Rensselaer Republican, Volume 12, Number 25, Rensselaer, Jasper County, 5 March 1880 — ABOUT CEMENTS. [ARTICLE]

ABOUT CEMENTS.

Quite as much depends upon the manner in which a cement is used as upon the cement itself. The best cement that ever was compounded would prove entirely worthless if improperly applied. The following rules, must be rigorously adhered to u success would be secured: ' 1. Bring the cement into intimate oontact with the surfaces to be united. This is best done by heating the pieces to be joined in those cases where the cement is melted by heat, as in using resin, shellac, marine glue, etc. Where solutions are used the cement must be well rubbed into the surfaces, either with a soft brush (as in the case of porcelain or glass), or by rubbing the two surfaces together (as in making a glue joint between two pieces of wood). 2. As little oement as possible should be allowed to remain between the united surfaces. To secure this the cement should be as liquid as possible (thoroughly melted if used with heat), and the surfaces should be pressed closely into contact (by screws, weights, wedges or oords) until the cement has hardened.

8. Plenty of time should be allowed for the cement to dry or harden, and this is particularly the case in oil cements, such as copal varnish, boiled oil, white lead, etc. When two surfaces, each half an inch across, are joined by means of a layer of white lead placed between them, six months may elapse before the cement in the middle of the joint has become hard. In such cases a few days or weeks are of no account; at the end of a month the joint will be weak and easily separated, while at the end of two or three years it may be so firm that the material will part anywhere else than at the joint. Hence when the article is to be used immediately, the only safe cements are those which are liquefied by heat, and which become hard when cold. A joint made with marine glue is firm an hour after it has been made. Next to cements that are liquefied by heat are those which consist of substances dissolved in water or alcohol. A glue joint sets firmly in twenty-four hours; a joint made with shellac varnish becomes dry in two or three days. Oil cements, which do not dry by evaporation, but harden by oxidation (boiled oil, white lead, red lead, etc., etc.) are the slowest of all. Aquarium Cement, —Litharge, fine, white, dry sand, and plaster of Paris, each one gill; finely pulverized resin, 1-3 gill. Mix thoroughly and make into a paste with boiled linseed oil to which drier has been added. Beat it well, and let it stand four or five hours befoie using it. After it has stood for fifteen hours, however, it loses its strength. Glass cemented into its frame with this cement is good for either salt or fresh water. It has been used at the Zoological Gardens, London, with great success. It might be useful for constructing tanks for other purposes, or for stopping leaks. Casein Mucilage. —Take the curd of skim milk (carefully freed from cream or oil), wash it thoroughly, and dissolve it to saturation in a cold concentrated solution of borax. This mucilage keeps well, and as regards adhesive power far surpasses the mucilage of gum arabic. Casein and Soluble Glass. —Casein dissolved in soluble silicate of soda or potassa makes a very strong cement for glass or porcelain. Cheese Cement for Mending China , etc. —-Take; skim milk cheese, cut it in slices and boil it in water. Wash it in cold water and knead it in warm water several times. Place it warm on a levigating stone and knead it with quicklime. It will join marble, stone, or earthenware so that the joining is scarcely to be discovered. Chinese Cement ( Schic-liao') . —Tothree parts of fresh beaten blood are added four parts of slaked lime and a little alum; a thin, pasty mass is produced, which can be used immediately. Objects which are to be made specially waterproof are painted by the Chinese twice, or at the most three times. Dr. Scherzer saw in Pekin a wooden box which had traveled the tedidhs road via Siberia to St. Petersburg and back, which was found to be perfectly sound and water-proof. Even baskets made of straw become, by the use of this cement, perfectly serviceable in the transportation of oil. Pasteboard treated therewith receives the appearance and strength of wood. Most of the wooden public buildings of China are painted with schio-liao, which gives unpleasant reddish appearance, butaddsto their durability. Tnis cement was tried in the Austrian Department of Agriculture, and by the “ Vienna Association of Industry,” and in both cases the statements of Dr. Scherzer were found to be strictly accurate. Faraday's Cap Cement. —Electrical Cement.—Resin, five oz.; beeswax one oz.; red ocher or Venetian red in powder, one oz. Dry the earth thoroughly on a stove at a temperature above 212 degrees. Melt the wax and resin together and stir in the powder by degrees. Stir until cold, lest the earthy matter settle to the bottom. Used for fastening brass work to glass tubes, flasks: etc

Cement for Class, Earthenware , etc. — Dilute white of egg with its bulk of water and beat up thoroughly. Mix to the consistence of thin paste with powdered quicklime. Must be used immediately. Class Cement. —Take pulverized glass, ten parts; powdered fluorspar, twenty parts; soluble silicate of soda, sixty parts. Both glass and fluorspar must be in the finest possible condition, which is best done by shaking each in fine powder, with water, allowing the ooarserparticles to deposit, and then to pour off the remainder, which holds the finest particles in suspension. The mixture must be made very rapidly, by qriek stirring, and when thoroughly

mixed roust be at ouoe applied. This is said to yield an excellent oement. Gutia tcrcha Cement —This highly recommended oement is made by melting together, in an iron pan, two parts common pitch and one part gutta percha, stirring them well together tmtil thoroughly incorporated, and then pouring the liquid into cold water. When oold it is black, solid and elastic; but it softens with heat, and at 100 degrees Fahrenheit is a thin fluid. It may be used as a soft paste, or in the liquid state, and answers an excellent purpose in cementing metal, glass, porcelain, ivory, etc. It may be used instead of putty for glazing windows. Iron Cement for Closing the Joints of Iron Pipes.—Take of coarsely-powdered iron borings 6 pounds; powdered salammoniac, 2 ounces; sulphur, 1 ounce; and water sufficient to moisten it. 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. * 2. Take sal-ammoniac, 2 ounces; sublimed sulphur, 1 ounce; oast-iron filings or fine turnings, 1 pound. Mix in a mortar and keep the powder dry. When it is to be used, mix it with twenty 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 consistenoe, when it is be applied to the joint. After a time it becomes as hard and strong as any part of jthe metal. • Kerosene Oil Lamps.— The cement commonly used for fastening the tops on kerosene lamps is plaster of Pans, which is porous and quickly penetrated by the kerosene. Another oement which has not this defect is mine with three parts of resin, one of caustic soda and five of water. This composition is mixed with half its weight of plaster of Paris. It sets firmly in about three quarters of an hour. It. is said to be of great adhesive power, not permeable to kerosene, a low conductor of heat, and but superficially attacked byJiot water. - v

Cement for Uniting Leather and Aletai. —Wash the metal with hot gelatine; steep the leather in an infusion of nut galls (hot) and bring the two together Cement for Leather Belting.— One who has tried everything says that after an experience of fifteen yearshe has found nothing to equal the following: Common glue and isinglass, equal parts, soaked for 10 hours in just enough water to cover them. Bring gradually to a boiling heat and add pure .tannin until the whole becomes ropy or appears like the white of eggs. Buff off the surfaces to be joined, apply this cement warm, and clamp firmly. • - Litharge and Glycerine Cement. — A cement made of very finely-powdered oxide of lead (litharge) ana concentrated glycerine unites wood to iron with remarkable efficiency. The composition is insoluble in most acids, is unaffected by the action of moderate heat, sets rapidly, and acquires an extraordinary hardness. Cement for Attaching Metal to Glass. — Copal varnish, 16; drying oil, five; turpentine, three. Melt in a water-bath an 1 add 10 parts slaked lime. Paris Cement for Mending Shells and other Specimens. —Gum arabic. five; sugar candy, two; white lead, enough to color. Porcelain Cement. —Add plaster of Paris to a strong solution of alum till the mixture is of the consistency of cream. It sets readily, and is said to unite glass, metal, porcelain, etc., quite firmly. It is probably suited for cases in which large rather than small surfaces are to be united. ' Soft Cement. —Melt yellow beeswax with its weight of turpentine, and color with finely-powdered Venetian red. When cold it has the hardness of soap, but is easily softened and moulded with the fingers, and for sticking things together temporarily it is invaluable. Soluble Glass Cements.— When finely , pulverized chalk is stirred into a solution of soluble glass 80 deg’s B. until the mixture is fine and plastic, a cement’is obtained which will harden in between six and eight hours, possessing an extraordinary durability, and alike applicable for domestic and industrial purposes. If any of the following substances be employed besides chalk, dif-ferently-colored cements of the same general character are obtained: 1. finely pulverized or levigated stibnite (gray antimony, or black sulphide of antimony) will produce a dark cement, which, after long burnishing with an agate, will present a metallic appearance. 2. Pulverized cast iron, a gray cement. 3. Zinc dust (so-called zinc gray), an exceedingly hard gray cement, which, after burnishing, will exhibit the white and brilliant appearance of metallic zinc. This cement may be employed with' advantage in mending ornaments and vessels of zinc, sticking alike well to metals, stone and wood. 4. Carbonate of copper, a bright green cement! 6. Sesquioxide of chromium, a dark green cement. 6. Thenad’s blue (cobalt blue), a blue cement. 7. Minium, an orange-colored cement. 8. Vermilion, a splendid red cement. 9. Carbon red, a violet cement. BoreTs Cement.—MJ/x commercial sine white with half its bulk of fine sand, adding a solution of chloride of zinc of 1.26 specific gravity, and rub the whole thoroughly together in a mortar. The mixture must De applied at once, as it hardens very quickly. if! Steam Bouer Cement.— Mix two parts of finely-powdered litharge with one part of very fine sand, aj»a one part of quickJme which has been allowed to slake spontaneously by exposure to the air. This mixture may be kept for any length of time without injuring. In using it a portion is mixed into paste with linseed oil, or, still better, boiled linseed oil. In this state it must be quickly applied, as it soon becomes hard.; Turner’s Cement. —Melt one pound of resin in a pan over the fire, and, when melted, add one-quarter of a pound of pitch. While these are boiling add brick dust until, by droppinganttle on a cold stone, you think it hard enough. In winter it may be necessary to add a little tallow. By means of this cement a piece of wood may be fastened to the chuck, which will bold when cool; and when the work is finished it may be removed by a smart stroke with the tooL Any traces of the oement may be removed from the work by means of benzine. Wollaston's White Cement for Large Objects. —Beeswax, one ounoe; resin, four ounces; powdered plaster of Paris, five ounces. Melt together. To use, warm the edges of the specimen and use the oement warm.— Druggist's Circular.

The trouble about the Gear has at last come out. Dispatches ‘ show that the mine was laid by workmen who were sent to fix the gas pipes under the dining-room. In other words, Alexaf. der was the latest victim of the omnipresent plumbers* —petroit fret ft*#.