Cements for uniting pieces of alabaster, marble, Derbyshire spar, and other kinds of white stone, are in frequent demand. The following recipes give satisfactory results. Those containing resin must be applied hot, and the pieces to be joined must also be heated up to the melting-point of resin. (1) Plaster-of-Paris made to a cream with water. Sets in a few minutes, but it does not become perfectly hard for several days, or until it is thoroughly dry. (2) Yellow resin, 2 parts; melt and stir in 1 part of plaster-of-Paris, which has been thoroughly dried and heated. (3) Yellow resin, beeswax and plaster-of-Paris, equal parts. (4) Resin, 8 parts; wax, 1; melt and stir in 4 of plaster-of-Paris.
This lute is composed of 2 parts wood ashes, 3 lime, 1 sand, mixed, passed through a sieve, moistened with water and oil, and beaten up with a wooden mallet till the compound has acquired the right consistence.
(1) Ground almond cake, from which the oil has been expressed, is mixed up with an equal weight of whiting, and made into a stiff paste with water. It soon becomes very hard and tough. It is much employed for luting stills, retorts, etc, when the heat does not exceed about 320° F. (160° C.); it is capable of resisting the fumes of volatile oils, spirits, weak acids, etc, for some time, (2) Ground almond cake as (1), or linseed cake, is added to starch paste and gum-water.
Amber - (1) 2 surfaces of amber may be united by smearing them with boiled linseed oil, pressing them strongly together, and heating them over a clear charcoal fire. To keep the parts in firm contact, it may be well to tie them with the soft iron wire, known as binding wire. (2) A solution of hard copal in pure ether, of the consistency of castor oil, is suggested by Ph. Rust for cementing amber. The Carefully-cleaned surfaces of fracture, coated with the solution, should be pressed together, and retained in contact by means of a string wound around the object, or in some other suitable way. The operation should be performed as rapidly as possible, since the evaporation of the ether impairs the adhesiveness of the cement; so that all arrangements for compressing the object should be made before laying on the cement. A few days are required for the complete hardening of it. In repairing tubes, as for pipes, any of the solution happening to pass into the interior should be carefully removed at once with a slender feather. (3) The Canadian Pharmaceutical Journalstates that amber may be cemented by moistening the surfaces with solution of potash, and pressing them together.
This term has been applied to various waterproof cements which have been used for joining the sides, ends, etc, of tanks for holding water for various purposes. The following are some of the best. (1) Take of finely powdered litharge, fine, white, dry sand, and plaster-of-Paris, each 3 parts, by measure; finely pulverized resin, 1 part. Mix thoroughly and make into a paste with boiled linseed oil to which dryer has been added. Beat the mixture well, and let it stand 4 or 5 hours before using it. After it has stood for 15 hours, however, it loses its strength. When well made, of good materials, this cement will unite glass and iron so firmly that the glass will often split in its own substance, rather than part from the cement. Glass cemented into its frame with this cement is good for either salt or fresh water. It has been used at the Zoological Gardens, London, with great success. It might be useful for stopping leaks in roofs and other situations. (2) This highly recommended cement is made by melting together, in an iron pan, 2 parts common pitch and 1 part guttapercha, and stirring them well together until thoroughly incorporated, and then pouring the liquid into cold water.
When cold, it is black, solid, and elastic; but it softens with heat, and may be used as a soft paste, or in the liquid state, as is most suitable. It does not harden and crack, and answers an excellent purpose in cementing metal, glass, porcelain, ivory, etc. It may be used instead of putty for glazing windows. (3) Red lead, 3 parts; litharge, 1 part; made into a paste or putty with raw linseed oil. (4) A cement which gradually hardens to a strong consistence may be made by mixing 20 parts of clean river sand, 2 of litharge, and 1 of quicklime, into a thin putty with linseed oil. When this cement is applied to mend broken pieces of stone, as steps* of stairs, it acquires, after some time, a stony hardness, and unites the parts with great firmness. (5) It is said that a cement of great adhesiveness may be made by mixing 6 parts of powdered graphite with 3 of slaked lime, 8 of sulphate of baryta, and 7 of linseed oil varnish. The mixture must be stirred to uniform consistency. (6) 1/2 lb. best white lead, ground in oil; 1/2 lb. red lead, dry; 1/2 lb. litharge, dry; the two last kneaded into the first. You have now 1 1/2 lb. of the best putty for resisting water. It will soon become hard and continue so.
The glass should be bedded in it, and when neatly finished, put away for a fortnight; then varnish with shellac, dissolved in methylated spirits - say, 1 1/2 oz. to half a gill - put into a bottle and shaken, will be ready in an hour. It may be coloured, if need be, with a little vermilion. One coat, wherever there is any putty or metal exposed, will be sufficient, and will dry in a few minutes. Your tank will never leak after this if the frame and glass are strong. (7) Mix boiled linseed oil, litharge, red and white lead together, using white lead in the largest proportion, spread on flannel, and place on the joints. (8) A solution, of 8 oz. glue to 1 oz. of Venice turpentine; boil together, agitating all the time, until the mixture becomes as complete as possible; the joints to be cemented to be kept together for 48 hours if required. (9) Take 1/2 gill of gold size, 2 gills of red lead, 1} gill of litharge, and sufficient silver sand to make it a thick paste for use. This mixture sets in about two days. (10) Stockholm tar and red lead dries quickly and hard, after having been mixed to the consistency of butter. Good for almost anything except where great heat is used. (11) Zinc white 2 parts, copal varnish 1 part. (12) Common resin 8 parts, calcined plaster 1 part. Melt and incorporate.