal melts. The solder most commonly used is composed of two parts of common brass and one part of zinc, melted together. Reduce your solder to fine bits by cutting or filing, and then mix with sal-ammoniac and borax, the two latter having been pulverized together in equal parts and moistened with water to form a kind of paste. Carefully clean the pieces to be joined, lay them together, place the soldering compound along the upper edge of the joint, which must be held vertically, and then heat gradually over a charcoal fire until the solder is seen to run down between the pieces. The instant the solder is seen to run remove the work from the fire, tap the work gently with a small hammer to jar the solder into all interstices, and, if the work be so that it can be done, scrape off the superfluous solder and burnt borax with an old file.