Alum cement. Dissolve good hard soap, by heating in rain water, dilute the thickly fluid mass and add saturated alum solution as long as a precipitate is formed. Collect the gelatinous precipitate of alumina soap thus formed upon a cloth, and, after draining, pour rain water over it ten to twelve times to remove the salts as much as possible. After washing, dry the alumina soap, and rub it to a fine powder.
To prepare cement rub a portion of the powder with sufficient linseed-oil varnish to form a plastic dough, which is used for filling in the joints.
This cement is water-proof, resists high temperatures without being absolutely fire-proof, and, on account of its light color, is well adapted for joining marble plates, etc.
Oil cement for glass. Litharge 30 parts, burnt lime 20, pipe-clay 10, linseed-oil varnish 6.
Oil cement free from lead for steam pipes. Graphite 12 parts, heavy spar 16, slaked lime 6, boiled linseed oil 6.
Oil cements for steam pipes. I. Litharge 25 parts, air-slaked lime 10, quartz sand 10.
Mix the ingredients quickly with the linseed oil and work the mass thoroughly in a hot mortar. Coat the defective places in the pipes with linseed-oil varnish, apply the cement hot and when partially solid, make it still tighter by heating.
II. Boil 60 parts of graphite, 50 of air-slaked lime, 60 of elutriated heavy spar in 35 of linseed oil, stirring constantly. Apply the mixture hot.
Oil cement for marble. Elutriated litharge 10 parts, brick dust 100, linseed oil 20.
Prepare in the same manner as glaziers’ putty. For various colors add zinc white for white, red lead for red, pyrolusite for brown, etc. Previous to applying the cement saturate the surfaces of the stones to be cemented with linseed-oil varnish.