Brass is composed of variable proportions of zinc and copper, according to the use for which it is required. In general, about 9 parts of zinc are added to 16 of cop per when melted. The best brass is not made by the direct combination of the two fluid metals, but by the process called cementation (See CEMENTATION). The vapour of the zinc ore by this mode combines more intimately with the copper.
Manheim Gold.—Three parts copper, 1 part zinc, and a small quantity of tin If these metals are pure, and are meltal in a covered crucible containing char coal, the alloy bears so close a resemblance to gold as to deceive very skilful persons.
Tombac, or White Copper, is formed of variable proportions of copper, arsenic, and tin.
Pinchbeck.—Five oz. pure copper, and 1 oz. zinc. The copper must be first melted before the zinc is added.
Prince's Metal is made of from 2 to 3 parts of copper, and 1 of zinc; or of common brass, with an extra portion of zinc.
Bell MetaL—Six to 10 parts copper, and 2 parts zinc. For small bells, a little zinc is added, and sometimes silver.
Tutania, or Britannia Metal.—Four oz. plate brass, and 4 oz. tin; when fiused, add 4 oz. bismuth, and 4 oz. antimony. This composition is added at discretion to melted tin.
German Tutania.—Two arms. copper, 1 oz. antimony, and 12 oz. tin.
Spanish Tutania.—Eight oz. scrap iron, or steel, 1 lb. antimony, and 3 oz. nitre. The iron or steel must be heated to whiteness, and the antimony and nitre added in small portions. Two oz. of this compound are sufficient to harden 1 lb. of tin.
Queen's Metal.—Four and a half lbs. tin, lb. bismuth, i lb. antimony, and lb. lead. Or, 100 lbs. tin, 8 lbs. antimony, 1 lb. bismuth, and 4 lbs. copper. This alloy is used for making tea-pots, and other vessels, which imitate silver.
Red Tombac.—Five and a half lbs. of copper, and lb. zinc. The copper must be fused in a crucible before the zinc is added. This alloy is of a red colour, and possesses greater durability than copper.
White Metal.—Ten oz. lead, 6 oz. bismuth, and 4 drum. antimony. Or, 2 lbs. antimony, 8 oz. brass, and 10 oz. tin.
Gun Metal.—One hundred and twelve lbs. Bristol brass, 14 lbs. zinc, and 7 lbs. block tin. Or, 911m. copper, and 1 lb. tin. Lead was formerly used in this alloy to facilitate the casting, but at the battle of Prague it was found that some of the pieces of ordnance formed of this metal were actually melted by the frequency of firing.
Blanched Copper.—Eight oz. copper, and oz. neutral arsenical salt, fused together under a flux of calcined borax and pounded glass, to which charcoal powder is added.
Specula Metal.—Seven lbs. copper, 3 lbs. zinc, and 4 lbs. tin. These metals form an alloy of a light yellow colour, possessing much lustre.
Metal for Flute Key Valves.—Four oz. lead, and 2oz. antimony.
Printing Types.—Ten lbs. lead, and 2 oz. antimony. The antimony is added while the lead is in a state of fusion. The antimony gives hardness to the lead, and prevents its contraction when cooling. Some manufacturers employ different proportions of these metals, and some add copper or brass.
Small Type Metal.—Nine lbs. lead, 211m. antimony, and 1 lb. bismuth. The antimony and bismuth are added when the lead is melted. This alloy expands in cooling ; the mould is, therefore, entirely filled when the Metal is cold, and no blemish is found in the letters. Stereotype plates are formed of this alloy. Some manufacturers employ tin instead of bismuth.
Common Pewter.- –Seven lbs. tin, 1 lb. lead, 6 oz. copper, and 2 oz. zinc. The copper must be first melted before the other metals are added.
Best Pewter.—One hundred parts tin, and 17 parts antimony.
Hard Pewter.— Twelve lbs. tin, 1 lb. antimony, and 4 oz. copper. Common Solder —Two lbs. lead, and 1 lb. tin.
Soft Solder.—Two lbs. tin, and 1 lb. lead.
Solder for Steel Joints.—Nineteen dwts. fine silver, 1 dwt. copper, and 2 dwts. brass.
Silver Solder for Jewellers.—Nineteen dwts. fine silver, 1 dwt. copper, and 10 dwts. brass.
Silver Solder for Plating.—Ten dwts. brass, and 1 oz. pure silver.
Gold Solder.—Twelve dwts. pure gold, 2 dwts. pure silver, and 4 dwts.-copper.
Bronze.—Seven lbs. copper, 3 lbs. zinc, and 2 lbs. tin. The copper must be melted before the other metals are added.
Mock Platinum.—Eight oz. brass, and 5 oz. zinc.
Alloy of Platinum with Gokl.—Fifteen parts pure gold, and 1 part platinum. The gold must be melted before the platinum is added. This alloy is whiter than gold. Platinum has the singular property of depriving gold of its peculiar colour; if ten parts of gold are combined with only one of platinum, the alloy will appear of the colour of platinum. There is another remarkable property attending this alloy of gold and platinum, that it is soluble in nitric acid, which does not act upon either of the metals in a separate state.