For easily fusing, make an alloy of equal parts of brass and zinc.
For a white hard solder use brass, 12 parts; zinc, 1 part; and tin, 2 parts.
Soldering Fluxes.—For soft soldering, use a solution of chloride of zinc and sal ammoniac. Powdered rosin is also used.
For hard soldering, borax is used most frequently.
A mixture of equal parts of cryolite and barium chloride is very good in soldering bronze or aluminum alloys.
Other hard solders are alloyed as follows: brass, 4 parts; and zinc, 5 parts. Also brass, 7 parts; and zinc, 2 parts.
Steel Tempering-.-Heat the steel red hot and then plunge it into sealing wax.
For tempering small steel springs, they may be plunged into a fish oil which has a small amount of rosin and tallow.
Varnishes.—Black Varnish. Shellac, 5 parts; borax, 2 parts; glycerine, 2 parts; aniline black, 6 parts; water, 45 parts. Dissolve the shellac in hot water and add the other ingredients at a temperature of 200 degrees.