By means of the caulking iron, and the piece of board or plate, stuff the moist material into the joint to a depth of 1 in. or so from the bottom, all round; now caulk it down with the iron and hammer until it sounds perfectly solid, as though it struck against solid iron. Repeat the process of filling, then the caulking, and so on, until the joint is filled to the surface. The joint should rest for at least ten hours before being put under pressure. (See also ii. 89.)
Dissolve 1 part of isinglass and 2 of white glue in 30 of water, strain and evaporate to 6 parts. Add 1/30 part of gum mastic, dissolved in 1/2 a part of alcohol, add 1 part of zinc white. When required for use, warm and shake up. (See also ii. 90.)
Shellac is the only cement used by jewellers for jet articles. The broken edges should be made warm before applying the cement. Should the joint be in sight, by smoking the shellac before applying it, it will be rendered the same colour as the jet itself.
A good cement for splicing leather for straps is gutta-percha dissolved in bisulphide of carbon, until it is of the thickness of treacle; the parts to be cemented must first be well thinned down, then pour a small quantity of the cement on both ends, spreading it well so as to fill the pores of the leather, warm the parts over a fire for about half a minute, apply them quickly together, and hammer well. The bottle containing the cement should be tightly corked and kept in a cool place. (See also ii. 92.)
Boil a piece of Gloucester cheese three times in water, each time allowing the water to evaporate. Take the paste thus left and thoroughly incorporate with dry quicklime. It will mend glass, wood, china, etc, very effectually.
Take plaster of Paris, and soak it in a saturated solution of alum, then bake in an oven, the same as gypsum is baked to make plaster of Paris; after which grind the mixture to powder. It is then used as wanted, being mixed up with water like plaster, and applied. It sets into a very hard composition capable of taking a very high polish, and may be mixed with various colouring minerals to produce a cement of any colour capable of imitating marble. This cement is also used for attaching glass to metal. (See also ii. 93.)
(a) Take some garlic and crush it, in order to form a kind of dough, rub over the broken pieces of meerschaum with it and reunite them by drawing very closely; bind them with iron wire according to the strength of the pieces, and finally make them boil during half an hour in a sufficient quantity of milk.
(6) Melt rosin 180 parts, and stir in burnt umber, 30; calcined plaster, 15; and boiled oil, 8 parts.
(c) Dissolve glue in boiling water to the consistence of cabinet-maker's glue, then stir in sufficient wood ashes to produce a varnish-like mixture. While hot, the surfaces to be united must be covered with this compound and pressed together. (See also it. 95.)
The best cement for pasting parchment paper is casein glue. It is much better than so-called chrome glue, because the latter produces yellow or brownish spots where it has been employed. Casein glue is a solution of casein, which appears as whey or drop when milk is allowed to curdle. The glue is dissolved in a saturate 1 solution of borax. When dried in the form of transparent gelatine, it appears as greyish white and somewhat brittle matter, which can be easily dissolved in water, and possesses great adhesiveness. When employed for passing parchment paper, a thin paste is prepared, used in the customary manner, and the jointed places are afterwards exposed for a little while to a jet of steam.
Place half a quartern of flour in a saucepan, put as much cold water on it as will cover it, and stir it well up, so as to break all the lumps while in a state of dough. Then pour on about 2 quarts of cold water and 1 oz. of powdered alum. Stir well and boil till it becomes thick. (See also ii. 98.)
Fine wheat starch, 4 dr., beat into a paste with cold water; 1 oz. of best Russian glue dissolved in a pint of boiling water; while boiling, pour on the starch; put the whole into a saucepan, and boil till as thick as treacle. When required for use a small quantity is to be melted in a little warm water.
Cut virgin or native rubber with a wet knife into the thin-nest possible slices, and with shears divide these into threads as fine as fine yarn. Put a small quantity of the shreds (say 1/10th or less of the capacity of the bottle) into a wide-mouthed bottle, and fill it three-quarters full with benzine of good quality, perfectly free from oil. The rubber will swell up almost immediately, and in a few days; especially if often shaken, assume the consistence of honey. If it incline to remain in undissolved masses, more benzine must be added; but if too thin and watery, it needs more rubber. A piece of solid rubber the size of a walnut will make a pint of the cement.
This cement dries in a few minutes, and by using three coats in the usual manner, will unite leather straps, patches, rubber soles, backs of books, etc, with exceeding firmness. (See also v. 17.)
Clean river sand, 201b.; litharge, 2 lb.; quicklime, 1 lb.; linseed oil, sufficient to form a thin paste. This cement is applied to mend broken pieces of stone, and after a time it becomes exceeding hard* and strong. A simitar composition has been used to coat brick walls, under the name of mastic. (See also ii. 108, v. 18.)
(a) Take Burgundy pitch, 2 lb.; rosin, 2 lb.; yellow wax, 2 oz.; dried whiting, 2 lb.: melt and mix.
(6) Black rosin, 1/2 lb.; yellow wax, 1 oz.; melt together, and pour into a tin canister. When wanted for use, chip out as much as will cover the chuck to 1/16 th of an inch, spread it over the surface in small pieces, mixing it with an eighth of its bulk of guttapercha in thin slices; then heat an iron to p. dull red heat, and hold it over the chuck till the mixture and gutta are melted and liquid; cool the iron a little and with it stir the cement until it is homogeneous; chuck the work, lay on a weight to enforce contact, leave it at rest for half ah hour, when it will be ready for the lathe.
(c) Four parts rosin melted with 1 part pitch; while these are boiling add brick-dust until by dropping a little upon a cold stone you think it hard enough. (See also ii. 109.)
(a) Make a paste of slaked lime, 1 part; rye meal, 2 parts; with a sufficient quantity of linseed oil.
(b).Dissolve 1 fart of glue in 16 parts of water, and when almost cool stir in saw-dust and prepared chalk a sufficient quantity.
Take as small a quantity of the cement as possible, and bring the cement itself into intimate contact with the surfaces to be united. If glue is employed, the surface should be male so warm that the melted glue is not chilled before it has time to effect a thorough adhesion. Cements that are used in a fused state, as rosin or shellac, will not adhere unless the parts to be joined are heated to the fusing point of the cement. Sealing-wax, or ordinary electrical cement, is a good agent for uniting metal to glass or stone, provided the masses to be united are made so hot as to fuse the cement, but if the cement is applied to them while they are cold it will not stick at all. This fact is well known to the itinerant vendors of cement for uniting earthenware. By heating two pieces of china or earthenware so that they will fuse shellac, they are able to smear them with a little of this gum, and join the pieces" so that they will rather break at any other part than along the line of union. But although people constantly see the operation performed, and buy liberally of the cement, it will be found in nine cases out of ten that the cement proves worthless in the hands of the purchasers, simply because they do not know how to use it.
They are afraid to heat a delicate glass or porcelain vessel to a sufficient degree, or they are apt to use too much of the material, and the result is a failure.