The color of zinc may be changed by immersing the zinc in a mixture of 100 parts sulphuric acid, 100 parts nitric acid, and common salt 1 per cent. After remaining a little while in the mixture it acquires a dead lustre; this will become a bright one if the object is plunged in several times, and rinsed as often, in the same compound.
For a good paint for tin pots use the following: Make a thick varnish of shellac dissolved in naphtha or methylated spirit. Two or three coats should be applied.
A good paint for a tin roof is made from common Spanish brown, Venetian red, or yellow ochre, mixed with either pure raw linseed oil, or equal parts linseed and fish oil; the only partial drying of the latter causing a degree of elasticity in the coat of paint which prevents its cracking during the expansion and contraction of the metal.
To make paint adhere to sheet zinc: Made a mordant as follows: One part chloride of copper, 1 of nitrate of copper, and 1 of sal-ammoniac, dissolved in 64 parts of water, to which add one part of commercial hydrochloric acid. The sheets of zinc should be brushed over with this liquid, when they will assume a dark color. After they are dry they can be painted, and the paint will not be affected by changes of the weather.
For making gray oil-color luminous paint and a yellowish-brown oil-color luminous paint, take pure linseed oil, cold-press it and thicken by heat.
Then for the gray paint: Take 45 parts of oil, mix with 6 parts prepared barium sulphate, 6 parts prepared calcium carbonate, .05 part ultramarine blue, 6.5 parts gray zinc sulphide.
For the yellowish-brown oil-color luminous paint, take 48 parts of the pure linseed oil, 10 parts precipitated barium sulphate, 8 parts auripigment, and 34 parts luminous calcium sulphide.
Fireproof paper may be made from a pulp consisting of 1 part of vegetable fibre, 2 parts of asbestos, 1-10 part borax, 1-5 part of alum. The ink is made from 85 parts of graphite, .8 part of copal varnish, 7.5 parts of copperas, 30 parts of tincture of nutgalls, and a sufficient quantity of indigo carmine.
Rotten stone, 4 1/2 pounds; oxalic acid (dissolved in water), 2 ounces; soft soap, 8 ounces; sweet oil, 8 ounces; boiling water, 1 pound; spirits of turpentine, 1 ounce. Mix.
Well-prepared bill-stickers' paste is as good as anything we know of for pasting asbestos to tin hot air or furnace pipes, and will not scale off when the pipes are heated.
Here is a receipt for fastening labels on tin which makes a strong mucilage: Soften good glue (fish glue is most tenacious) in water; then boil it with strong-vinegar and thicken the liquid, during boiling, with fine wheat flour, so that a paste results; or starch paste, with which a little Venice turpentine has been incorporated while it was warm.
A "paste" metal polish for cleaning and polishing brass is thus made: Oxalic acid, 1 part; iron peroxide, 15 parts; powdered rotten stone, 20 parts; palm oil, 60 parts; petroleum, 4 parts. See that solids are thoroughly pulverized and sifted, then add and thoroughly incorporate oil and petrolatum.