To polish tin, use whiting or Vienna lime, the first being applied with chamois and the second with linen rags. If merely places in relief are to be polished a broad, rounded-off burnisher is applied, and as a polisher, white of egg, ox-gall diluted with water, soap water, or a decoction of soap root, is used. The articles are then washed with water slightly tinged with tartar and dried.
A good polishing water is secured by shaking together 1 lb. of alcohol, 8 8-100 ounces whiting, 1 1/2 drachms spirits of sal-ammoniac.
(1) To polish sheet zinc a good method is found in the following: First scrape and finally polish the zinc with pulverized wood charcoal or Vienna lime. The polished articles are generally dried in heated sawdust and after drying freed from adhering sawdust with a cotton rag or soft leather.
(2) Old zinc can hardly be made to look like new, but may be improved by scouring it with dilute acid and a scratch brush or dust of scouring brick. It may then be rubbed with some finer polishing substance.
(3) Mix 1 part of muriatic acid with 2 parts of water. Apply to the zinc and rub the same with sand until bright. Then dry well and rub with a cloth dipped in oil.
Pulverize and dissolve the following articles in 1 qt. hot water: Blue vitriol, 1 oz.; borax. 1 oz.; prussiate of potash, 1 oz.; charcoal, 1 oz.; salt, 1/2 pt.; then add 1 gal. linseed oil, mix well, bring your iron or steel to the proper heat and cool in the solution.
It is said the manufacturer of the Judson governor paid $100 for this receipt, the object being to case-harden iron, so that it would take a bright polish like steel.
Potassium ferricyanide is made by allowing chlorine to act upon a solution of yellow prussiate of potash. It comes in the form of prismatic and occasionally tubular crystals.
71 9-10 parts Copper,
24 9-10 parts Zinc,
1 2-10 parts Tin,
2 parts Lead.
A powder for silvering metal is made as follows: Nitrate of silver, 10 parts; common salt, 10 parts; cream of tartar, 30 parts; moisten with water and apply.
To make a permanent preservative for iron or steel, it is best to use nothing but linseed oil, thickened with a pigment related to the metal itself, and native oxide or a roasted oxide of iron is the best for the purpose. Boiled linseed oil will form a skin, through which no oxidation can take place.
To preserve polished iron surfaces from rust, melt together 7 parts fat (tallow), and 1 part resin, stirring the same until it cools. Apply in a half liquid state; if too stiff, thin with benzine or petroleum. It preserves the polish, and can easily be removed.