Weed and Metal, Glass, or Stone, to join.—To a strong solution of glue, is added sifted earth, till the mixture has the consistence of varnish. The mass is applied, while still hot, to the surfaces to be united, and the latter are tightly compressed.
b. Non-resinous.—The group of " non-resinous cementing compounds" embraces all those whose composition does not permit them to be included in any of the preceding classes. With the excep tion of purely metallic cements, which have been already described as Solders (see Alloys), this concludes the list of cementing substances :— Architectural.—Strong rice-water size is mixed with paper which has been pulped in boiling water ; whiting is then added, in sufficient quantity to produce the desired consistence.
Beale's.—Chalk, 60 parts; lime, 20 parts ; salt, 20 parts ; Barnsey sand, 10 parts ; iron filings or dust, 5 parts ; blue or red clay, 5 parts ; ground together, and calcined ; patented as fireproof.
Bruyere's.—Clay, 3 parts; slaked lime, 1 part; mixed, and exposed for three hours to full red heat, then ground to powder. Hydraulic.
Building.—A mixture of clay or loam, broken pottery, flints, siliceous sand, or broken bottle glass, and wood ashes ; exposed to considerable heat in a furnace till it partially vitrifies ; then ground to fine powder, sifted, and mixed with one-third its weight of finely powdered quicklime ; afterwards packed closely in barrels, and preserved from air and moisture. For use, it is mixed up with water. Resembles Roman cement.
Caseine.—Instead of dissolving caseine in an alkaline carbonate, Dr. Wagner recommends the use of a cold saturated solution of borax, or an alkaline silicate, for the purpose. The bored° solution of caseine is a clear, viscous liquid, exceeding gum in adhesiveness, and applicable to many uses as a substitute for glue. The chief cement used in the island of Sumatra is made from the curd of buffalo milk, prepared in the following way. The milk is left to stand till all the butter has collected at the top. The latter is then removed, and the thick, sour mass left is termed the curd. This is squeezed into cakes and left to dry, by which it becomes as hard as flint. For
use, some is scraped off, mixed with quicklime, and moistened with milk. It holds exceedingly well, even in a hot, damp climate, and is admirably adapted for mending porcelain vessels.
Chinese.—Bullocks' blood is mixed with one-fifth its weight of quicklime. It will scarcely keep longer than for seven or eight days, when the temperature is elevated. For use, it is thinned by the addition of a little water. It is employed by bookbinders and trunkmakers.
Curd.—(a) Skimmed milk is curdled by the addition of vinegar or rennet, and is then beaten to a paste with powdered quicklime. (b) Skimmed milk, I- pint ; vinegar, piut ; mixed with the whites of flve eggs ; the whole well beaten, and suffioient quicklime added to form a paste. These cements are used for mending glass and earthenware ; they resist water, and a moderate degree of heat.
Earthenware, for. —Grated cheese, 2 parts ; finely powdered quicklime, 1 part ; white of egg, sufficient to form a paste when the whole is beaten up together.
Egg.—Consists of white of egg thickened with finely powdered quicklime. It does not with stand long exposure to moisture, except after subjection to heat. It is employed to mend china, glass, alabaster, marble, earthenware, &c.
Gad's.—Clay, well dried and powdered, 3 parte ; oxide of iron, 1 part ; mixed together, and made into a stiff paste vvith boiled oil. Used for work required to harden under water.
Glass Flux.—Red-lead, 3 parte ; fine white sand, 2 parts ; orystallized boracic acid, 3 parts ; mixed and fused ; levigated, and applied with thin mucilage of gnm tragacanth. The edges to be united must be heated, so as partially to fuse the cement. It is used for mending broken china, &c.
Glass and Porcelain, to join.—Starch, 60 parte ; finely pulverized chalk, 100 parts, are made into a mixture with equal parts of water and spirit, with the addition of 80 parts of Venice tur pentine, taking oare to agitate the mass with a stick, so s,s to ensure its homogeneity.
Glass, Wood and Metal, to join.—(a) Glue, melted with the least possible quantity of water, 4 parts ; Venice turpentine, 1 part. It well resists moisture.