Adhesive

“ But I believe that of all, the Turkish cement already described, which is made of gum MASTIC (a term improperly applied in France to putty, by Americans to lime-plaster on houses, and by Levantines to spirit with resin in it) , is the most adhesive and resistant to heat, cold, or moisture.
The art of mending does not consist so much of knowing what to use for an ADHESIVE (since, as I have said, every chemist’s shop abounds in these) as in skill and tact with which fragments are brought and kept together, missing portions supplied, and in knowing the substance with which to fill a blank. ”

“ To prepare a plate for etching it is first covered with etching-ground, a composition which resists acid. The qualities of a ground are to be so adhesive that it will not quit the copper when a small quantity is left isolated between lines, yet not so adhesive that the etching point cannot easily and entirely remove it; at the same time a good ground will be hard enough to bear the hand upon it, or a sheet of paper, yet not so hard as to be brittle. ”

“ The mixture of equal parts of rubber and petrolatum is of a soft jelly consistence, not especially adhesive, but when incorporated with the lead oleate furnishes a very adhesive plaster. While at first 5 per cent of each rubber and petrolatum was used, it has been found that the petrolatum would melt and exude around the edges of the plaster when applied to the skin, and the quantity was therefore reduced to 2 per cent of each. This mass affords a plaster which is readily adhesive to the body, does not run nor become too soft. ”

“ The adhesiveness of different qualities of glue varies considerably; the best adhesive is formed by steeping the glue, broken in small pieces, in water until they are quite soft, and then placing them with just sufficient water to effect solution in the glue-pot. The hotter the glue, the better the joint; remelted glue is not so strong as the freshly prepared; and newly manufactured glue is inferior to that which has been long in stock. ”

“ But if, while the glue is soft, we pour, say, a teaspoonful of nitric acid into half-a-pint of glue, it will remain soft a much longer time—which is a valuable secret to many, especially where large, broad surfaces of veneers are to be glued on, and where, the process being slow, it is desirable for the adhesive to remain soft for many minutes. ”

“ Adhesive attraction, ~ between surfaces of sensible extent, or by the medium of an intervening substance.
(2.) Cohesive attraction, ~ between ultimate particles, whether like or unlike, and causing simply an aggregation or a union of those particles, as in the absorption of gases by charcoal, or of oxygen by spongy platinum, or the process of solidification or crystallization. The power in adhesive ~ is strictly the same as that of cohesion. ”

“ By heating, the glue dissolves rapidly and remains liquid, when cold, without loss of adhesive power. Any desirable consistence can be secured by varying the amount of saccharate of lime. Thick glue retains its muddy color, while a thin solution becomes clear on standing. ”

“ Their power of adhesion is remarkable, and must have been felt by every one who has handled the species with the fingers; they cling around the flesh with the most annoying tenacity, so that it is no easy matter to cleanse one's hand of them. In what resides this adhesive power? Doubtless in the barbed threads which are sheathed in innumerable myriads in every filament. ”

“ The mending of broken glass is in most cases much the same as that of broken crockery or porcelain. The cement made from mastic, or mastic combined with sturgeon’s bladder, or generally of silicate with whiting, is the proper adhesive. As silicate of soda is simply liquid glass, it can be employed to fill spaces or to make glass ”

“ Coating Material.—The ingenious method for producing an absolutely even surface on paper by the use of a mixture of clay or other mineral substance and an adhesive like glue or casein brushed on to the surface of the paper, is responsible for many of the complaints about the papers of the present day. ”

“ This cement is applicable to glass, wood, or metal. Like the following, it has the advantage of being always ready to use, and requires no boiling. If it becomes too hard to use freely, let so much of it as is required steep for a time in water. Many think, from merely dampening it in the mouth when it is hard, and using it immediately, that it is a very weak adhesive, which is a mistake. A great deal of that sold by the stationers is, however, of very inferior quality, and made with very common glue. ”

“ Much glue is converted into "size," which is a weak gel used as a filling rather than as an adhesive agent. A low-grade glue is often therefore preferred for such purposes, as having "body" rather than "strength." ”

“ Adhesive Cements.—Mixtures of animal, vegetable and mineral substances are employed in great variety in the arts for making joints, mending broken china and other objects, &c. A strong cement for alabaster and marble, which sets in a day, may be prepared by mixing 12 parts of Portland cement, 8 of fine sand and 1 of infusorial earth, and making them into a thick paste with silicate of soda; the object to be cemented need not be heated. ”

“ Where our object is simple support, we should of course select a plaster which is the most adhesive and the least irritating. Many plasters which have gained great celebrity for their curative virtues will be found to owe all their powers to their adhesiveness, such is the Emplastrum Oxidi Ferri Rubri of the Edinburgh Pharmacopœia, for it is impossible that the iron should communicate any tonic effect. ”

“ By itself liquid glass can only be used for mending glass; but when combined with other substances, such as cement, calcined lime, or clay, or glass, in powder, it forms a body as hard as stone, or a double silicate, which is 8 strongly resistant to chemical influences.” It occupies the first position as an adhesive for glass, nor is it surpassed as a cement in solid form. ”

“ The effect of the bleaching upon the fibre is, to disengage part of the adhesive matter, which connects the fine filaments together, and render the yarn susceptible of longation, between the receiving and delivering rollers in spinning, after it has passed through the hot water ”

“ Common black or dark glue, while possessing all the adhesive and other essential qualities of fine colored glue, has heretofore, owing to its color, been confined in its use to such purposes in the arts where color was not essential. ”

“ Coated-paper Troubles.—Coated papers have their characteristic shortcomings. The picking of small particles of the coating is perhaps the most common fault, and is caused by insufficient adhesive elements in the coating mixture. Other troubles are traceable to some of the defects of the body stock. Irregularity of the finish is sure to come from faulty application of the coating or careless calendering. Grit or bubbles in the coating is likely to result in a porous surface. The sour odor of some coated papers is due to decomposing casein or glue. ”

“ This is to be done by applying to the glass slide round the object some adhesive substance, and with the forceps placing the thin glass cover (quite dry and clean) upon it. A gentle pressure round the edge will then ensure a perfect adhesion, and with ordinary care there will be little or no danger of breakage. For this purpose gold-size is frequently used. The asphalt and india-rubber varnish also will be found both durable and serviceable. Whatever cement may be used, it is well to allow it to become in some measure “fixed” and dried ”

“ This is the reason why good sound glue made from scraps of skin is preferred by those artisans who may be considered the principal consumers, such as cabinet-makers, carpenters, turners, instrument-makers, wood-carvers, carriage-builders, brush-manufacturers, bookbinders, paper-manufacturers, etc., all of them requiring glue of the greatest possible adhesive power. ”

“ But as the intense degree of heat which is requisite to induce this adhesive quality is accompanied by the production of a molten oxide of iron that clings tenaciously to the white-hot surfaces of the iron, the union will not be complete unless every particle of the adhesing molten scoriae is thoroughly discharged and driven out from between the surfaces we desire to unite by welding. ”

“ Preventing The Putrefaction Of Strong Glues.—The fatty matter always existing in small quantity in sheets of ordinary glue affects the adhesive properties and facilitates the development of bacteria, and consequently putrefaction and decomposition. ”

“ However gentle the contact, adhesion is at once established. When I lift the straw, the threads come with it and stretch to twice or three times their length, like a thread of india-rubber. At last, when over-taut, they loosen without breaking and resume their original form. They lengthen by unrolling their twist, they shorten by rolling it again; lastly, they become adhesive by taking the glaze of the gummy moisture wherewith they are filled.
In short, the spiral thread is a capillary tube finer than any that our physics will ever know. ”

“ If we wet the surfaces of two pieces of glass, and place them in contact, we shall find that they adhere to each other, and that, independently of the effect of the pressure of the air, they oppose considerable resistance to any attempt to separate them. Again, if we bring any substance, as the blade of a knife, in contact with water, the water adheres to the blade in a thin film, and remains, by what is termed adhesive attraction. This property resides in the surface of bodies, and is in proportion to the extent of its surface. ”

“ The powder of cocoa-nut shells, slate, of paper, plaster of Paris, of leather, clay, lime, fine sand, and many other substances, can all be combined with adhesives, acids, or chemical solvents in such a manner as to form what may be called generically cements, or substances, or pastes, which become hard. Any glue or gum, or liquid which will make two surfaces adhere, can be mixed with most organic or inorganic hard substances in powder so as to form a paste which, when dry, forms a solid, hard substance, because the grains of the powder are thereby cemented together. ”

“ This is effected either with wire or by a composition of tar and rosin. The wire is used in all cases in which the fibre is doubled; but when the bristles are required in their full length, as in sweeping-brushes, the adhesive substance is employed.
8. It is superfluous to enter into detail, to show the manner in which the wire and composition are applied in fixing the bristles, as any person, with an ordinary degree of observation, can readily comprehend the whole, by examining the different kinds of brushes which are met with in every well-regulated household. ”

“ The reader can easily satisfy himself by experiment that these artificial woods made from sawdust or shavings, combined with adhesives, are very easy to manufacture, very cheap, and, when properly made, 69 extremely strong. When strong pressure or rolling can be applied, the quantity of adhesive may be diminished. Linen or muslin rags, cotton-wool, or any textile fabric can be added to the shavings, as well as waste-paper of all kinds. Anything fibrous or stringy will aid in the binding. ”

“ Do not use thick glue for joints or veneering. In all cases work it well into the wood in a manner similar to what painters do with paint. Glue both surfaces of your work excepting in the case of veneering. Never glue upon hot wood, as it will absorb all the water in the glue too suddenly, and leave only a very little residue, with no adhesiveness in it whatever. ”

“ Liquid Glues. These are chiefly combinations of glue with some ingredients added to destroy the gelatinizing property and yet not impair its adhesiveness. They remain for a long time clear and syrupy, and are used for a variety of purposes. Below are given a few receipts for such glues.
1. Dissolve 38 parts of glue in small pieces in 100 parts of acetic acid. Solution is promoted by exposing the vessel to the sun or placing it in hot water. ”

“ Expose no more of the made glue to the atmosphere for any length of time than is necessary, as the atmosphere is very destructive to made glue.
All glue, as received from the factory, requires the addition of water before it will melt properly, and every addition of water (while the glue is fresh made) will, up to a certain point, increase its adhesiveness and elasticity. Some glues will bear more water than others, but all will bear more water than usually falls to their share, and that, too, with a greater improvement in the quality of the work. ”

“ Adhesives for Various Uses.—Waterproof glue. Use a good quality of glue, and dissolve it in warm water, then add one pound of linseed oil to eight pounds of the glue. Add three ounces of nitric acid.
Leather or Card-board Glue. After dissolving good glue in water, to which a little turpentine has been added, mix it with a thick paste of starch, the proportion of starch to glue being about two to every part of glue used. The mixture is used cold.
A fine Belt Glue. Dissolve 50 ounces of gelatine in water, and heat after pouring off the excess water. ”

“ Exports of these products, usually in the form of enamels, varnishes, and lacquers, have been appreciable and are probably increasing each year. Official statistics are not reported separately.
TAR-ACID RESINS IN ADHESIVES
A comparatively new use for tar-acid resins is in the manufacture of wood adhesives. Ordinary vegetable and animal glues have long been used, although their deficiencies in certain characteristics are well known. ”