The way to bend tin, brass, or copper tubes is as follows: Make the tube with a lap seam, solder it, and solder up one end. Fill the tube with melted rosin and let it get cold. With a little care it can then be bent nicely in any shape by keeping the seam on the inside of the bend. Tubes have been bent up to 3/4 inch.
Biddery metal is made of:
84 3-10 parts Zinc, 11 4-10 parts Copper,
2 9-10 parts Lead, 1 4-10 parts Tin, or from 93 4-10 parts Zinc,
3 1-10 parts Lead,
3 5-10 parts Copper.
Birmingham Sheet Britannia metal is composed of:
1 5-10 parts Copper, 7 8-10 parts Antimony, 90 6-10 parts Tin.
Birmingham Cast Britannia metal is composed of:
9-100 parts Copper, 9 2-10 parts Antimony, 90 71-100 parts Tin.
Bismuth nitrate is obtained by the dissolution of bismuth in nitric acid.
A good black finish to copper it given by putting same in a pickle consisting of 4 parts of concentrated hydro-chloric acid, 1 part sulphuric acid (of 66 degrees Be), and 2 parts arsenic acid and 24 of water. This pickle is to be heated before using.
The simplest method to blacken iron is to heat it with oil, especially linseed. The objects are first rubbed or painted with oil and then heated to such an extent that the oil is burned off. The surface produced in this manner is coal black, and gives the objects a black coloring, which will withstand the highest temperature. After the application is thoroughly dried, the objects can be rubbed with benzine or a solution of soda. In order to produce a black asphalte lac for iron, melt 8 pounds of asphalte in an iron kettle, gradually adding 12 pints of cooked linseed oil, 1 pound of litharge, and 1/2 pound of sulphate of zinc. The whole mixture should be allowed to boil three hours. Finally, 1 1/2 pounds black umber is to be added, and the mixture carefully boiled for two hours longer. It is advisable previous to using this mixture to thin it by the addition of oil of turpentine.
Iron black is a finely divided antimony powder, which is precipitated from a solution of antimony by zinc.
Some good receipts for harness blacking are made as follows:
1. Treacle, 1/2 pound; lampblack, 1 ounce; yeast, a spoonful; sugar candy, olive oil, gum tragacanth and isinglass each 1 ounce; and a cow's gall. Mix with 2 pints of stale beer and let it stand before the fire one hour.
2. Treacle, 8 parts; lampblack, 1 part; sweet oil, gum arabic, 1; isinglass, 1; water, 32. Apply heat to the whole. When cold add 1 ounce of spirits of wine and apply with a sponge. If it should get hard, place the bottle in warm water a short time.
For blacking sheet zinc for the purpose of drawing lines, so that the blacking will not rub off, also answers for cast-iron, wrought-iron and steel. To 4 ounces of clear water add 1 ounce of powdered sulphate of copper, then 1/2 teaspoonful of nitric acid. Before applying this solution, be sure and brighten the surface which is to be coated. When using, dampen a clean part of waste, passing it over the work. When the surface is large use different parts of the dampened waste, so that the surface will have the same color. Generally the waste turns black after being drawn across the work, and also produces black streaks on the surface coats. This applies only to cast-iron, wrought-iron and steel. These metals when coated have the appearance of copper; but with zinc the surface is black. Rub the surface dry, after applying with clean waste.