Part 125

In all these powders the gums are first to be thoroughly triturated and mixed by passing through a sieve, and the other ingredients carefully added. Other colors may be made by using chrome yellow, burnt or raw sienna, raw or burnt umber, Vandyke brown, etc. For stamping fabrics liable to be injured by heat, the stamping is done by moistening a suitable powder with alcohol and using it like a stencil ink.

«Stamping Powder for Embroideries.»—“Stamping powders” used for outlining embroidery patterns are made by mixing a little finely powdered rosin with a suitable pigment. After dusting the powder through the perforated pattern it is fixed on the fabric by laying over it a piece of paper and then passing a hot iron carefully over the paper. By this means the rosin is melted and the mixture adheres. When white goods are to be “stamped,” ultramarine is commonly used as the pigment; for dark goods, zinc white may be substituted. Especial care should be taken to avoid lead compounds and other poisonous pigments, as they may do mischief by dusting off. On velvets or other materials likely to be injured by heat, stamping is said to be done by moistening a suitable powder with alcohol and using it as stencil paint. A small addition of rosinous matter would seem required here also.

«Starch»

«Black Starch.»—Add to the starch a certain amount of logwood extract before the starch mixture is boiled. The quantity varies according to the depth of the black and the amount of starch. A small quantity of potassium bichromate dissolved in hot water is used to bring out the proper shade of black. In place of bichromate, black iron liquor may be used. This comes ready prepared.

«Starch Gloss.»—I.—Melt 2 1⁠/⁠2 pounds of the best paraffine wax over a slow fire. When liquefied remove from the fire to stir in 100 drops of oil of citronella. Place several new pie tins on a level table, coat them slightly with sweet oil, and pour about 6 tablespoonfuls of the melted paraffine wax into each tin. The pan may be floated in water sufficiently to permit the mixture to be cut or stamped out with a tin cutter into small cakes about the size of a peppermint lozenge. Two of these cakes added to each pint of starch will cause the smoothing iron to impart the finest possible finish to muslin or linen, besides perfuming the clothes.

II.—Gum arabic, powdered 3 parts Spermaceti wax 6 parts Borax, powdered 4 parts White cornstarch 8 parts

All these are to be intimately mixed in the powder form by sifting through a sieve several times. As the wax is in a solid form and does not readily become reduced to powder by pounding in a mortar, the best method of reducing it to such a condition is to put the wax into a bottle with some sulphuric or rectified ether and then allow the fluid to evaporate. After it has dissolved the wax, as the evaporation proceeds, the wax will be deposited again in the solid form, but in fine thin flakes, which will easily break down to a powder form when rubbed up with the other ingredients in a cold mortar. Pack in paper or in cardboard boxes. To use, 4 teaspoonfuls per pound of dry starch are to be added to all dry starch, and then the starch made in the usual way as boiled starch.

«Refining of Potato Starch.»—A suitable quantity of chloride of lime, fluctuating according to its quality between 1⁠/⁠2 to 1 part per 100 parts of starch, is made with little water into a thick paste. To this paste add gradually with constant stirring 10 to 15 times the quantity of water, and filter.

The filtrate is now added to the starch stirred up with water; 1⁠/⁠2 part of ordinary {681} hydrochloric acid of 20° Bé. previously diluted with four times the quantity of water is mixed in, for every part of chloride of lime, the whole is stirred thoroughly, and the starch allowed to stand.

When the starch has settled, the supernatant water is let off and the starch is washed with fresh water until all odor of chlorine has entirely disappeared. The starch now obtained is the resulting final product.

If the starch thus treated is to be worked up into dextrin, it is treated in the usual manner with hydrochloric acid or nitric acid and will then furnish a dextrin perfectly free from taste and smell.

In case the starch is to be turned into “soluble” starch proceed as usual, in a similar manner as in the production of dextrin, with the single difference that the starch treated with hydrochloric or nitric acid remains exposed to a temperature of 212° F., only until a test with tincture of iodine gives a bluish-violet reaction. The soluble starch thus produced, which is clearly soluble in boiling water, is odorless and tasteless.

«Starch Powder.»—Finely powdered starch is a very desirable absorbent, according to Snively, who says that for toilet preparations it is usually scented by a little otto or sachet powder. Frangipanin powder, used in the proportion of 1 part to 30 of the starch, he adds, gives a satisfactory odor.

STARCHES: See Laundry Preparations.

STARCH IN JELLY, TESTS FOR: See Foods.

STARCH PASTE: See Adhesives.

STATUE CLEANING: See Cleaning Preparations and Methods.

STATUETTES, CLEANING OF: See Plaster.

STATUETTES OF LIPOWITZ METAL: See Alloys.

«Steel»

(See also Iron and Metals.)

«ANNEALING STEEL:»

See also Hardening Steel and Tempering Steel.

This work requires the use of substances which yield their carbon readily and quickly to the tools on contact at a high temperature. Experience has shown that the best results are obtained by the use of yellow blood-lye salt (yellow prussiate of potash), which, when brought in contact with the tool at a cherry-red heat, becomes fluid, and in this condition has a strong cementing effect. The annealing process is as follows: The tool is heated to a cherry red and the blood-lye salt sprinkled over the surface which is to be annealed. A fine sieve should be used, to secure an even distribution of the substance. The tool is then put back into the fire, heated to the proper temperature for tempering, and tempered. If it is desired to give a higher or more thorough tempering to iron or soft steel, the annealing process is repeated 2 or 3 times. The surface of the tool must, of course, be entirely free from scale. Small tools to which it is desired to impart a considerable degree of hardness by annealing with blood-lye salt are tempered as follows: Blood-lye salt is melted in an iron vessel over a moderate fire, and the tool, heated to a brown-red heat, placed in the melted salt, where it is allowed to remain for about 15 minutes. It is then heated to the hardening temperature and hardened. A similar but milder effect is produced in small, thin tools by making them repeatedly red hot, immersing them slowly in oil or grease, reheating them, and finally tempering them in water. To increase the effect, soot or powdered charcoal is added to the oil or grease (train oil) till a thick paste is formed, into which the red-hot tool is plunged. By this means the tool is covered with a thick, not very combustible, coating, which produces a powerful cementation at the next heating. By mixing flour, yellow blood-lye salt, saltpeter, horn shavings, or ground hoofs, grease, and wax, a paste is formed which serves the same purpose. A choice may be made of any of the preparations sold as a “hardening paste”; they are all more or less of the same composition. This is a sample: Melt 500 grains of wax, 500 grains tallow, 100 grains rosin, add a mixture of leather-coal, horn shavings, and ground hoofs in equal parts till a paste is formed, then add 10 grains saltpeter and 50 to 100 grains powdered yellow blood-lye salt, and stir well. The tools are put into this paste while red hot, allowed to cool in it, then reheated and tempered.

More steel is injured, and sometimes spoiled, by over-annealing than in any other way. Steel heated too hot in annealing will shrink badly when being hardened; besides, it takes the life out of it. It should never be heated above a {682} low cherry red, and it should be a lower heat than it is when being hardened. It should be heated slowly and given a uniform heat all over and through the piece.

This is difficult to do in long bars and in an ordinary furnace. The best way to heat a piece of steel, either for annealing or hardening, is in red-hot, pure lead. By this method it is done uniformly, and one can see the color all the time. Some heating for annealing is done in this way: Simply cover up the piece in sawdust, and let it cool there, and good results will be obtained.

Good screw threads cannot be cut in steel that is too soft. Soft annealing produces a much greater shrinkage and spoils the lead of the thread.

This mixture protects the appearance of polished or matted steel objects on heating to redness: Mix 1 part of white soap, 6 parts of chemically pure boracic acid, and 4 parts of phosphate of soda, after pulverizing, and make with water into a paste. For use, apply this to the article before the annealing.

«COLORING STEEL:»

«Black.»—I.—Oil or wax may be employed on hard steel tools; with both methods the tool loses more or less of its hardness and the blacking process therefore is suited only for tools which are used for working wood or at least need not be very hard, at any rate not for tools which are employed for working steel or cast iron. The handsomest glossy black color is obtained by first polishing the tool neatly again after it as been hardened in water, next causing it to assume on a grate or a hot plate the necessary tempering color, yellow, violet blue, etc., then dipping it in molten, not too hot, yellow wax and burning off the adhering wax, after withdrawal, at a fire, without, however, further heating the tool. Finally dip the tool again into the wax and repeat the burning off at the flame until the shade is a nice lustrous black, whereupon the tool may be cooled off in water. The wax is supposed to impart greater toughness to the tool. It is advisable for all tools to have a trough of fat ready, which has been heated to the necessary tempering degree, and the tools after hardening in water are suspended in the fat until they have acquired the temperature of the fat bath. When the parts are taken out and slowly allowed to cool, they will be a nice, but not lustrous, black.

II.—The following has been suggested for either steel or iron:

Bismuth chloride 1 part Mercury bichloride 2 parts Copper chloride 1 part Hydrochloric acid 6 parts Alcohol 5 parts Water sufficient to make 64 parts.

Mix. As in all such processes a great deal depends upon having the article to be treated absolutely clean and free from grease. Unless this is the case uniform results are impossible. The liquid may be applied with a swab, or a brush, but if the object is small enough to dip into the liquid better results may thus be obtained than in any other way. The covering thus put on is said to be very lasting, and a sure protection against oxidation.

«Blue.»—I.—Heat an iron bar to redness and lay it on a receptacle filled with water. On this bar place the objects to be blued, with the polished side up. As soon as the article has acquired the desired color cause it to fall quickly into the water. The pieces to be blued must always previously be polished with pumice stone or fine emery.

II.—For screws: Take an old watch barrel and drill as many holes into the head of it as the number of screws to be blued. Fill it about one-fourth full of brass or iron filings, put in the head, and then fit a wire long enough to bend over for a handle, into the arbor holes—head of the barrel upward. Brighten the heads of the screws, set them, point downward, into the holes already drilled, and expose the bottom of the barrel to the lamp, until the screws assume the color you wish.

III.—To blue gun-barrels, etc., dissolve 2 parts of crystallized chloride of iron; 2 parts solid chloride of antimony; 1 part gallic acid in 4 or 5 parts of water; apply with a small sponge, and let dry in the air. Repeat this two or three times, then wash with water, and dry. Rub with boiled linseed oil to deepen the shade. Repeat this until satisfied with the result.

IV.—The bluing of gun barrels is effected by heating evenly in a muffle until the desired blue color is raised, the barrel being first made clean and bright with emery cloth, leaving no marks of grease or dirt upon the metal when the bluing takes place, and then allow to cool in the air. It requires considerable experience to obtain an even clear blue.

«Brown.»—I.—The following recipe for browning is from the United States Ordnance Manual: Spirits of wine, 1 1⁠/⁠2 {683} ounces; tincture of iron, 1 1⁠/⁠2 ounces; corrosive sublimate, 1 1⁠/⁠2 ounces; sweet spirits of niter, 1 1⁠/⁠2 ounces; blue vitriol, 1 ounce; nitric acid, 3⁠/⁠4 ounce. Mix and dissolve in 1 quart of warm water and keep in a glass jar. Clean the barrel well with caustic soda water to remove grease or oil. Then clean the surface of all stains and marks with emery paper or cloth, so as to produce an even, bright surface for the acid to act upon, and one without finger marks. Stop the bore and vent with wooden plugs. Then apply the mixture to every part with a sponge or rag, and expose to the air for 24 hours, when the loose rust should be rubbed off with a steel scratch brush. Use the mixture and the scratch brush twice, and more if necessary, and finally wash in boiling water, dry quickly, and wipe with linseed oil or varnish with shellac.

II.—Apply four coats of the following solution, allowing each several hours to dry. Brush after each coat if necessary. After the last coat is dry, rub down hard.

Sulphate of copper 1 ounce Sweet spirits of niter 1 ounce Distilled water 1 pint

«Niello.»—This is a brightly polished metal, which is provided with a black or blue-black foundation by heating, is covered with a design by the use of a suitable matrix and then treated with hydrochloric acid in such a manner that only the black ground is attacked, the metal underneath remaining untouched. Next, the acid is rinsed off and the reserve is removed with suitable solvents. The parts of the metal bared by the acid may also be provided with a galvanic coating of silver or other metal.

Another method is to plunge the articles for a few minutes into a solution of oxalic acid and to clean them by passing them through alcohol. In this way the polish can even be brought back without the use of rouge or diamantine.

«Whitening or Blanching.»—If dissatisfied with the color acquired in tempering, dip the article into an acid bath, which whitens it, after which the bluing operation is repeated. This method is of great service, but it is important to remember always thoroughly to wash after the use of acid and then allow the object to remain for a few minutes in alcohol. Sulphuric acid does not whiten well, often leaving dark shades on the surface. Hydrochloric acid gives better results. Small pieces of steel are also whitened with a piece of pith moistened with dilute sulphuric acid, else the fine steel work, such as a watch hand, is fixed with lacquer on a plate and whitened by means of pith and polishing rouge, or a small stiff brush is charged with the same material. It is then detached by heating and cleaned in hot alcohol.

«TEMPERING STEEL.»

The best temperature at which to quench in the tempering of tool steel is the one just above the transformation point of the steel, and this temperature may be accurately determined in the following manner, without the use of a pyrometer. The pieces of steel are introduced successively at equal intervals of time into a muffle heated to a temperature a little above the transformation point of the steel. If, after a certain time, the pieces be taken out in the reverse order they will at first show progressively increasing degrees of brightness, these pieces being at the transformation point. When this point is passed the pieces again rapidly acquire a brightness superior to that of their neighbors, and should then be immediately quenched.

I.—Heat red hot and dip in an unguent made of mercury and the fat of bacon. This produces a remarkable degree of hardness and the steel preserves its tenacity and an elasticity which cannot be obtained by other means.

II.—Heat to the red white and thrust quickly into a stick of sealing wax. Leave it a second, and then change it to another place, and so continue until the metal is too cool to penetrate the wax. To pierce with drills hardened in this way, moisten them with essence of turpentine.

«To Temper Small Coil Springs and Tools.»—To temper small coil springs in a furnace burning wood the springs are exposed to the heat of the flame and are quenched in a composition of the following preparation: To a barrel of fish oil, 10 quarts of rosin and 12 quarts of tallow are added. If the springs tempered in this mixture break, more tallow is added, but if the break indicates brittleness of the steel rather than excessive hardness, a ball of yellow beeswax about 6 inches in diameter is added. The springs are drawn to a reddish purple by being placed on a frame having horizontally radiating arms like a star which is mounted on the end of a vertical rod. The springs are laid on the star and are lowered into a pot of melted lead, being held there for such time as is required to draw to the desired color.

It is well known that the addition of {684} certain soluble substances powerfully affects the action of tempering water. This action is strengthened if the heat-conducting power of the water is raised by means of these substances; it is retarded if this power is reduced, or the boiling point substantially lowered. The substance most frequently used for the purpose of increasing the heat-conducting power of tempering water is common salt. This is dissolved in varying proportions of weight, a saturated solution being generally used as a quenching mixture. The use of this solution is always advisable when tools of complicated shape, for which a considerable degree of hardness is necessary, are to be tempered in large quantities or in frequent succession. In using these cooling fluids, care must be taken that a sufficient quantity is added to the water to prevent any great rise of temperature when the tempering process is protracted. For this reason the largest possible vessels should be used, wide and shallow, rather than narrow and deep, vessels being selected. Carbonate of soda and sal ammoniac do not increase the tempering action to the same extent as common salt, and are therefore not so frequently employed, though they form excellent additions to tempering water in certain cases. Tools of very complicated construction, such as fraises, where the danger of fracture of superficial parts has always to be kept in view, can with advantage be tempered in a solution of soda or sal ammoniac. Acids increase the action of tempering water considerably, and to a far greater extent than common salt. They are added in quantities up to 2 per cent, and frequently in combination with salts. Organic acids (e. g., acetic or citric) have a milder action than mineral acids (e. g., hydrochloric, nitric, or sulphuric). Acidulous water is employed in tempering tools for which the utmost degree of hardness is necessary, such as instruments for cutting exceptionally hard objects, or when a sufficiently hard surface has to be given to a kind of steel not capable of much hardening. Alcohol lowers the boiling point of water, and causes so vigorous an evaporation when the water comes in contact with the red-hot metal, that the tempering is greatly retarded (in proportion to the amount of alcohol in the mixture). Water containing a large quantity of alcohol will not temper. Soap and soap suds will not temper steel; this property is made use of in the rapid cooling of steel for which a great degree of hardness is not desirable. When certain parts of completely tempered steel have to be rendered soft, these parts are heated to a red heat and then cooled in soap suds. This is done with the tangs of files, knives, swords, saws, etc. Soluble organic substances retard the tempering process in proportion to the quantity used, and thus lessen the effect of pure water. Such substances (e. g., milk, sour beer, etc.) are employed only to a limited extent.

«To Caseharden Locally.»—In casehardening certain articles it is sometimes necessary, or desirable, to leave spots or sections in the original soft uncarbonized condition while the remainder is carbonized and hardened. This may be effected by first covering the parts to be hardened with a protecting coat of japan, and allowing it to dry. Then put the piece in an electroplating bath and deposit a heavy coat of nickel over the parts not protected by the japan. The piece thus prepared may be treated in the usual manner in casehardening. The coat of nickel prevents the metal beneath being carbonized, so it does not harden when dipped in the bath.

A plating of copper answers the same purpose as nickel and is often used. A simpler plan, where the shape of the piece permits, is to protect it from the action of the carbonizing material with an iron pipe or plate closely fitted or luted with clay. Another scheme is to machine the parts wanted soft after carbonizing but before hardening. By this procedure the carbonized material is removed where the metal is desired soft, and when heated and dipped these parts do not harden.

«To Harden a Hammer.»—To avoid the danger of “checking” a hammer at the eye, heat the hammer to a good uniform hardening heat and then dip the small end almost up to the eye and cool as quickly as possible by moving about in the hardening bath; then dip the large end. To harden a hammer successfully by this method one must work quickly and cool the end dipped first enough to harden before the heat is lost on the other end. Draw the temper from the heat left about the eye. The result is a hammer hard only where it should be and free from “checks.”

«Hardening Steel Wire.»—Pass the steel wire through a lead bath heated to a temperature of 1,200° to 1,500° F. after it has previously been coated with a paste of chalk, so as to prevent the formation {685} of oxides. The wire is thus heated in a uniform manner and, according to whether it is desired hard or elastic, it is cooled in water or in oil.