Cement for porcelain. Caseine dissolves readily in solution of water-glass, and forms then one of the best cements for porcelain known. To prepare it, fill a bottle one-quarter full with fresh caseine, and after filling the bottle with solution of water-glass, effect the solution of the caseine by frequent shaking.
Cement for meerschaum. Dissolve caseine in water-glass, and after stirring quickly finely-pulverized calcined magnesia into the mass, use it at once, as it solidifies very soon. By adding, besides magnesia, genuine meerschaum finely pulverized, a mass closely resembling meerschaum is obtained, which can be used for manufacturing imitation meerschaum.
Cement for wood, etc. Rub 10 parts of caseine and 5 of borax to a thick, milky mass, and use it like glue. This cement can be advantageously used for pasting labels upon wine bottles, as it neither moulds nor becomes detached in the cellar.
Another formula is as follows: Dissolve borax by boiling in water, and pour the solution over fresh caseine. The result will be a clear, thick mass of extraordinary power of adhesion, which can be kept for any length of time without suffering decomposition.
Applied to leather, paper, linen or cotton goods, it forms a coat of beautiful lustre, and for this reason is much used in the manufacture of fancy articles of paper and leather.
Cement for porcelain. Dissolve 10 parts of caseine in 60 of water-glass solution. Apply the cement quickly and dry the cemented articles in the air.
WATER-GLASS AND WATER-GLASS CEMENTS.
Water-glass. Water-glass (silicate of soda or soluble glass) is found in commerce as a thickly-fluid, tenacious mass. It is generally prepared by fusing 15 parts of quartz sand with 8 of carbonate of soda and 1 of charcoal. The silicic acid combining with the soda disengages the carbonic acid, the expulsion of which is facilitated by the presence of charcoal, which converts it into carbonic oxide. It dissolves readily in water. The solution has a strongly alkaline taste, and possesses the property of being gradually converted, on exposure to the air, to a gelatinous mass which finally solidifies. For this reason water-glass should be kept in bottles hermetically closed with corks. Glass stoppers are of no use, as they are so firmly cemented to the bottle that on attempting to open the latter the neck breaks off.
By combining water-glass with cement or burned lime the resulting mass solidifies quite rapidly to a mass as hard as stone, and generally capable of resisting chemical action.
Water-glass by itself is only fit for cementing glass to glass, but combined with other substances it furnishes very durable and solid cements.