Another receipt is as follows:
Mix 2 ozs. of sal ammoniac, 1 oz. of sublimated sulphur and 1 lb. of cast-iron filings or fine turnings in a mortar, and keep the powder dry. When it is to be used, mix it with 20 times its weight of clean iron turnings or filings and grind the whole in a mortar; then wet it with water until it becomes of convenient consistency, when it is to be applied to the joint. After a time it becomes as hard and strong as the metal.
Steam boiler cement. Mix 10 parts of finely-powdered litharge with 1 part of fine sand and 1 part of air-slaked lime. The mixture may be kept for any length of time without deterioration. For use a portion of it is made into a paste with linseed oil or, better, boiled linseed oil. In this state it must be applied quickly, as it soon becomes hard.
Cement for rubber. Powdered shellac is softened in 10 times its weight of strong water of ammonia, whereby a transparent mass is obtained, which becomes fluid after keeping some little time without the use of hot water. In three to four weeks the mixture is perfectly liquid, and when applied it will be found to soften the rubber. As soon as the ammonia evaporates it hardens again, and thus becomes impervious both to gases and to liquids. For cementing sheet rubber, or rubber material in any shape, to metal, glass, and other smooth surfaces, this cement is highly recommended.
Cement for tires. 1. Isinglass 1 oz., gutta-percha 1 oz., rubber 2 ozs., carbon disulphide 8 fluid ozs. Mix and dissolve.
2. Shellac 4 ozs., gutta-percha 4 ozs., red lead and sulphur, each ½ oz. Melt the shellac and gutta-percha, and add with constant stirring the red lead and sulphur, melted. Use while hot.
3. Crude rubber 1 oz., carbon disulphide 8 ozs. Macerate 24 hours, and then add a solution of:
Rosin 2 ozs., beeswax ½ oz., carbon disulphide 8 ozs.
4. Rubber 20 parts, rosin 10, Venetian red 10, tallow 5. Melt the rubber over a fire, then add the rosin and the tallow and finally the Venetian red.
Cement for steam pipes, etc. A cement of specially valuable properties for steam pipes, in filling up small leaks, such as a blow-hole in a casting, without the necessity of removing the injured piece, is composed of 5 lbs. Paris white and 5 lbs. yellow ochre, 10 lbs. litharge, 5 lbs. red lead and 4 lbs. black oxide of manganese. Mix the materials thoroughly and make into a paste with a small quantity of asbestos and boiled linseed oil. The composition, as thus prepared, will harden in from 2 to 5 hours, and has the advantage of not being subject to expansion and contraction to such an extent as to cause a leakage afterwards, and its efficiency in places difficult of access is of special importance.