( Originally Published 1906 )
THE following working formule are all practical, having been tested by the author. A number represent standard formule which have been hitherto published in a number of works on glue, having been known for years to investigators. Others, again, are the result of the author's personal experience. Carefully carried out, they will all yield satisfactory results.
A. Glues rendered water-proof by mixture with other substances.
1. Glues may be rendered practically water-proof by the addition of a small quantity (1 per cent) of ammonium or potassium bichromate to their solutions. The glue becomes water-proof only upon exposure to the influence of the sun's rays.
2. The addition of a limited quantity of formaldehyde to the aqueous solution of glue will aid it in resisting the action of water after it has dried for a time.
3. Ten parts of glue are soaked in an equal volume of water and the glue removed before it has lost its primitive form. The swollen glue is then dissolved in about 10 parts of linseed oil with the aid of heat until until a jelly is formed. This mixture is an effective cement for joining a number of materials and is practically water-proof.
4. Twelve parts of glue are dissolved in 15 of water. Two parts of bleached rosin are added and the heating continued until the rosin and glue are uniformly incorporated. Four parts of turpentine are now cautiously added and the whole stirred until uniform.
B. Water-proof Substitutes for Glue.
1. Dammar and other cheap varnishes are sufficiently sticky to fulfil the adhesive requirement of glue, and possess the advantage over the former in that they are absolutely water-proof. These cannot be used as water-proof coatings.
2. Shellac may be dissolved in wood alcohol to the consistency of a heavy solution of glue and may be used as a water-proof glue in the lighter work to which glue is applicable.
3. Marine glues are water-proof cements containing no glue whatsoever. They are admirably adapted to the calking of vessels, whence, in all probability, their name. Jeffrey's marine glue is perpared incorporating shellac with, a solution of 1 part of india-rubber in benzine. Others are combinations of solutions of rubber in refined petroleum (1 part rubber, 12 parts solvent) with 20 parts of asphaltum. The asphaltum is melted separately in an iron boiler and the rubber solution added in a thin stream, the whole stirred until uniform.
Mending Cements. — These comprise numberless preparations of greater or less value. Some few give satisfactory results and are here described.
A. Cements for Iron and Other Metals.
1. Marine glue, above described, may be used to advantage in cementing metal to metal.
2. A cement for pipe-joints is prepared by mixing red lead with linseed oil to a thick paste.
3. Diamond cement for metal. Into 40 parts of linseed oil there are slowly stirred the following, in order named : Litharge, 30 parts; slaked lime, 10 parts; whiting, 20 parts; and graphite, 100 parts. The cement is to be applied hot to the slightly roughened surface of the metal.
4. An oil cement for steam-pipes, which is free from lead, is prepared by mixing intimately 1 part of graphite, 3 of heavy spar, 1 of slaked lime, and 1 of linseed oil. The mineral ingredients are first to be mixed well and the mixture incorporated with the linseed oil.
5. Casein, 8 parts; slaked lime, 10 parts; quartz sand, 10 parts. In place of the sand, finely divided silex (silica) such as is employed to "fill" scouring soaps, may be employed to advantage.
6. For uniting metals, a strong cement is made by the addition of good quality whiting (Extra Gilder's will answer) into a solution of silicate of soda (water glass) of 40°. Be. Sufficient whiting is added to form a plastic mass. This cement has the advantage in that it may be colored by the addition of such substances as antimony sulphide for black, cupric carbonate for light green, chromium oxide for dark green, etc.
B. Cements for Porcelain and Crockery.
1. White pitch, 9 parts; sulphur, 14 parts; bleached shellac, 2 parts; gum mastic, 4 parts; gum elemi, 4 parts; finely powdered and sifted glass, 14 parts. All ingredients, excepting, of course, the glass, are to be melted together and the glass stirred into the melted mass.
2. Gutta-percha, 1 part, and shellac, 1 part, are cautiously melted together by the aid of indirect heat, preferably by placing the vessel containing them over the water-bath. The melted ingredients should be well mixed and applied hot, having previously warmed the edges of the pieces to be cemented.
3. Casein, 10 parts, is dissolved in silicate of soda, 100 parts, by constant shaking of the mixture. If applied rapidly, this is a most effective cement for mending crockery and glassware that is to be heated.
C. Cements for Glass.
1. For mending broken glassware, provided this does not have to be heated, there is no better cement than water-glass itself. This must be carefully applied, special care being taken not to smear the surface of the glass as, once dried, the cement will never come off. It is best used in fairly heavy solution and applied by means of a fine camel's-hair brush which should at once be cleaned by dipping it in boiling water. The fractured edges of glass should be just slightly roughened with a new file (triangular or flat), the cement applied quickly, and the cemented pieces firmly pressed together. Should this procedure squeeze any cement from the joint over the surface of the glass, it should at once be wiped away with a cloth that is just damp, not wet. For mending cracked bottles or flasks, these should first be warmed so as to expel the air, immediately corked, and the cement at once applied to the cracks. As the bottles cool, the air will be drawn in through the crack, and in this way the cement will be drawn from the surface into the crack itself, where it will harden.
2. For glass upon glass, dissolve, with the aid of jacketed heat, 10 parts of shellac in 2 of turpentine, and to this add 10 parts of finely powdered pumice stone, the cement to be used hot.
3. For glass upon metal, melt together 4 parts of rosin, 1 of wax, and 1 of turpentine. Apply hot.
4. For metal upon glass, melt rosin, 40, turpentine, 3, and plaster of paris, 4. Apply hot.
D. Cements for Leather.
1. For cementing leather belts, make a solution of good glue (I 3/8 test), dissolving 1 part of glue in 4 parts of water. Dissolve, separately, 1 part of tannic acid in 10 parts of water, adding sufficient glycerine to promote solution. Mix the two hot solutions, and heat until the mass is stringy. To apply, have the cement very hot, roughen the edges of the belts with a file, warm them slightly, and the moment the cement has been applied, press them well together by means of a heavy weight and permit them to dry two or three days.
2. Gutta-percha, 6 parts; asphaltum, 6 parts; oil of turpentine, 1 part. The ingredients are to be carefully melted together and the cement applied hot.
3. For cementing strips of very thin leather, cloth to leather, or cloth to cloth, make a solution of elastic bands in benzine. This is best effected by filling a bottle with the elastic bands, pouring in benzine, corking the bottle and subjecting the contents to alternate shaking and rest, until solution has been effected. A better solution may be made by preparing a solvent of 1 part benzine and 2 parts carbon-tetrachloride. Such a mixture is not only a better solvent for the rubber, but possesses the additional advantage that it is non-inflammable, refusing to ignite even if a lighted match is applied directly to it. Chloroform may be used in place of the carbon tetrachloride, in the same proportion, with equally satisfactory results.
E. Cement for Wood.
1. For wood that may not be glued on account of exposure to the air, dissolve shellac with as little wood alcohol as is necessary to effect solution. The cement is to be applied to both pieces, and pressed firmly together.
2. For attaching metal letters to wood, or wood to metal, a solution of glue should be incorporated with some good varnish, turpentine being used in sufficient quantity to effect a proper emulsion.
3. A cement for wood, resisting the action of alkalies and acids, may be prepared by mixing equal parts of rosin, asphaltum, and brick dust, melting these carefully together.
F. Cements for Bone.
1. For ivory and bone, melt at a low heat 2 parts of Japan wax, 2 parts of rosin, and, when these are melted, add sufficient turpentine of good quality, to reduce the melt to a syrup consistency.
2. For knife handles, incorporate equal parts of rosin, sulphur, and iron filings. This is to be used hot, and the knife which is to be cemented to the handle should be heated previous to the application of the cement.
Flexible Glue and Padding Composition. This preparation is indispensable in the binding of books and in the manufacture of writing-pads or tablets. It is used also for the manufacture of certain small toys, such as the grotesque faces vended by street-fakirs. To prepare it, select a strong glue, not less than 1 X in test and preferably A Extra. It is best to have this thick cut, in order that uneven softening may be prevented, owing to the fact that the glue has not been evenly wet.
The glue is to be softened in the water and then melted uniformly at as low a temperature as possible. The glycerine is then well stirred in. The melt is to be cast in shallow pans, from which it may be removed when set. This mixture must be preserved by the addition of pure crystal carbolic acid, dissolved in a little glycerine and water. To disguise the odor of the preservative, perfume with some essential oil such as rosemary, sassafras, or wintergreen.
The procedure is exactly as above. Same materials used to perfume it.