Chapter XIII (1)

PREPARATION OF CEMENTS, PASTES, AND MUCILAGES.

OIL CEMENTS.

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 ⅛ 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.