(2) Copper, 14 parts; zinc, 6 parts; tin, 4 parts.
A good receipt for bronzing gun barrels is: Aqua fortis and sweet spirits of nitre each half an ounce; sulphate of copper, 2 ounces; water, 30 ounces; tincture of muriate of iron, 1 ounce. Mix and apply.
Articles of iron or brass may be bronzed by dipping them into melted sulphur mixed with lampblack. The surface, after being drained off. will take a beautiful polish, and presents the appearance of oxidized bronze.
Copper, 95 parts; tin, 4 parts. Melt together.
A fine bronze for small castings is composed of 94 12-100 parts of copper and 5 88-100 parts tin.
An admirable bronze liquid is made by the dissolution of 1/2 ounce of alum, 1/4 ounce of arsenic and 1 ounce of sal-ammoniac in 1 pint of strong vinegar.
Copper, 27 1/2 parts; zinc, 12 parts; tin, 8 parts. Melt together.
The composition of ormolu bronze is 58 3-10 parts copper, 25 3-10 parts zinc and 16 7-10 parts tin.
A bronze patina on tin is obtained by brushing the article with a solution of 1 3/4 ounces sulphate of copper, 1 3/4 ounces ferrous sulphate in 1 quart of water, then wetting the dried object with a solution of 3 1/2 ounces of verdigris in 10 1/2 ounces of vinegar. After drying, the object is to be polished with a soft brush rubbed upon wax and some iron rust. This coating should be protected by lacquer.
The bronzes that Pizarro found in Peru, and which excited the admiration of Europe when introduced, were composed of 95 parts copper, 4 5-10 parts tin, 3-10 parts iron and 2-10 parts lead.
This substance, which is largely used in place of bronze and gun metal compositions, for bearings, wire, rope, gearing, etc., is a copper-tin alloy, fluxed by the introduction of a quantity of phosphor. The addition of this latter is generally made in the form of phosphide and tin or phosphide and copper.
The bronze for use in statuary must become thinly fluid. It must also acquire a beautiful green color, technically known as patina, on brief exposure to the atmosphere. As practically the sole use of this bronze is for artistic purposes, the color is very important. The bronze at present most in vogue for statuary consists of 86 6-10 per cent. of copper, 6 6-10 per cent. tin, 3 3-10 per cent. lead and 3 3-10 per cent. zinc.