The great variety of substances entering into the manufacture of cements and pastes makes a division of them extremely difficult. Stohmann divides them into the following groups:

1. Oil cements.
2. Resinous cements.
3. Cements containing rubber or gutta percha.
4. Cements containing glue, or starch paste.
5. Lime cements.

Generally speaking, this division is correct; the only change we would suggest is to apply the term agglutinant or paste to bodies containing glue and starch paste.

When we attempt a division of the cements according to the bodies to be cemented, we find that the result will be a larger number of groups; as we must take into consideration whether the articles to be cemented have to be heated or not, whether they are to come in contact with water or other liquids, and other circumstances which would necessitate modifications in the composition of the cements themselves.

According to this, we might group the cements as follows:

1. Cements for glass and porcelain, for repairing broken articles, for fastening glass letters upon show-windows, etc.

2. Cements for metals not exposed to an increase of temperature, for instance, for tightening the joints of gas and water pipes.

3. Cements for stoves and other articles, which have to stand an increased temperature.

4. Cements for chemical apparatus, i. e., such as will have to resist the action of chemical agents.

5. Cements to protect vessels of glass, porcelain, or metal against the action of fire.

6. Cements for filling hollow teeth, for microscopical preparations, and other delicate articles.

7. Cements for special purposes, for instance, for cementing meerschaum, tortoise shell, etc.

Chemical nature of cements. The different varieties of cement frequently contain substances which act chemically upon each other, or upon the bodies to be united with them. To determine the practical availability of a variety of cement for a determined purpose, it is of importance to know the reciprocal behavior of these substances towards each other, as from this we are able to judge at once whether a cement is suitable for a certain purpose or not.

Oil cements. The fluid fats, commonly called oils—though there are oils which remain solid at the ordinary temperature, as, for instance, palm oil and cocoanut oil—may, as regards their behavior on exposure to the air, be divided into two large groups, namely, drying and nondrying oils. As samples of these groups may be mentioned olive oil and linseed oil.

If a thin layer of olive oil protected from dust is exposed to the air, it will remain fluid for years and retain its characteristic oily consistency. The only change it undergoes is that it becomes somewhat more viscid and rancid, and acquires a darker color, but it never dries up.

Linseed oil treated in the same manner solidifies in the course of a few weeks to a hard, tough and elastic mass, resembling, as regards its physical qualities, resin or rubber.

By compounding a drying oil with a small quantity of litharge, pyrolusite, manganous borate, etc., and heating the admixture to the boiling-point, it acquires the property of drying in a few hours when exposed to the air in a thin layer. Oil so treated has been changed to a varnish.

By bringing a drying oil in contact with a body possessing strong basic properties a peculiar process takes place; the sebacic acids contained in the oil combine with the basic bodies to solid combinations which are insoluble in water, and, on exposure to the air, change gradually into masses as hard as stone. Such combinations, as regards their chemical composition, resemble ordinary soap, and for this reason are called insoluble soaps to distinguish them from ordinary soap which is soluble in water.

Burned lime, calcined magnesia, whiting, ferric oxide, litharge, and minium possess the capacity for forming insoluble soaps on coming in contact with drying oils and, still more quickly, with varnishes prepared from them.

The hardness of these soaps in time increases considerably by the oil not saponified drying in. The oil cements are principally used for tightening water and gas pipes, as they resist the action of water, steam and gas.

The only drawback connected with these cements is that they must reach a certain age before becoming entirely hard, and that, on account of the high price of drying oil or varnish which is absolutely required for their preparation, they are rather expensive. The ordinary glazier’s putty and the red lead and linseed-oil cement used in constructing water and gas conduits belong to this group.

Resinous cements. By resins are understood a number of constituents of plants which exude in thick viscous masses through incisions made in the trees, and on exposure to air are gradually converted into less transparent, brittle masses. When heated they melt more or less readily, forming a thick, ropy liquid, and brought in contact with an ignited body they burn with a bright flame and much sooty smoke.

By making incisions in the bark of any of the whole genus of Pinus belonging to the ConiferÆ family, a viscous mass of a strong odor, called turpentine, is obtained. It consists of a solution of common rosin in the essential oil of turpentine, and when distilled yields from 75 to 90 per cent. of colophony or rosin, which remains in the retort, and from 25 to 10 per cent. of the essential oil, commonly called spirits of turpentine. Pure rosin is a brittle, tasteless, and almost inodorous mass of a light yellow color and a smooth, shining fracture.

The various resins found in commerce, such as shellac, mastic, elemi, copal, etc., are formed in a similar manner.

The principal points of importance for our purpose are the different degrees of hardness and brittleness and the melting-points of the various resins. While some possess but slight hardness, for instance elemi, others, such as copal and amber, excel in this respect and their brittleness and high melting-point.

To decrease the brittleness of resins, essential oils are sometimes added, or resinous cements are mixed with oil cements or a fat drying oil, or compounded with rubber cement.

Resinous cements are either softened by heating or entirely melted, or solutions of resins in volatile solvents are used, which, in evaporating, leave the resin behind.

The resinous cements possess great power of resistance, and are therefore well adapted for tightening water and gas pipes, but they have the disadvantage of not standing a high temperature and possessing a certain degree of brittleness which renders them unfit for the cementing of articles exposed to frequent shocks.

Many of these cements, especially those prepared with pitch or asphaltum, can be produced at a very low cost, and do excellent service for water-proofing vessels, water-reservoirs, brickwork, etc.

Rubber and gutta-percha cements. Caoutchouc, commonly called India rubber, or briefly rubber, is derived from the milky juices of certain tropical plants. It is distinguished by great elasticity and indifference to chemical agents.

Both these properties make it a valuable material for cement, and it is much used for this purpose either in the form of solution or as a constituent of other compositions. For cements which are to have a certain degree of elasticity combined with indifference toward chemical agents, it is absolutely indispensable, as no other known body possesses these properties in such a high degree.

The derivation of gutta percha is similar to that of rubber. At an ordinary temperature it forms solid and very tenacious masses, of a leather-like consistency, but at a somewhat higher temperature (below the boiling-point of water) it is converted into a very plastic, soft mass, which can be drawn into very fine threads, and rolled to very thin plates.

By itself or mixed with other substances it furnishes an excellent cement, possessing the valuable properties of tenacity and pliancy when exposed to shocks. As regards resistance to the action of water and chemical agents it is almost equal to rubber, and, for certain purposes, is frequently preferred to the latter.

Glue and starch cements. By itself, i. e., converted by boiling with water into a viscous mass which solidifies on cooling, glue cannot be classed with the cements; the same applies to paste, i. e., starch or flour swelled and boiled in water.

But compounded with other substances both yield excellent cements, in which a part of the properties distinguishing glue solution and paste is preserved. They both possess the property of decreasing the brittleness of many cements, but unfortunately the latter thereby lose their power of resisting the action of water; for starch as well as glue swells in water, and the latter, when moist, passes quickly into putrefaction and destroys the cement.

In a wider sense isinglass, compounds of glue and vinegar, of lime and glue, etc., must be classed with the glue cements, and ordinary flour and shoemakers’ paste with starch cements.

Lime Cements. Lime possesses the property of forming insoluble combinations with egg albumen or caseine, this being the reason why lime cements, of which there are a great number, are generally composed of burned lime and one or the other of the above substances. Lime compounded with a solution of water-glass forms also very solid and durable cements.

Although the cements and agglutinants mentioned in the foregoing are most frequently used, a compound of different cements is often employed, in consequence of which the composition of many cements is very complicated.

In the following we give a description of the preparation of the different kinds of cement, according to the manner of their employment.

Oil cements, as already explained, must be considered as a variety of soaps insoluble in water, formed by the action of drying oils or varnish upon various basic combinations.

The most important of this class is the cement used for securing window-panes. Good glaziers’ putty is a product of extraordinary durability, and, besides for puttying glass and wood, can also be used for joining many other bodies.

Putty. This is prepared by mixing fine whiting with linseed oil or linseed-oil varnish. The whiting should be passed through a sieve of 42 meshes to the inch. It should be perfectly dry before sifting, and be thoroughly incorporated with the oil.

As the work of kneading large masses with the hands or feet must be continued for a long time in order to obtain an entirely uniform product, and is consequently very laborious, it is recommended to use the following contrivance:

Two wooden rollers rest in a suitable frame, and can be brought together or removed from each other by means of two screws. When the mixture of whiting and linseed oil is of sufficient consistency to allow kneading, it is fashioned into a cylinder and rolled out between the above rollers to a long, thin band, which is caught in a vessel. The band is balled together, the ball reformed into a cylinder, and the latter again passed through the rollers, the operation of balling and rolling being continued until a uniform mass is obtained.

The finished product should be kept in oiled paper or under water. White lead is sometimes mixed with the putty, and other pigments to give color as desired. Hard putty may be softened by rolling between the hands.

French putty. Boil 7 lbs. of linseed oil with 4 lbs. of burnt umber for 2 hours. Then add 10 lbs. of white lead and 5½ lbs. of chalk.

Soft putty. Whiting 20 lbs., white lead 2 lbs., linseed oil and olive oil 1 gill each.

Mix the whiting and the white lead with the necessary quantity of linseed oil, to render the putty of the proper consistence, the olive oil being added to the linseed oil before kneading. The object of using olive oil is to prevent the white lead from hardening, and it preserves the putty in a state sufficiently soft to adhere at all times, and not, by getting hard and cracking off, suffering the wet to enter, as is often the case with ordinary hard putty.

Litharge cement. By mixing litharge reduced to a fine powder with linseed oil, a yellow cement is obtained which gradually solidifies to a mass as hard as stone.

Red lead cement is made by mixing red lead with linseed oil to a paste. It is used for cementing the joints of metal pipes.

Lead preparations furnish excellent cements, but have the disadvantage of great weight and a high price. For many purposes a part of the lead combination can be suitably replaced by a substance of less weight, such as whiting, or, still better, burned lime slacked with sufficient water to convert it into a powder.

The quantity of the substitute added varies very much, there being, for instance, many varieties of so-called red lead oil cement, which contain only about 10 per cent. of red lead.

Cement for wash basins. Finely powdered glass (sifted) 2 parts, litharge 2 parts, linseed-oil varnish 1 part.

Wet the powders slightly with the oil, heat and gradually add the rest. Do not use the basin for several days. Finely powdered glass or glass meal may be made by heating glass, throwing it in cold water, grinding the fractured pieces, and washing by stirring up in water, and allowing the finer particles to float off into a second vessel. Collect this fine powder when sufficient has settled in the vessel and sift it through a very fine sieve.

Zinc-white cement is prepared similar to putty or red-lead cement. It may, however, be made as follows: Mastic 2 parts, dammar 4 parts, sandarac 6 parts, Venetian turpentine 8 parts, turpentine 10 parts, benzole 12 parts, zinc white 14 parts.

The resins are powdered, while the Venetian turpentine, ordinary turpentine, and benzole, are put in a bottle, and then the powdered resins put in. The whole is shaken and allowed to stand for the resins to dissolve. The solution is filtered through cotton-wool and rubbed up with sufficient zinc-white to form a cement. Dilute with benzine if necessary.

Mastic cement, mastic or pierres de mastic. Under this name masses are brought into commerce which are well adapted for moulding ornaments, such as figures, columns, etc., to be exposed to the weather. They are comparatively cheap, and it is rather remarkable that they are not more generally known and used for technical purposes.

To prepare large quantities of this cement suitable mills and mixing vessels are required, as the conversion of the materials into a dust-like flour is an indispensable condition of the success of the work. The materials most generally used are fine quartz sand, finely ground calcareous sand, and varying quantities of litharge or zinc oxides, besides as small a quantity of linseed oil as possible.

The linseed oil combines with the litharge or zinc oxide to an insoluble soap, which incloses the other material and forms a mass acquiring the hardness of sandstone in thirty to fifty hours.

After converting the materials into a fine powder, the mixing is accomplished in barrels filled about three-quarters full and revolved by water-power. When a thorough mixture has been effected the pulverulent mass is placed in sheet-iron vessels and saturated with linseed oil, and then moulded at once, as it solidifies in one or two days.

French mastic. Quartz sand 300 parts, pulverized limestone 100, litharge 50, linseed oil 35.

Paget’s mastic. Sand 315 parts, whiting 105, white lead 25, calcined red lead 10, lead acetate solution 45, linseed oil 35.

The mastic may be colored by adding pigments.

Water-proof cement. A. Rubber 7 parts, oil of turpentine 140, linseed oil 40. B. Turpentine 100 parts, sulphuric acid 3, zinc-white 10.

To prepare solution A, place the rubber in the oil of turpentine in a bottle. It swells very much without actually dissolving. After adding the linseed oil, reduce the entire mass by boiling to one-half the volume originally occupied by it.

Solution B is prepared by stirring the sulphuric acid into the turpentine and allowing it to stand for twelve hours. To remove the sulphuric acid, the thick mass which has been formed is then kneaded in water in which the zinc oxide has been distributed. After drying, the resulting mass is dissolved in the warm fluid A.

Another formula is as follows: Linseed oil 8 parts, litharge 12, burnt lime 88.

Boil the linseed oil and litharge half an hour, then stir the lime into the hot mass, and use the mixture hot. This cement is excellent for filling in joints between stones, for flat roofs, water reservoirs, etc. For a better adhesion of the cement, apply a coat of linseed oil varnish to the surfaces to be cemented. Porous stones are made water-proof by heating the cement in a boiler and adding sufficient linseed oil to form a mass which can be readily worked with a smoothing board. Apply as hot as possible.

Serbat’s mastic. Pyrolusite 60 parts, sulphate of lead 60, linseed oil 10.

After thoroughly drying the materials, mix the sulphate of lead with the linseed oil, then add 20 parts of the pyrolusite and, after mixing and working it thoroughly, add gradually the rest of the pyrolusite in small portions and kneading constantly.

Stephenson’s oil cement. Litharge 20 parts, unslaked lime 10 parts, sand 10 parts, hot linseed oil 3 parts.

Alum cement. Dissolve good hard soap, by heating in rain water, dilute the thickly fluid mass and add saturated alum solution as long as a precipitate is formed. Collect the gelatinous precipitate of alumina soap thus formed upon a cloth, and, after draining, pour rain water over it ten to twelve times to remove the salts as much as possible. After washing, dry the alumina soap, and rub it to a fine powder.

To prepare cement rub a portion of the powder with sufficient linseed-oil varnish to form a plastic dough, which is used for filling in the joints.

This cement is water-proof, resists high temperatures without being absolutely fire-proof, and, on account of its light color, is well adapted for joining marble plates, etc.

Oil cement for glass. Litharge 30 parts, burnt lime 20, pipe-clay 10, linseed-oil varnish 6.

Oil cement free from lead for steam pipes. Graphite 12 parts, heavy spar 16, slaked lime 6, boiled linseed oil 6.

Oil cements for steam pipes. I. Litharge 25 parts, air-slaked lime 10, quartz sand 10.

Mix the ingredients quickly with the linseed oil and work the mass thoroughly in a hot mortar. Coat the defective places in the pipes with linseed-oil varnish, apply the cement hot and when partially solid, make it still tighter by heating.

II. Boil 60 parts of graphite, 50 of air-slaked lime, 60 of elutriated heavy spar in 35 of linseed oil, stirring constantly. Apply the mixture hot.

Oil cement for marble. Elutriated litharge 10 parts, brick dust 100, linseed oil 20.

Prepare in the same manner as glaziers’ putty. For various colors add zinc white for white, red lead for red, pyrolusite for brown, etc. Previous to applying the cement saturate the surfaces of the stones to be cemented with linseed-oil varnish.

Oil cement for porcelain. Stir 20 parts of white lead and 12 of white pipe-clay into 10 of boiling linseed oil previously boiled and knead the mass thoroughly. After cementing let the articles stand quietly for several weeks.

Diamond cement. Litharge 30 parts, air-slaked lime 10, whiting 20, graphite 100, linseed oil 40. Apply hot. This is an excellent cement for metal.

Hager’s diamond cement. Whiting 16 parts, elutriated graphite 50, litharge 16.

Mix the pulverized ingredients with sufficient old, thick linseed oil to form a plastic dough.

RESINOUS CEMENTS.

Resinous cement for amber is obtained by melting mastic in linseed oil. Volatile copal lacquer can also be advantageously used for the purpose.

Cement for turners. Melt 1 lb. of rosin in a tin can over the fire, and when melted add 4 ozs. of pitch; while these are boiling add brick dust until, by dropping a little on a cold stone, you think it is hard enough. In winter it may be found necessary to add a little tallow.

By means of this cement a piece of wood may be fastened to the chuck, which will hold when cool, and when the work is finished, it may be removed by a smart blow with the tool. All traces of the cement may be removed from the work by repeated applications of benzine. To use this cement, chip off as much as will cover the chuck to the 1/16th of an inch, spread it over the surface in small pieces, mixing it with ? of its bulk of gutta-percha, then heat an iron to a dull red heat, and hold it over the chuck till the mixture and gutta-percha are melted and liquid. Stir the cement until it is homogeneous, chuck the work, lay on a weight to enforce contact, leave it at rest 20 minutes.

The following cement is much employed and serviceable for the use of turners and artisans in general.

Reduce 1 lb. of whiting to a fine powder, and heat to redness so as to expel all the water. When cold this is mixed with 1 lb. of black rosin and 1 oz. of beeswax previously melted together, and the whole stirred till of uniform consistence.

Cement for ivory and bone. Melt at a moderate heat equal parts of white wax, rosin, and oil of turpentine to form a thickly-fluid mass. For coloring the cement add elutriated red lead, ultramarine, etc.

Cement for white enameled clock-faces. Dammar resin 100 parts, copal 100, Venice turpentine 110, zinc white 60, ultramarine 3.

Apply hot and polish when cold and hard.

Cements for glass. 1. Melt carefully 60 parts of bleached shellac and 10 of turpentine. If too thick, dilute with turpentine.

2. Shellac 20 parts, elemi 5, turpentine 10. Prepare as above.

Cement for glass upon glass. Shellac 10 parts, turpentine 2, pulverized pumice stone 10.

Cement for glass upon metal. Melt together 40 parts of rosin, 20 of rouge, 10 of wax, and 10 of turpentine. Apply hot to the surfaces to be cemented.

Cement for metal letters upon glass. Rosin 42 parts, turpentine 4, plaster of Paris 5.

Cement for wood. 100 parts of shellac and 45 of strong spirit of wine.

This cement serves for joining wood, which, on account of exposure to water, cannot be glued. Apply the cement to the surface of one of the pieces, and after placing upon it a piece of tissue paper press upon it the other piece of wood previously coated with the cement.

Cement for knife handles. Melt together 20 parts of rosin, 5 of sulphur, and 8 of iron filings.

Pour some of the hot mixture into the handle, and then push in the knife previously heated.

Cement for petroleum lamps. Boil 12 parts of rosin in 16 of strong lye until it is entirely dissolved and on cooling forms a tenacious solid mass. Dilute this with 20 parts of water, and carefully work into it 20 parts of plaster of Paris. This cement is insoluble in petroleum, and is especially adapted for cementing the glass parts of lamps to the metal. It is also a good material for stoppers for petroleum bottles.

Cement for porcelain. Rosin, 14 parts; elemi, 7; shellac, 7; mastic, 7; sulphur, 42; brick dust, 20.

Cement for porcelain which is to be heated. Heat carefully 10 parts of amber in a large spoon, stirring constantly, until it evolves heavy vapors of a strong odor. Rub the melted mass as finely as possible, and after placing the powder in a bottle pour over it a mixture of bisulphide of carbon and benzine. Close the bottle air-tight to prevent the evaporation of the very volatile solvent. When the powder is dissolved remove the cork and replace it by one provided with a small brush. The application of the cement and pressing together of the parts to be cemented must be effected as quickly as possible. In articles properly cemented the joint can only be detected by the closest examination. This cement holds so well that cups and saucers, soup-tureens, etc., mended with it can be used for years.

Cement to withstand the action of petroleum. Dissolve 5 parts of shellac, 1 of turpentine in 15 of petroleum. This cement is quite elastic.

Cement for mica. A colored cement for joining sheets of mica is prepared as follows: Soak clean gelatine in water, and when swelled squeeze out the excess of water by pressure between a cloth, then melt the gelatine by the heat of a water-bath, and stir in just enough proof spirit to make it fluid. To each part of this solution add, while stirring, ¼ oz. of gum ammoniac and 1½ ozs. of gum mastic dissolved in 4 ozs. of rectified alcohol. Put the mixture into bottles, and when required for use stand the bottle in hot water. This cement resists cold water.

Cement for horn, whalebone and tortoise shell. Dissolve gum mastic 10 parts and turpentine 4, in 12 of linseed oil. Apply hot.

Cement for terra-cotta articles. Melt together 70 parts of rosin, 70 of wax and 16 of sulphur, and stir into the mass 8 parts of hammer slag and 8 of quartz sand. Coat the fractured surfaces with oil of turpentine, apply the cement as quickly as possible, and press the surfaces together. It is advisable to heat the terra cotta previously to 158° or 176° F. After cementing the article, smooth the joint with a heated knife and dust very fine terra-cotta powder through a linen bag upon the soft cement in order to give it exactly the same color as the article itself.

Mastic cement for glass. Gum mastic 15 parts, bleached shellac 10, turpentine 5.

This mass sufficiently diluted with hot oil of turpentine furnishes an excellent cement for fractured glass and gems. Being colorless, the joint can scarcely be detected, provided the cementing has been skilfully done.

To attach gems to glass of the same color, the cement is colored with aniline colors dissolved in spirit of wine, care being had to give it the same shade as the gem and the glass.

Stick mastic cement. Melt together, at as low a temperature as possible, 10 parts of mastic and one of turpentine, and pour the mass into suitable moulds.

For use, heat the fractured surfaces of the article strongly, so that the cement on being rubbed over them melts, then press the surfaces together and continue the pressure until the cement solidifies.

Sulphur cement for porcelain. White pitch 18 parts, sulphur 28, bleached shellac 4, gum mastic 8, elemi 8, glass meal 28. Melt all together, except the glass meal and stir the latter into the melted mass.

Insoluble cement for wooden vessels. Melt together 60 parts of rosin, 20 of asphalt, and 40 of brick dust. Pour the hot mixture into the joints. This cement resists the action of lye, quick lime, sulphuric and hydrochloric acids.

RUBBER CEMENTS.

These cements are very useful, but owing to the inflammable nature of the components, great care should be taken to guard against fire while preparing them. They should never be made near a naked fire, as the benzine, carbon disulphide or chloroform used to dissolve the rubber is very volatile, and the vapor given off permeates the air until, coming near a source of light, the whole air becomes one vivid sheet of flame. Vessels which are used should be closed, and if possible put out of doors. If heat is required to assist the solvent action, use a sand or hot-water bath, but on no account bring near a fire.

Cements for glass. I. Rubber 1 part, gum mastic 12, dammar 4, chloroform 50, benzine 10.

II. Rubber 12 parts, chloroform 500, gum mastic 120.

This cement adheres immediately, and possesses a high degree of elasticity. It may be used to advantage for joining together the glass panes of hot-houses.

III. Dissolve, without application of heat, rubber 2 parts and gum mastic 6, in 100 of chloroform. This cement is perfectly transparent. It should be applied as quickly as possible, as it sets in a very short time.

Soft rubber cement. Melt 10 parts of tallow in a brass pan and gradually add 150 parts of rubber in small pieces, and stir constantly until all the rubber is dissolved. Keep in readiness a well-fitting lid to be able to extinguish the flame immediately in case the rubber catches fire. When all is melted stir in 10 parts of slaked lime.

This cement is especially adapted for sealing bottles containing caustic substances, such as nitric acid, etc. It remains always tenacious, being therefore suitable for cementing bodies exposed to repeated shocks.

Hard rubber cement. Rubber, 150 parts; tallow, 10; red lead, 10.

This cement is prepared in the same manner as the above. The addition of red lead gives it a red color, and solidifies it in a short time to a mass as hard as stone.

Elastic cement. Carbon disulphide, 8 ozs.; fine rubber, 1 oz.; isinglass, 4 drachms; gutta-percha, 1 oz. Dissolve the solids in the fluid.

This cement is used for cementing leather and rubber. For use the leather is roughened and a thin coat of the cement applied and allowed to dry completely; then the two surfaces to be joined are warmed and placed together and allowed to dry.

Marine glue. This cement, which is only a glue in name, is water-proof, and can be used to cement metal, wood, glass, stone, pasteboard, etc., and is especially adapted for caulking vessels.

Suspend 10 parts of rubber inclosed in a bag in a vessel containing 120 parts of refined petroleum, so that only half of the bag is immersed, and allow it to remain ten to fourteen days in a warm place. Then melt 20 parts of asphalt in an iron boiler and add the rubber solution in a thin jet, and heat the mixture, while constantly stirring, until it is perfectly homogeneous. Pour it into greased metallic moulds, where it forms into dark-brown or black plates difficult to break. In using it, it should be melted in a kettle placed in boiling water to prevent its burning, which it is very apt to do, as it is a bad conductor of heat. After it has been liquefied remove the kettle from the water and place it over a fire, where it can be heated, if necessary, to make it more fluid, to 302° F., carefully stirring it to prevent burning.

If possible, the surfaces to be glued together should be heated to 212° F., as the glue can then be slowly applied. The thinner the layer of glue in cementing together smooth surfaces, the better will it adhere. But a somewhat thicker layer is required for rough surfaces, for instance, boards not planed, the excess of glue being forced out by strong pressure. Generally speaking, it is best to subject all articles cemented together with marine glue to as strong a pressure as possible until the glue is congealed.

Repeated experiments have shown that with the aid of this cement square vats perfectly water-tight can be constructed of boards. Wooden pegs dipped in the compound should be used for putting the vats together.

Jeffrey’s marine glue. Dissolve 1 part of rubber in benzine, and mix the solution with 2 parts of shellac by the assistance of heat.

Another formula is as follows: Coal naphtha 1 quart, rubber cut in shreds 2 ozs. Macerate for 10 or 12 days and then rub smooth with a spatula on a slab; add 2 parts by weight of shellac to 1 part of this solution. To use the compound melt it at about 240° F.

Marine glue for damp walls. Rubber 10 parts, whiting 10, oil of turpentine 20, carbon disulphide 10, rosin 5 and asphalt 5. Dissolve the ingredients in a suitable vessel and stand in a warm place, shaking it frequently.

Scrape the wall smooth and clean, and apply the glue with a broad brush on the damp place and about 8 inches higher than the line of dampness. Before the glue is dry lay on plain paper which will adhere tightly. On this plain paper the wall paper can be pasted in the usual manner. If carefully done, the wall paper will always remain dry.

GUTTA-PERCHA CEMENTS.

Cement for leather. Gutta-percha 100 parts, pitch or asphalt 100, oil of turpentine 15.

This cement should be used hot. It is suitable for cementing all kinds of substances, but adheres particularly well to leather.

Cement for hard rubber combs. A. Prepare a very thick solution of bleached gutta-percha in bisulphide of carbon.

B. Dissolve sulphur in bisulphide of carbon.

The cementing is effected by applying solution A to the fractured surfaces and pressing them together. When dry brush solution B over the cemented place.

Elastic gutta-percha cement. Dissolve 10 parts of gutta-percha in 100 of benzine, then pour the clear solution into a bottle containing 100 parts of linseed-oil varnish and unite both by shaking. This cement excels in elasticity, and is especially suitable for attaching the soles of shoes, as it is so elastic that it will not break, no matter how much it is bent. To make it adhere tightly roughen the leather on the side to be cemented.

Cement for horses’ hoofs. For filling cracks and fissures in horses’ hoofs a cement is required which possesses great resistance to the action of water combined with elasticity and solidity. A mass answering all demands consists of 10 parts by weight of gum ammoniac and 20 to 25 of purified gutta-percha. Heat the gutta-percha to between 194° and 212° F., and then work it with the finely powdered gum ammoniac to a homogeneous mass. In using it, soften the cement by heating, and after carefully cleansing the crack in the hoof, apply it with a heated knife. The cement solidifies immediately after cooling to the ordinary temperature, and becomes soon so hard as to allow of nails being driven into it.

Cement for crockery. Gutta-percha 1 part, shellac 1.

Place the two ingredients in an earthenware jar, and melt the two together by standing this jar on a vessel of boiling water, or else one filled with hot sand, the vessel holding the water or sand being heated over a fire or gas furnace. Stir the melted ingredients well together. The resulting cement is one possessing great hardness and toughness, which suits it admirably for mending crockery. Warm the edges to be joined together, smear the cement on, join together, and hold the article thus joined until cool.

Cement for leather. Mix 10 parts of carbon disulphide with 1 part of turpentine, and then add sufficient gutta percha to make a tough, thickly-fluid mass. Before using this cement, free the surface to be joined from grease. To effect this, sprinkle a little bicarbonate of soda, carbonate of ammonia or borax on the surfaces to be joined, lay a cloth over them, and then place a hot iron on top, and keep it there a short time so as to cause the alkali to cut the grease, then put the cement on both surfaces to be joined, put them together and subject to pressure until they are cemented.

Gutta percha dissolved in carbon disulphide to the consistency of syrup is also a good cement for joining leather. The parts to be joined should be well covered with cement so as to fill the pores of the leather, then the cement is heated and the parts hammered until the cement is cold.

CASEINE CEMENTS.

Preparation of pure caseine. Although the caseine contained in old cheese can be used, the other constituents, such as fat, salt, and free acid, exert an injurious influence upon the solidity of the cement prepared with it. It is, therefore, best to prepare pure caseine, which is easily accomplished in the following manner:

Put milk in a cool place, and after taking off the cream as long as any is formed, remove the skimmed milk to a warm place to coagulate. After heating the curd, place it upon a filter and wash the caseine remaining upon the filter with rainwater until the water running off shows no trace of acid.

To remove the last traces of fat tie the washed caseine in a cloth and after boiling it in water, spread it upon blotting paper in a warm place to dry. It will shrivel up to a horny mass.

When thoroughly dried pure caseine will keep for a long time without suffering alteration. To obtain the caseine in a form suitable for preparing cements it is only necessary to pour water over a corresponding quantity and allow it to stand for some time. Caseine combines with lime to a hard insoluble mass.

Ordinary technical caseine may be readily and cheaply prepared as follows: Skim milk is heated in a copper boiler, if necessary by the introduction of steam, to 122° F. Then add for every 1000 quarts of milk, 3 quarts of crude hydrochloric acid diluted with 5 to 6 times the quantity of water. After coagulation, the whey is drained off, the curd spread out upon an inclined table and allowed to cool. The curd is then washed by pouring cold water over it through a rose, or stirring it up with water in a barrel, allowing to settle, and pouring off the supernatant water. The residue is subjected to moderate pressure. The caseine while still moist is comminuted in a curd-mill and packed in bags. In this state it must be worked at once, as otherwise it spoils readily and is attacked by worms. If it is to be kept for a longer time, it has to be dried. This is effected by spreading it out upon linen cloths and placing it in a drying chamber.

In this manner 8.5 per cent. of moist, or 3.5 per cent. of dry, caseine is obtained which is brought into commerce as technical caseine or lactarine. It being insoluble in water, 10 per cent. of an alkali—soda, borax, or ammonia—has to be added to effect solution. Water-soluble caseine is seldom found in commerce, the consumer preparing it, as a rule, himself.

A purer technical caseine is obtained according to John A. Just’s method as follows: Dissolve, stirring constantly, in 115 quarts of water heated to between 104° and 131° F., 17 to 26 ozs. of bicarbonate of soda and 176 lbs. of moist, or 118 lbs. of dry, caseine, and dry the solution upon a heated revolving metal cylinder. After each revolution of the cylinder, the dry material is scraped off with brushes and by being forced through a fine-meshed sieve yields soluble caseine powder.

Caseine cement which can be kept for a long time. Convert into powder, each by itself, 200 parts of caseine, 40 of burned lime, and 1 of camphor. Mix the powders intimately and keep the mixture in an air-tight bottle. For use, mix some of the powder with the requisite quantity of water and use the cement at once.

Cement for glass. Old dry cheese 100 parts, water 50, slaked lime 20.

Free the cheese from rind, and rub it with the water until a homogeneous mass drawing threads is formed. Then stir in quickly the lime powder, and use the cement at once. It unites not only glass to glass, but can also be used for cementing metal to glass.

Cement for metals. Elutriated quartz sand, 10 parts; caseine, 8; slaked lime, 10, and sufficient water to form a cream-like mass.

Cement for porcelain. Caseine dissolves readily in solution of water-glass, and forms then one of the best cements for porcelain known. To prepare it, fill a bottle one-quarter full with fresh caseine, and after filling the bottle with solution of water-glass, effect the solution of the caseine by frequent shaking.

Cement for meerschaum. Dissolve caseine in water-glass, and after stirring quickly finely-pulverized calcined magnesia into the mass, use it at once, as it solidifies very soon. By adding, besides magnesia, genuine meerschaum finely pulverized, a mass closely resembling meerschaum is obtained, which can be used for manufacturing imitation meerschaum.

Cement for wood, etc. Rub 10 parts of caseine and 5 of borax to a thick, milky mass, and use it like glue. This cement can be advantageously used for pasting labels upon wine bottles, as it neither moulds nor becomes detached in the cellar.

Another formula is as follows: Dissolve borax by boiling in water, and pour the solution over fresh caseine. The result will be a clear, thick mass of extraordinary power of adhesion, which can be kept for any length of time without suffering decomposition.

Applied to leather, paper, linen or cotton goods, it forms a coat of beautiful lustre, and for this reason is much used in the manufacture of fancy articles of paper and leather.

Cement for porcelain. Dissolve 10 parts of caseine in 60 of water-glass solution. Apply the cement quickly and dry the cemented articles in the air.

WATER-GLASS AND WATER-GLASS CEMENTS.

Water-glass. Water-glass (silicate of soda or soluble glass) is found in commerce as a thickly-fluid, tenacious mass. It is generally prepared by fusing 15 parts of quartz sand with 8 of carbonate of soda and 1 of charcoal. The silicic acid combining with the soda disengages the carbonic acid, the expulsion of which is facilitated by the presence of charcoal, which converts it into carbonic oxide. It dissolves readily in water. The solution has a strongly alkaline taste, and possesses the property of being gradually converted, on exposure to the air, to a gelatinous mass which finally solidifies. For this reason water-glass should be kept in bottles hermetically closed with corks. Glass stoppers are of no use, as they are so firmly cemented to the bottle that on attempting to open the latter the neck breaks off.

By combining water-glass with cement or burned lime the resulting mass solidifies quite rapidly to a mass as hard as stone, and generally capable of resisting chemical action.

Water-glass by itself is only fit for cementing glass to glass, but combined with other substances it furnishes very durable and solid cements.

Cement for cracked bottles. Select a cork which will fit the bottle air-tight and place it loosely upon the bottle, and heat the latter gradually to at least 212° F. Then press the cork down and apply a thick solution of water-glass to the cracks. In cooling, the air in the bottle contracts strongly, and the pressure of the exterior air drives the water-glass with great force into the cracks closing them entirely so that they cannot be detected.

Cement for glass and porcelain. Stir quickly together 10 parts of elutriated glass meal, 20 of powdered fluor spar, and 60 of water-glass solution, and apply the homogeneous paste at once. In a few days the cement will be so hard that the cemented vessels can be heated without danger.

Cement for hydraulic works. Finely powdered cement, and solution of water-glass. Mix the two bodies quickly together.

As this cement hardens very quickly, it should be used fresh. It hardens under water, and is therefore excellent for hydraulic works. The stones should be coated with a solution of water-glass before applying the cement.

Cement for uniting metals. A strong cement, which hardens rapidly, is made by stirring the finest whiting in a solution of soda-glass of 33° B., made so as to form a plastic mass. This can be readily colored to any desired shade. The addition of sifted sulphide of antimony gives a black cement, which by polishing acquires a metallic lustre; iron filings render it grayish-black; zinc dust turns it green, but after polishing, it appears like metallic zinc, and may be employed for the permanent repair of zinc ornaments, etc. Carbonate of copper imparts a light green shade. Other additions may be made, as oxide of chrome for dark green, cobalt blue for blue, red lead for orange, vermilion for scarlet, carmine for violet, etc.

Cement for tightening joints of pipes exposed to a red heat. Mix 80 parts of pyrolusite, 100 of zinc white, and 20 of water-glass.

This cement fuses at a temperature not too high, and then forms a glass-like mass which adheres very firmly and closely.

Cement for marble and alabaster. The point of fracture of articles cemented with the following mixture is difficult to find, and the cemented place is much stronger than the material itself. Mix 12 parts of Portland cement, 6 of slaked lime, 6 of fine sand, and 1 of infusorial earth with sufficient water-glass to form a thick paste. The article to be cemented need not be heated. It hardens in twenty-four hours.

GLYCERINE AND GLYCERINE CEMENTS.

Commercial glycerine is a yellowish or nearly colorless and more or less viscid liquid having an intensely sweet taste. In combination with lead oxide and intimately worked into it, by heating and stamping, it furnishes very strong and durable cements deserving general introduction, though thus far they have been but little used.

For the manufacture of cements the use of pure odorless glycerine is not required, the yellow crude article, which is much cheaper, answering all purposes. The principal point is to use very highly concentrated glycerine, as otherwise the cements prepared with it solidify very slowly and besides do not possess a proper degree of hardness and solidity.

It is of especial importance to have the lead oxide free from water. To accomplish this, heat it thoroughly and mix it with the glycerine while still hot. Cement thus prepared solidifies very quickly, and can be used for many purposes. It is an excellent material for quickly joining the stones of submarine works.

Glycerine and litharge cement. Moisten elutriated litharge with glycerine so that a thin homogeneous paste is formed. This cement is adapted for uniting the joints of steam pipes, cementing wood, glass, porcelain, and also glass upon metal, etc. It solidifies to a very hard mass in a quarter to three-quarters of an hour. Before applying the cement coat the surfaces to be joined with pure glycerine.

LIME CEMENTS.

Quick lime, slaked lime and chalk are used for this purpose. Quick lime, which is obtained by burning limestone, combines gradually with the fats to insoluble lime soaps. Slaked lime, which consists of a combination of lime with water, acts in the same manner.

For the preparation of cements the lime is slaked by placing it in a dish and pouring as much water over it as it will absorb. Good lime, technically called fat lime, should eagerly combine with water, evolving much heat, swelling greatly, and crumbling to a light white powder.

Quick lime exposed to the air until, by the absorption of moisture and carbonic acid, it is converted into a powder is called air-slaked.

Cements prepared with quick lime will, as a rule, solidify more quickly than those prepared with air-slaked lime.

Chalk is a carbonate of lime consisting of the shells of microscopic animals, and can be readily pulverized and elutriated. In the latter state it is known as whiting. For the preparation of entirely white cements the use of pure white lime or chalk is absolutely necessary. Yellow or reddish lime contains oxide of iron, and furnishes cements of the same tinge.

Cement for glass. Litharge 30 parts, quick lime 20, linseed-oil varnish 5.

Cement for joiners. A cement for filling up cracks and holes is obtained by mixing slaked lime 50 parts, flour 100, linseed-oil varnish 15.

Cement for cracked clay crucibles and porcelain. By applying to the cracks a mixture of 10 parts of slaked lime, 10 of borax, and 5 of litharge in sufficient water to form a stiff paste, and drying after heating the crucible, the cracked places will be united so firmly that the crucible, when thrown to the ground, will generally break in any other place than the cemented one.

This cement can also be used for porcelain capable of standing a strong heat.

Lime and glue cement. Stir air-slaked lime into hot glue. This cement is especially suitable for attaching metal to glass. It forms a very hard yellowish-brown mass.

GYPSUM CEMENTS.

Sulphate of lime in combination with water is met with in nature, both in the form of transparent prisms of selenite, and in opaque and semi-opaque masses, known as alabaster and gypsum. By pulverizing the latter and heating to about 302° F. it loses its water, and is converted into anhydrous gypsum or plaster of Paris, which on mixing with water recombines with it to form a mass of hydrated sulphate of lime, the hardness of which nearly equals that of the original gypsum. When the powder is mixed with water to a cream and poured into a mould, the minute particles of anhydrous sulphate of lime combine with the water to reproduce the original gypsum, and this act of combination is attended with a slight expansion which forces the plaster into the finest lines of the mould.

By using a solution of alum instead of ordinary water, a plaster is obtained which, although it takes much longer to set than the ordinary kind, is much harder, and therefore takes a good polish.

For preparing cements only perfectly white plaster of Paris should be used, as the gray article possesses but little adhesive power.

Cement for plaster of Paris statues. To repair plaster of Paris statues so that the point of fracture cannot be detected, proceed in the following manner:

Moisten the fractured surfaces with water by means of a brush until they absorb no more and remain moist. Mix plaster of Paris with water to a thin cream and stir until the heat appearing at first has ceased, which will prevent the conversion of the plaster into a solid coherent mass. Apply quickly a thin layer of the plaster to one of the fractured surfaces, press the other against it until the plaster has set, and, when dry, carefully remove the excess by scraping.

Cement for glass and porcelain. Mix quickly 50 parts of plaster of Paris, 10 of quick lime, and 20 of white of egg. Use at once, as the cement solidifies very rapidly.

Cement for iron and stone. A very useful cement for securing iron railing in stone is obtained by mixing 30 parts of plaster of Paris, 10 of iron filings and 20 of vinegar.

Cements for porcelain. I. Mix plaster of Paris with saturated solution of alum to a cream. After moistening the fractured surfaces apply a thin layer of the cement, press the surfaces together, wrap a wire or cord tightly around them, and let the article stand quietly for a few weeks. The cement is converted into a mass as hard as stone.

II. Mix plaster of Paris with a thick, clear solution of gum arabic and cement the articles as soon as possible. Although this cement adheres very tightly, porcelain vessels cemented with it cannot be used for liquids.

Universal plaster of Paris cement. Mix 21 parts of plaster of Paris, 3 of iron filings, 10 of water, and 4 of white of egg. This cement is suitable for attaching metal to glass, metal to stone, etc.

IRON CEMENTS.

Heat-resisting cement. Clay 10 parts, iron filings 5, vinegar 2, water 3.

Water and steam-proof cement. Iron filings 100 parts, sal-ammoniac 2, water 10.

This cement rusts very much in a few days, and is converted into an extremely solid mass which is perfectly steam- and water-proof.

Cement for iron. Mix 65 parts of wrought-iron filings, 2.5 of sal ammoniac, and 1.5 of flowers of sulphur, and then add 1 part of sulphuric acid diluted with sufficient water to form a stiff paste. This cement solidifies in two to three days, and rusts, with the parts of iron to be cemented, to an extraordinarily durable mass.

Fire-proof cement for iron pipes. Wrought-iron filings 45 parts, clay 20, fire-clay 15, common salt solution 8.

Cements resisting high temperatures. 1. Iron filings 20 parts, clay powder 45, borax 5, common salt 5, pyrolusite 10.

Dissolve the borax and common salt in the water, add and mix quickly the clay powder, pyrolusite, and iron filings. Apply the cement at once. Exposed to a white heat, it hardens to a tightly adhering, glassy mass.

2. Mix 52 parts of pyrolusite, 25 of zinc white, and 5 of borax with solution of water-glass to a paste, and use at once. This cement requires to be gradually dried. It will stand the highest temperatures.

Cement for filling in defects in castings. Stir 100 parts of iron filings free from rust with sufficient water to form a thick paste, and press the mixture into the fissures, cracks, etc. The cement becomes solid only after the iron filings become strongly rusted. To free the ingredients from adhering fat, wash them, before mixing, in liquid ammonia.

Cement for cracked stove plates, etc. Knead 20 parts of iron filings, 12 of iron scale, 30 of plaster of Paris, and 10 of common salt with blood to a stiff paste, and use at once. Instead of blood, water-glass can be used, it having the advantage of being odorless on strong heating, while blood cement evolves a disagreeable odor.

Cement for iron water tanks. Knead iron filings with vinegar to paste. Allow the mixture to stand until it turns brown, and then force it into the joints by means of a chisel.

Cement for cracked iron pots. Knead 10 parts of iron filings and 60 of clay with linseed oil to a thick paste. Before applying it add a little linseed oil, and allow it to dry slowly. In a few weeks the cement will be so hard that the vessels can be used without danger.

Black cement for stoves. Iron filings 10 parts, sand 12, bone black 10, slaked lime 12, glue water 5.

Cements for iron stoves. 1. Pulverize as finely as possible and mix intimately 4 to 5 parts of clay, 2 of iron filings free from rust, 1 of pyrolusite, ½ of common salt, and ½ of borax with water to a paste, and apply the cement quickly to the places to be cemented and allow it to dry slowly. This cement will stand a white heat, and resist the action of boiling water.

2. Mix intimately and as quickly as possible 1 part of pulverized pyrolusite, and 1 of zinc white with solution of water-glass to a plastic mass, which solidifies quickly. The power of resistance of this cement, it is claimed, is not inferior to No. 1, though experiments have proved No. 1 to be preferable.

CEMENTS FOR CHEMICAL APPARATUS.

Cements to be used for the above purpose must possess various properties difficult to combine in one preparation. They must be gas-proof, and capable of resisting the action of different vapors and acid fluids. As regards resistance to the action of chemical agents, there is nothing better than caoutchouc, but unfortunately it can only be used for tightening chemical apparatus not exposed to a high temperature.

In chemical laboratories bran of almonds, either by itself or kneaded with water to a thick paste, is frequently used, or rye or wheat bran mixed with a little flour and water. These cements, though very suitable for cementing glass distilling apparatus, are strongly acted upon by chlorine and the vapors of nitric acid.

For small apparatus to be used for the development of fluoric acid, plaster of Paris mixed with a little water can be used as a cement. To make the joint entirely gas-tight, paste a strip of paper over it. Although this cement does not resist the action of fluoric acid for any length of time, it suffices generally for the protection of the Workmen during the time the development of the acid is in progress, as, for instance, in chemical analyses, etc.

To cement chemical apparatus exposed to a temperature not exceeding 86° to 104° F. paraffine does excellent service; as it possesses the power of resisting the action of the strongest acids and alkalies.

Below will be found a few receipts for cements which have proved reliable.

Linseed oil and clay cement. Knead 10 parts of dry clay with 1 of linseed oil to a homogeneous mass. This cement will stand heating to the boiling-point of mercury.

Linseed oil, zinc and manganese cement. Knead 10 parts of pyrolusite, 20 of zinc white, and 40 of clay with sufficient boiled linseed oil (not exceeding 7 parts) to a plastic mass. This cement will stand a somewhat higher temperature than the preceding one.

Cements resisting very high temperatures. I. Clay 100 parts, powdered glass 2.

The glass melts on exposure to great heat and slags the clay to a hard mass. The same effect is produced by adding small quantities of soda and borax to the clay. An admixture of chalk and boric acid, as in the following receipt, also gives excellent results.

II. Clay 100 parts, chalk 2, boric acid 3.

Cement resisting acids. Melt rubber with double the quantity of linseed oil, and then knead in sufficient bole to form a paste. This cement resists the action of nitric and hydrochloric acids, and can be advantageously used for closing bottles containing them. As it solidifies very slowly, it can readily be detached from the bottles, and used again.

For cement which is to solidify quickly on exposure to the air, add a few per cent. by weight of red lead or litharge.

Rubber cement for chemical apparatus. Cut 8 parts of rubber in small pieces and throw them gradually into a mixture of 2 parts of tallow and 16 of linseed oil previously strongly heated. After effecting an intimate mixture of the constituents by vigorous and constant stirring, add 3 parts of white bole.

Although this cement does not stand a high temperature, it possesses an extraordinary power of resisting the action of acid vapors.

Scheibler’s cement for chemical apparatus. Melt together 1 part of wax and 3 of shellac, and work into the mixture 2 parts of gutta-percha cut up in very small pieces. This cement will bear considerable heat without actually melting.

CEMENTS FOR SPECIAL PURPOSES.

Cement for attaching metal letters to glass, marble, wood, etc. Dissolve over a water-bath 5 parts of glue in a mixture of 15 parts of copal varnish, 5 parts of boiled linseed oil, 3 parts of crude oil of turpentine, and 2 parts of rectified oil of turpentine, and add 10 parts of slaked lime to the mixture.

Cement for joints of iron pipes. Mix 5 lbs. of coarsely powdered iron borings, 2 ozs. of powdered sal ammoniac, and 1 oz. of sulphur with sufficient water to form a paste. This composition hardens rapidly, but if time can be allowed it sets more firmly without the sulphur. It must be used as soon as mixed, and rammed tightly into the joint.

Another receipt is as follows:

Mix 2 ozs. of sal ammoniac, 1 oz. of sublimated sulphur and 1 lb. of cast-iron filings or fine turnings in a mortar, and keep the powder dry. When it is to be used, mix it with 20 times its weight of clean iron turnings or filings and grind the whole in a mortar; then wet it with water until it becomes of convenient consistency, when it is to be applied to the joint. After a time it becomes as hard and strong as the metal.

Steam boiler cement. Mix 10 parts of finely-powdered litharge with 1 part of fine sand and 1 part of air-slaked lime. The mixture may be kept for any length of time without deterioration. For use a portion of it is made into a paste with linseed oil or, better, boiled linseed oil. In this state it must be applied quickly, as it soon becomes hard.

Cement for rubber. Powdered shellac is softened in 10 times its weight of strong water of ammonia, whereby a transparent mass is obtained, which becomes fluid after keeping some little time without the use of hot water. In three to four weeks the mixture is perfectly liquid, and when applied it will be found to soften the rubber. As soon as the ammonia evaporates it hardens again, and thus becomes impervious both to gases and to liquids. For cementing sheet rubber, or rubber material in any shape, to metal, glass, and other smooth surfaces, this cement is highly recommended.

Cement for tires. 1. Isinglass 1 oz., gutta-percha 1 oz., rubber 2 ozs., carbon disulphide 8 fluid ozs. Mix and dissolve.

2. Shellac 4 ozs., gutta-percha 4 ozs., red lead and sulphur, each ½ oz. Melt the shellac and gutta-percha, and add with constant stirring the red lead and sulphur, melted. Use while hot.

3. Crude rubber 1 oz., carbon disulphide 8 ozs. Macerate 24 hours, and then add a solution of:

Rosin 2 ozs., beeswax ½ oz., carbon disulphide 8 ozs.

4. Rubber 20 parts, rosin 10, Venetian red 10, tallow 5. Melt the rubber over a fire, then add the rosin and the tallow and finally the Venetian red.

Cement for steam pipes, etc. A cement of specially valuable properties for steam pipes, in filling up small leaks, such as a blow-hole in a casting, without the necessity of removing the injured piece, is composed of 5 lbs. Paris white and 5 lbs. yellow ochre, 10 lbs. litharge, 5 lbs. red lead and 4 lbs. black oxide of manganese. Mix the materials thoroughly and make into a paste with a small quantity of asbestos and boiled linseed oil. The composition, as thus prepared, will harden in from 2 to 5 hours, and has the advantage of not being subject to expansion and contraction to such an extent as to cause a leakage afterwards, and its efficiency in places difficult of access is of special importance.

Cement for marble. Stir to a thick batter with silicate of soda 12 parts of Portland cement, 6 of slaked lime, 6 of fine white lead and 1 of infusorial earth. This is excellent for marble and alabaster. The cemented objects need to be heated. After 24 hours the fracture is firm, and the place can scarcely be found.

Cement for attaching wood, glass, etc., to metal. Acetate of lead 23 parts by weight, alum 23, gum arabic 38, wheat flour 250.

Dissolve the acetate of lead and the alum in a little water and separately dissolve the gum arabic in a fair quantity of boiling water. Thus if the 250 parts of wheat flour represent half a pound, the quantity of water needed will be about a pint. The gum having dissolved, add the flour, put the whole on the fire, stir well with a wooden stick, then add the solution of lead acetate and alum. Continue the stirring in order to avoid the formation of lumps, then take it off the fire without allowing it to boil. This cement is used cold, and will not scale. It is very useful in making wood, glass, cardboard, etc., adhere to metal, and is extremely strong.

Brushmakers’ cement. Rosin 5 lbs., rosin oil or spirit 1 quart.

Reduce the rosin to small pieces, run down in a pot, add the other ingredient, and stir until mixed and syrupy, then run out into tins. It is used for cementing the bristles in the stocks, also for string binding on sash tools, etc.

Cement for electrical apparatus. Mix together 1 lb. of beeswax added to 5 lbs. of rosin, 1 lb. of red ochre, and 2 tablespoonfuls of plaster of Paris. It will make an excellent composition for electrical apparatus.

A cheaper composition for cementing voltaic plates into wooden troughs is made with 6 lbs. of plaster of Paris and ¼ pint of linseed oil. The ochre and the plaster of Paris should be well dried and added to the other ingredients when these are in a melted state.

Jewelers’ cement. Dissolve over the water-bath 25 parts of fish glue in a small quantity of strong spirits of wine, add 2 parts of gum ammoniac; separately dissolve 1 part of mastic in 5 of spirits of wine. Mix the two solutions and keep them in well-stoppered bottles.

American cement for jewelers. Soak 4 ozs. of isinglass in 2 lbs. of water for 24 hours, then evaporate in the water-bath; to 1 lb. add 1 lb. of rectified spirits of wine, and strain. Then mix in a solution of 2 ozs. of mastic and 1 oz. of gum ammoniac in 16 ozs. of rectified spirit.

Cement for celluloid. Shellac 2 ozs., spirits of camphor 2, 90 per cent. alcohol 6 to 8.

Stratena. This well-known household cement is said to be prepared as follows: Dissolve 12 parts of white glue in 16 of acetic acid, and then add this solution to one of 2 parts gelatine in 16 of water. After mixing add 2 parts shellac varnish.

Cement for cloth. Gutta-percha 16 parts, rubber 4, pitch 2, shellac 1, linseed oil 2 pints. Dissolve the whole by heat, stirring constantly.

HOW TO USE CEMENTS.

It is unquestionably true that quite as much depends upon the manner in which a cement is applied, as upon the cement itself. The best cement that was ever compounded would prove entirely worthless improperly applied. In the foregoing a number of cements have been given which answer every reasonable demand when properly prepared and properly used. Good common glue will unite two pieces of wood so firmly that the fibres will part from each other rather than from the cementing material; two pieces of glass can be so joined that they will part anywhere rather than on the line of union; glass can be united to metal, metal to metal, stone to stone, and all so strongly that the joint will certainly not be the weakest part of the resulting mass. What are the rules to be observed in effecting these results?

The first point that demands attention is to bring the cement itself into intimate contact with the surface to be united. If glue is employed, the surface should be made so warm that the melted glue will not be chilled before it has time to effect a thorough adhesion. The same is more eminently true in regard to cements that are used in a fused state, such as mixtures of resins, shellac, and similar materials. These matters will not adhere to any substance unless the latter has been heated to nearly or quite the fusing point of the cement used. This fact was quite familiar to those who used sealing-wax in the olden days of seals. When the seal was used, in succession, rapidly so as to become heated, the sealing-wax stuck to it with a firmness that was annoying, so much so that the impression was generally destroyed, from the simple fact that the sealing-wax would rather part in its own substance than at the point of adhesion to the seal. Sealing-wax or ordinary so-called electric cement is a very 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 those itinerant venders of cement for uniting earthenware. By heating two pieces of delf so that they will fuse shellac, they are able to smear them with a little of this gum and join them so that they will rather break at any other part than along the line of union. But although people see the operation constantly performed and buy liberally of the cement, it will be found that in nine cases out of ten, 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, and they are apt to use too much of the material, and the result is a failure.

The great obstacles to the junction of any two surfaces are air and dirt. The former is universally present, while the latter is due to accident or carelessness. All surfaces are covered with a thin adhering layer of air, which it is difficult to remove, and which, although it may at first sight seem improbable, bears a relation to the outer surface of most bodies different from that maintained by the air a few lines away. The reality of the existence of this adhering layer of air is well known to all who are familiar with electrotype manipulation. It is also seen in the case of highly polished metals which may be immersed in water without becoming wet. Unless this adhering layer of air is displaced, the cement cannot adhere to the surface to which it is applied because it cannot come in contact with it. The most efficient agent in displacing this air is heat. Metals warmed to a point a little above 203° F. become instantly and completely wet when immersed in water. Hence, for cements that are used in a fused condition, heat is the most efficient means of bringing them in contact with the surfaces to which they are to be applied. Another very important point is to use as little cement as possible. When the surfaces are separated by a large mass of cement we have to depend upon the strength of the cement itself and not upon its adhesion to the surfaces which it is used to join; and, in general, cements are comparatively brittle.

The cement forced out of the joint by pressing the surfaces together should be removed while the cement is in a fused state or liquid. This can generally be effected by wiping the surplus off, while after solidification a certain amount of force has to be used which may frequently break the joint.

Oil cements, which generally solidify slowly, have the advantage of being water-proof. In cementing with oil cements, coat the surfaces to be joined with linseed oil, or, still better, boiled linseed oil, but in working with resinous cements apply oil of turpentine, spirit of wine, or a fluid which will readily dissolve the cementing constituent of the cement.

For cleansing the surfaces from grease and dirt place the articles in strong lye and rinse off in clean water without touching the surfaces with the hands. For painted porcelain articles which cannot be placed in lye, it is recommended to brush the surfaces several times with carbon disulphide.

PASTES AND MUCILAGES.

Preparation of paste. Ordinary paste is prepared either from flour or starch, and according to the raw material used in its preparation, may, therefore, be divided into starch and flour paste.

Starch is an indispensable constituent of certain parts of plants, and plays an important part in the nutrition of the plant. It is chiefly manufactured from potatoes, Indian corn and grain. Examined under the microscope, it is seen to be composed of small granules consisting of layers placed one above the other.

Starch paste. In stirring starch with water to a thin paste and gradually heating it, it will be observed that at a temperature between 140° and 158° F. a peculiar change takes place; the thin milk-white liquid becomes transparent, opalizes, and at the same time becomes thickly fluid, in short, the starch is converted into paste. During this process the separate layers of the starch granules become detached somewhat in the same manner as an opening bud, whereby they absorb water, and the peculiar mass, called paste, is formed. That paste is not a solution is easily proved by the fact that on attempting to filter starch-paste only water drains off, while the starch remains upon the filter and gradually dries to a horny mass.

Paste left to itself soon decomposes, especially during the hot season of the year; it becomes sour through the formation of lactic acid, butyric acid, acetic acid, and other substances, and loses its adhesive power.

In preparing paste, the following rules must be especially observed: Divide the starch in water by constant stirring so as to form a homogeneous, rather thinly liquid fluid, and then add boiling water in small portions, stirring constantly. The conversion of the starch into paste is recognized by the thickening of the entire mass and the appearance of opalescence, when it is only necessary to add the required quantity of water to give the paste the desired consistency.

If white lumps are observed, it is an indication that the starch has not been thoroughly mixed with the water, and that certain portions of it have remained dry. Paste containing such lumps cannot be applied with any degree of uniformity, and besides it possesses less adhesive power. Nothing can be done to remedy the evil except diluting the paste with a considerable quantity of water and boiling, with constant stirring, until the mass is perfectly homogenous.

Starch paste prepared in a proper manner possesses great adhesive power, and, when applied in a thin layer, dries to an almost colorless coating. Pure starch paste is used for many purposes. It serves not only for pasting paper, wall paper, etc., but also for sizing tissues, such as paper-muslin, linen, etc., in order to give them lustre, body, and, under certain circumstances, greater weight. To increase the weight of linen, white lead or heavy spar is frequently mixed with the starch.

Flour paste. The principal constituent of flour, besides starch, is gluten. It is obtained in a pure state by tying flour in a linen bag and kneading it under water so long as the latter is rendered turbid by particles of starch. The gluten remaining in the bag is a light-brown, very tenacious mass, drawing threads between the fingers, and, as regards its chemical properties, is closely allied to albumen and caseine. Gluten, like the last-mentioned substances, shows a tendency to form combinations with lime which gradually solidify, and it can therefore be used for preparing cements. Like albumen and caseine, it speedily putrefies if exposed to the air in a moist state, and in decomposing forms products which have a very unpleasant odor.

Flour paste is prepared in precisely the same manner as starch paste, but while the latter is white, flour paste, even if prepared from the best wheat flour, has always a yellow-brown color. As regards adhesive power it is superior to starch paste, but is less durable.

There are many means to prevent the spoiling of paste. With paste once dry and kept so, there is no danger of spoiling, but if it is alternately exposed to dampness and dryness, as for instance with wall-paper hung on walls not entirely dry, decomposition will unavoidably take place, and the wall paper will become spotted and fall off the wall.

Provided either starch or flour paste is protected against drying in, it can be kept unchanged for a long time by the addition of a small quantity of carbolic acid.

For hanging wall-paper an addition of alum is, generally speaking, more suitable than carbolic acid.

In hanging wall-paper the wall is generally first sized with glue water. By the alum coming in contact with glue an insoluble leather-like combination is formed, which not only resists decomposition, but by far surpasses ordinary paste as regards adhesive power, so that when the paper is to be removed from the wall it has to be scraped and torn off in small pieces, while that hung without previous sizing of the wall is readily removed in large pieces.

But alum cannot be used for preserving a glue solution, as it would cause it to coagulate to a flaky mass. Carbolic acid is, on the other hand, an excellent means for the purpose, but to prevent its characteristic empyreumatic odor from making itself too sensibly felt, no more than about one two-thousandth of the weight of the glue solution should be added.

Shoemakers’ paste. In addition to being cheap, no other paste adheres as well to leather as the so-called shoemakers’ paste. With it leather can be secured not only to leather, but also to woven materials, paper, etc. Though its preparation is very simple, it is connected with some disagreeable features consisting chiefly in the development of a truly terrible stench.

The paste is prepared by stirring crushed barley with hot water to a thick paste and adding small portions of hot water, so that the temperature of the mass is kept at between 86° to 104° F. In a few days the mass commences to develop gas, which shows at first no odor, but soon the development of gas becomes stronger and an acid odor is perceptible, which in a short time is replaced by a terrific stench which, as before mentioned, affects the olfactory organs in a most unpleasant manner.

In consequence of the acid and putrid fermentation the pasty mass gradually loses its granular condition, and is finally converted into a homogeneous, thickly fluid mass of a brown color, which draws threads between the fingers, and possesses great adhesive power. When this is the case, decomposition, which otherwise would go on until nothing remained but a watery and acid fluid, is interrupted by lowering the temperature of the paste by ladling it from the vat or by adding a small quantity of carbolic acid.

To render the stench developed during the fermentation of the paste innoxious, the vat in which it is prepared should be provided with a well-fitting cover, in which is fitted a stovepipe passing into a chimney connected with a kitchen range or furnace, in which a fire is frequently burnt.

By kneading shoemaker’s paste together with indifferent substances it can be used as a cement for various purposes. The substances best adapted for the purpose are burnt lime slaked to a powder, whiting, zinc white, pipe clay, ochre, etc.

Gum arabic. This gum is an exudation from certain tropical species of acacia, and consists essentially of arabine, which has the composition C₁₂H₁₁O₁₁. The best gum arabic is that in the form of very pale-yellow, brittle pieces; golden-yellow to brownish pieces are not valued as highly, though they give a solution of considerable adhesive power.

Gum arabic dissolves in water, but not in alcohol, and therefore can not be employed for cements in the preparation of which solutions of resins in spirit of wine are to be used.

There are other products of vegetable life, which are also in commerce, called gums, but dissolve partly in spirit of wine. To this class belongs the gum ammoniac mentioned in some receipts for cements. As it is rather expensive, it is seldom used by itself as a cement.

Dextrine is extensively used in place of gum arabic in printing wall-papers, for stiffening and glazing cards and paper, for thickening the colors of calico printers, in making mucilages, etc. It is prepared by heating starch previously moistened with nitric acid in an oven, and can also be produced by heating paste with malt extract or very dilute sulphuric acid. There is a current anecdote which attributes the discovery of dextrine to a conflagration at a starch factory where one of the workmen who assisted in quenching the fire observed the gummy properties of the water which had been thrown over the torrefied starch.

Commercial dextrine forms pale-yellow to dark-brown masses. These masses dissolve readily in water, and form solutions which, as regards adhesive power, compare favorably with those prepared from gum arabic. The mucilage is prepared by simply stirring the pulverized dextrine with water to a thickly-fluid liquid.

To preserve mucilage unchanged for any length of time, and to prevent the disagreeable formation of mould upon its surface, it is recommended to dissolve some salicylic acid in the water to be used for preparing the mucilage.

Dextrine is usually prepared on a large scale by moistening 10 parts of starch with 3 parts of water acidulated with 1/100 part of nitric acid. The mixture is allowed to dry, and is then spread upon trays in layers about three-quarters of an inch deep in an oven, where it is heated for about one hour to 239° F. Sometimes large drums revolving over a fire are used, or, in order to keep up a uniform temperature, the starch is placed in a copper cylinder suspended in a vessel with oil which is heated to 356° F. The object of the addition of nitric acid is to allow the starch to be converted into dextrine at a temperature which would be inadequate to effect the transformation of starch alone.

Dextrine is also frequently prepared by allowing germinated barley or malt to act upon starch. Heat 350 to 400 parts of water to about 77° F., and after adding 5 to 10 parts of dry malt, raise the temperature to 140° F. Then add 100 parts of starch, and after mixing the whole thoroughly together, raise the temperature to about 158° F. for twenty minutes. The mass, which appears at first milky and sticky, will gradually become as liquid as water by the conversion of the starch into gum through the action of the malt. To prevent the conversion of the gum into sugar by the diastase of the malt, the fluid must be quickly brought to the boiling-point, and, after cooling, filtered and evaporated to the consistency of syrup. In cooling, the mass gelatinizes to a jelly, which after drying is hard and brittle.

According to Blumenthal’s method, a drum which can be hermetically closed, is filled two-thirds full with dry starch flour by means of a funnel. A stirring apparatus is then set in motion, and the acid which is contained in a graduated cylinder is sprayed into the drum by means of a special contrivance.

In a drum 5 feet long and 3¼ feet in diameter, 220 lbs. of potato starch can be uniformly mixed in 5 minutes with about 9 ozs. of nitric acid of 40° B., and the drum emptied by opening the slide. Starch thus treated may be brought into the oven without previous drying.

HeuzÉ gives the following method: Four and a half pounds of nitric acid of 1.4 specific gravity together with 300 quarts of water are mixed with 2,200 lbs. of starch, and boiled to form a mass which, when exposed to the air becomes dry. It is sometimes effected at 177° F., but it becomes a paste at 212° to 230° F. The starch changes into dextrine in an hour or an hour and a half at the most; it is white and soluble in water.

Tragacanth, or gum tragacanth, exudes from Astragalus verus, a tree indigenous to Asia. The term gum is a misnomer, as tragacanth does not actually dissolve in water nor in spirit of wine, but merely swells up in water to a soft gelatinous mass. Tragacanth consists of irregular pieces of a pure white to yellowish color. It is chiefly used for confectioner’s purposes, though sometimes as a paste for fancy articles. This variety of gum is found, together with arabine, in the gum which exudes from cherry, plum, almond, and apricot trees, and gives the mucilaginous character to the watery decoctions prepared from certain seeds, such as linseed and quince-seed, and from the root of marshmallow.

PASTES AND MUCILAGES FOR SPECIAL PURPOSES.

Starch paste. Corn starch 8 ozs., cold water ½ pint, boiling water 1 gallon.

Beat up the starch in the cold water until reduced to a creamy consistence, then pour the mixture into the boiling water and stir briskly until the white, semi-opaque mass, becomes transparent. Should it fail to do so, place it over the fire, and boil until the desired result is obtained, stirring constantly.

Flour paste. Wheat flour 4 lbs., cold water 2 quarts, alum 2 ozs., hot water ½ pint, boiling water 2 gallons.

Work the wheat flour into a batter free from lumps with the cold water. Dissolve the alum in the hot water. Then stir the batter into the boiling water, and if necessary, continue boiling until the paste thickens into a semi-transparent mucilage, after which stir in the alum solution. This makes a very fine paste for wall-paper.

Strong adhesive paste. Rye flour 2 lbs., cold water 1 quart, boiling water 3 quarts, pulverized rosin 1 oz.

Make the flour into a batter with the cold water, free from lumps, and pour into the boiling water. Boil, if necessary, and while hot stir in the pulverized rosin, a little at a time. This paste is very strong, and will fasten heavy wall-paper or thin leather. If too thick, thin with hot water. Never thin paste with cold water.

Paste that will not sour. Allow 4 parts by weight of glue to soften in 15 parts of cold water for some hours, and then heat moderately till the solution becomes quite clear; then add, while stirring, 65 parts of boiling water. In another vessel stir up 30 parts of starch paste with 20 parts of cold water, so that a thin, milky fluid without lumps is obtained. Into this pour the boiling glue solution, stirring constantly, and keep the whole at the boiling temperature. After cooling, add 5 to 10 drops of carbolic acid to the paste. Preserve the paste in closed bottles to prevent evaporation of the water. It will thus keep good for years.

Venetian paste. White or fish glue 4 ozs., cold water ½ pint, Venice turpentine 2 fluid ozs., rye flour 1 lb., cold water 1 pint, boiling water 2 quarts.

Soak the 4 ozs. of glue in the cold water for 4 hours. Dissolve over a water-bath, and while hot stir in the Venice turpentine. Make up the rye flour into a batter free from lumps with the pint of water, and pour the latter into the boiling water. Stir briskly, and finally add the glue solution. This makes a very strong paste, and it will adhere to a painted surface, owing to the Venice turpentine in its composition.

Label paste. A good paste for attaching labels to bottles may be made by soaking glue in strong vinegar, then heat to boiling and add flour. This is very adhesive, and will not decompose when kept in wide-mouthed bottles.

Elastic or pliable paste. Starch 4 ozs., white dextrine 2 ozs., cold water 10 fluid ozs., borax 1 oz., glycerine 3 fluid ozs., boiling water 2 quarts.

Beat the starch and dextrine into paste with the cold water. Dissolve the borax in the boiling water, then add the glycerine, and pour the starch and dextrine mixture into the borax solution. Stir until it becomes translucent. This paste will not crack, and, being very pliable, is suitable for paper, cloth, leather and other material where flexibility is required.

Mucilage for labels. Macerate 5 parts of good glue in 20 parts of water for 24 hours, and to the liquid add 9 parts of rock candy, and 3 parts of gum arabic. The mixture may be brushed upon paper while lukewarm. It keeps well, does not stick together and adheres firmly to bottles.

Mucilage. A strong aqueous solution of dextrine forms a most adhesive and cheap mucilage. Dilute alcohol is usually employed as the solvent where the mucilage is to be used for gumming envelopes, postage stamps, etc., and in order to facilitate the drying, acetic acid is added to increase the mobility of the fluid. The strong aqueous solution is more adhesive than that prepared with alcohol, for the reason that it contains a greater proportion of dextrine.

To prepare this add an excess of dextrine to boiling water, stir for a minute or two, allow to cool and settle, and strain the liquid through a cloth. The addition of a little powdered sugar increases the glossiness of the dried gum. The sugar should be dissolved in the water before the dextrine is added.

According to another formula, dextrine is mixed with hot water until a syrupy liquid is obtained. Then add a few drops of oil of cloves, and cool for use.

Another formula is as follows: Dextrine 120 parts, powdered alum 6, sugar 30, carbolic acid 1, water 300. Mix gradually the dextrine, alum and sugar with the water, boil to effect solution, and when cold, add the carbolic acid.

The solubility of dextrine may be enhanced by the addition of a calcium salt readily soluble in water, the resulting mixture dissolving with ease in cold water. Calcium nitrate has proved especially suitable for the purpose. By pouring 1 quart of water over a mixture of 18 ozs. of dextrine and 7 ozs. of calcium nitrate, a mass of great adhesive power is immediately obtained.

Mucilage for postage stamps. Dextrine 2 parts, acetic acid 1, water 5, alcohol 1. Mix all together.

Caseine mucilage. Take the curd of skim milk, wash it thoroughly, and dissolve it to saturation in a cold concentrated solution of borax.

Tragacanth mucilage. Powdered tragacanth 2 drachms, glycerine 12 drachms, water enough to make 20 ozs.

Put the tragacanth in a mortar with the glycerine, and then add the water. This will produce at once a mucilage of excellent quality.

Adhesive paste. Steep 4 ozs. of ordinary gelatine in 16 ozs. of water until it becomes soft, then dissolve it by the heat of a water bath, and while still hot pour into a mixture of 2 lbs. of good flour paste and 1 part of water. Heat the whole to boiling and when thickened remove from the fire. While cooling add 6 drachms of silicate of soda and stir the mixture with a wooden spatula. This preparation will keep good for an indefinite period, and is very adhesive. The addition of 2 drachms of oil of cloves is an improvement.

Fluid pastes. I. Gum arabic 10 lbs., sugar 2 lbs., nitric acid 1¾ ozs., water as required.

Dissolve the gum and sugar in the water, then add the acid and heat to the boiling-point. The resulting paste is liquid, does not mould, and dries to a transparent layer upon paper. It is especially suitable for flaps of envelopes, fine bookbinders’ work, etc.

II. Potato starch 10 lbs., water 5 quarts, nitric acid 8 ozs.

Mix the acid and water and pour it on the starch in an earthenware basin, put the latter in a warm place, and allow it to remain 24 hours, with occasional stirring. Then boil it until it becomes thickly-fluid and very transparent. If necessary it should be diluted with water and filtered through a cloth.

Sugar and lime paste. Dissolve 12 parts of white sugar in 36 of water. Heat the solution to the boiling-point and add 3 parts of slaked lime. Allow the liquid to stand in a covered vessel for several days, stirring frequently and, when settled, pour off the supernatant thick fluid from the excess of lime.

The paste thus obtained has all the properties of gum arabic solution and dries to a lustrous mass.

Liquid sugar and lime paste. Allow 3 parts of glue to swell in 10 to 15 parts of the foregoing paste. Heat the mixture to the boiling-point. The paste thus obtained does not congeal on cooling and possesses considerable adhesive power.

By reason of its caustic properties, due to the content of lime, this paste should not be used for pasting colored materials.

Pastes for paper and fine fancy articles. I. Dissolve, with the assistance of heat, 100 parts of gilder’s glue in 200 of water, and add a solution of 2 parts of bleached shellac in 10 of alcohol.

II. Dissolve, with the assistance of heat, 50 parts of dextrine in 50 of water, stir solutions 1 and 2 together, strain through a cloth into a flat prismatic mould, and allow it to congeal. For use, melt a piece of corresponding size, and dilute the liquid, if necessary, with water.

Albumen paste. This is a misnomer, as it contains no albumen. It is partly decayed gluten from flour, washed with water and then heated to 60° or 68° F., when it ferments and becomes partly fluid. It is then dried at 77° to 86° F., and is claimed to keep any length of time in a dry place. Dissolved in twice its weight of water it can be used as a paste for all purposes.

Glycerine paste. Dissolve 2 ozs. of gum arabic and 4 drachms of glycerine in 6 ozs. of boiling water. This is a good paste for office use.

Paste for fixing labels on machines. Make a paste of rye flour and glue and add to every pound thereof ½ oz. each of boiled linseed oil and turpentine. This paste resists damp and thus prevents printed labels from falling off metallic surfaces.

Paste for mounting maps. Stiff rye flour paste is best for this purpose.

Paste for fastening paper on tin-foil. Make a paste by dissolving rye flour in solution of caustic soda; dilute with water, stirring all the time. Add to this paste a few drops of Venice turpentine for each ½ lb. of flour.

Paste for paper bags. Add to 3 parts of starch 24 to 30 parts of cold water. Stir together to a homogeneous mass of about the thickness of syrup. Pour over this, stirring constantly, boiling water until the paste is of the required consistency. Stir until nearly cold. Take a portion of the paste and add to it 6 to 15 per cent. liquefied Venice turpentine; rub together until a kind of emulsion is formed, then mix the whole together and work thoroughly.

Caseine mucilage for photographer’s use. Separate the caseine from milk by means of a little tartaric acid, and treat the caseine while still warm with a solution of 6 parts of borax to 100 parts water, and warm gently while stirring which will cause the caseine to be dissolved. Of the borax solution enough should be used to leave only a little undissolved caseine behind.

Paste for scrap-books. Rice starch 1 oz., gelatine 3 drachms, water ½ pint.

Heat, stirring constantly, until the milky fluid becomes thick and gluey. When the paste is nearly thick put in a bottle closely corked. It is well to add a few drops of oil of cloves to each bottle.

Paste for skins. Pour enough boiling water over 1 lb. of rye flour in a basin to make a stiff paste, almost as stiff as ordinary dough for puddings. Stir and beat up well with a stick for three or four minutes, then cover up and let it stand for two days before using, when it will be much softer and stick better. Spread thinly and evenly on the back of the skin with a stiff brush or pad. It will stick firmly and not crack.

Strong mucilage capable of fastening wood or china and glass together is made of 3½ ozs. of strong gum arabic solution, to which a solution of 30 grains of sulphate of aluminium dissolved in ? oz. of water is added.

Dextrine mucilage. I. Dissolve with the assistance of heat 60 parts of borax in 420 parts of water, add 480 parts of pale yellow dextrine and 50 parts of glucose, and heat carefully, stirring constantly until solution is complete, replacing the water lost by evaporation. Strain through flannel.

The resulting mucilage is quite clear, has great adhesive power, and dries very quickly. In heating the mixture, great care should be exercised not to exceed a temperature of 194° F. and not to heat too long, otherwise the product readily becomes brown and brittle.

II. Dextrine 120 parts, powdered alum 6, sugar 30, carbolic acid 1, distilled water 300. Gradually mix the dextrine, alum and sugar with the water, effect solution by boiling and when the solution is cold, add the carbolic acid.

Paste for joining leather to pasteboard. Dissolve 50 parts of strong glue with a little water at a gentle heat, then add a small quantity of Venice turpentine, and next a thick paste made with 100 parts of starch in water. Apply quickly when cold.

Another formula for a similar paste is as follows: Rye whisky 2 pints, water 1 pint, powdered starch 4¼ ozs., good glue 1¼ ozs., Venice turpentine 1¼ ozs. Mix the whisky and water together, then stir in the starch and make a thick paste. Separately dissolve the glue in an equal weight of water, and mix the Venice turpentine therein, mix thoroughly, and then compound this mixture with the thick paste by constantly stirring until all is well incorporated.

Paste for attaching labels to polished nickel. Dissolve 400 parts by weight of dextrine in 600 parts of water, and add 20 parts of glycerine and 10 parts of glucose. Heat the mixture to 194° F.

Another formula is as follows: Mix 400 parts by weight of dextrine with water, and add 200 parts of water together with 20 parts of glucose and 10 parts of aluminium sulphate.

Mucilage for attaching labels to tin. I. Shellac 8 parts, borax 4 parts, water 60 parts. Boil until the shellac is dissolved.

II. To 2 parts of dammar varnish add 8 parts of tragacanth mucilage.

III. An excellent mucilage for the purpose consists of starch paste to which a small quantity of Venice turpentine has been added.

IV. Make a paste of corrosive sublimate 2½ parts, wheat flour 200, absinthe 100, tansy 50, water 3000. This mucilage is useful for vessels kept in a damp place.

Mucilage for office use. Gum arabic 100 parts, aluminium sulphate 6 parts, glycerine 10, dilute acetic acid 20, distilled water 140. Dissolve, in a wide-mouthed glass bottle, the gum arabic in cold distilled water, stirring frequently. Let the solution stand 2 or 3 days, then add the glycerine, later on the dilute acetic acid and finally the aluminium sulphate. Strain through a hair sieve, allow to clarify, and decant from the sediment.

Glycerine paste for office use. Dissolve 4 ozs. of gum arabic and 8 drachms of glycerine in 12 ozs. of boiling water.

Clean and durable paste. Dissolve 5 ozs. of gum arabic in 4 quarts of warm water, and thicken to a paste with wheat flour. Then add a solution of alum and sugar of lead, 3 ozs. of each in water. Heat the mixture and stir it until it is about to boil, and then cool it. If too thick, add gum solution.

Banknote or mouth glue. Dissolve by the aid of heat a fine quality of glue or gelatine with about a quarter or one-third of its weight of brown sugar, in as small a quantity of water as possible. Then when perfectly liquid cast the mixture into thin cakes on a flat surface very slightly oiled, and when cold cut up into pieces of convenient size. When required for use moisten one end. A piece of this glue kept in the desk will be found very convenient for many purposes.

Paste for cardboard. Dissolve 3½ ozs. of best French glue in 6½ ozs. of water by soaking and heating. Then add a solution of ½ drachm of shellac in 3½ drachms of alcohol and stir as long as the solution is warm. Next dissolve 2 drachms of dextrine in 1¾ ozs. of alcohol and 14 drachms of water, stir, and place the vessel in warm water until solution is complete. Mix this solution with that of the glue, and pour the whole into a suitable vessel, in which it may solidify. When wanted for use cut off a small piece and liquefy it by warming.

Paste for attaching cloth or leather to table tops. Wheat flour 1 lb., powdered rosin 2 tablespoonfuls, powdered alum 1 tablespoonful. Heat and stir to a stiff consistency.

Caseine mucilage. Separate the caseine from milk with a little tartaric acid, and treat the caseine while still warm with a solution of 6 parts borax to 100 parts water and warm gently while stirring, which will cause the caseine to be dissolved. Of the borax solution enough should be used to leave only a little undissolved caseine behind.

Very adhesive paste which may be used for wood and parchment. Gum arabic 60 parts, fine wheat starch 45, sugar 15. Dissolve the gum in as much water as is required for boiling the quantity of paste to be made. Then add the starch and sugar and boil it in a vessel suspended in boiling water until the mixture is clear and has the consistency of liquid tar. Keep in a well-closed vessel protected from mould by the addition of a few drops of oil of cloves.

Paste for pads. Glue 4 parts by weight, glycerine 2, linseed oil ½, sugar 4, aniline dye sufficient to color. Soften the glue by soaking in cold water, then dissolve together with the sugar in the glycerine by the aid of heat over the water-bath, then add the dye and stir in the oil. Use the paste hot.

Paste for fastening paper on tin-foil. Make a paste by dissolving rye flour in a solution of caustic soda; dilute with water, stirring constantly. Add to this paste a few drops of Venice turpentine for each ½ lb. flour used. This paste adheres to all kinds of metal, tin-foil, glass, etc.

Paste for attaching labels to glass, porcelain, and metal. Gum arabic 15 parts, pulverized tragacanth 7½, glycerin 45, thymol 0.3, alcohol 3¾, water 120. Dissolve the gum arabic in 15 parts of water and triturate the tragacanth with 30 parts of water. Mix the two fluids and strain. Then add the glycerine and finally the thymol dissolved in the alcohol.

Preparation of arabol-gum. Mix intimately 44 lbs. of wheat starch with 176 lbs. of water. Bring the mass into a water-bath, mix it with a solution of 4.4 lbs. of oxalic acid in 44 lbs. of water and heat for four hours at 194° F., stirring frequently. The conversion of the starch is as a rule effected during this time, but should such not be the case, continue heating, constantly replacing the evaporated water, until the mass is clear and liquid. While still hot, neutralize the mass with marble dust, allow to settle, filter, and evaporate the clear solution in a water-bath to a solid gum containing about 15 per cent. of water.

Preparation of an adhesive substance from desaccharized beet-root slices (German patent 96316 f. G. Eichelbaum). The insoluble metarabin contained in the slices is converted into soluble arabin by treating the slices under pressure with hot aqueous sulphurous acid or with aqueous solutions of the bisulphites of the alkalies or alkaline earths.

According to a later patent (German patent 121422 f. Fabrik Bettenhausen Marquart and Schulz), the insoluble metarabin is converted into soluble arabin by heating the desaccharized beet-root slices with phosphoric acid and water. According to a supplement to this patent (122048), conversion is effected by heating the slices with aqueous solutions of organic acids and phenols, or the acid salts of oxalic, tartaric or phosphoric acids.