Or take 2 quarts of alcohol, and mix 3 ounces of rotten stone, 5 ounces of pumice stone, and 6 ounces of lampblack with enough of the al cohol to form a stiff paste. Grind this mixture in a paint rain. Dissolve 7 ounces of shellac in the remainder of the alcohol and mix the whole. Shake or stir before using. This quantity will give two coats on about 30 square yards of blackboard. Let the first coat dry thoroughly before applying the second.
To Imitate Stonework.—An imita tion of a stone surface may be made either by mixing fine road dust or sand with paint, or by sprinkling a freshly painted surface with sand from a shaker having holes in the top similar to a pepper box. Mix 100 pounds of road dust, 25 pounds of white lead ground in oil, 50 pounds of whiting, 7 pounds of umber, and 3 gallons of lime water. Grind with linseed oil. This gives Lt solid stone color.
Or prepare an ordinary oil paint with white lead and suitable coloring matter, and while the surface is wet dust fine sand over it from a shaker. This imitates a stone surface.
Soluble Glass Paints.—Silicate of sodium or soluble glass may be used as a vehicle for coloring matter, es pecially for walls and ceilings, as it produces a very hard and durable surface. The coating of soluble glass containing coloring matter may be followed with a coating of clear solu ble glass. This substance is much cheaper than the oil and lead paint, and has the advantage of being par tially fireproof. It may be mixed with glycerin for flexible surfaces, as cloth, paper, etc.
Pigments suitable to use with solu ble glass are terra di Sienna, green earth, ocher, red and yellow earth, Nuremberg green, chrome green, and ultramarine.
Acid-proof Paint.—Mix pulverized asbestos with a sirup solution of wa ter glass to the consistency of paste until free from lumps. Thin with a solution of water glass as free from alkali as possible, and apply with a paint brush. This dries as hard as glass and resists the action of acid.
Barrel Paint.—Dissolve S pounds of rosin in 1 gallon of boiling linseed oil by boiling in a kettle and stir ring until dissolved. This mixture is known as gloss oil. Use equal parts of gloss oil and benzine as a vehicle with lead, zinc, or anything you de sire to use as a pigment. Stir well
before using.
Glue Paint for Kitchen Floors.— Mix 3 pounds of spruce yellow with 2 pounds of dry white lead. Dis solve 2 ounces of glue in 1 quart of water with gentle heat. When near ly boiling, stir in the mixture and continue stirring until it thickens to the consistency of paste. Apply hot with a common paste brush.
To Mix Colored Paints.—The col ored pigments used in mixing colored paints come ground in oil in the fol lowing colors: white, yellow, red, blue, green, brown, black. They also come in the form of powders. To prepare these for painting, it is only necessary to mix them with the prop er amount of boiled linseed oil, with the addition of a thinner or dryer if desired. They are then ready to use.
Other tints and shades are pre pared by mixing and blending the above colors. The following are among the principal pigments used in mixing colored paints: White Paint.—White lead is usual ly the basis of white paint, but it is often adulterated with barytes, oxide of zinc, prepared chalk, whiting, lime, or road dust. All paint intended to show a pure white should have about ounce of Prussian blue mixed with every 2 pounds of white lead, other wise the lead appears as a stone color and not white.
To mix white paint, use pure boiled linseed oil, and thin as desired ac cording to conditions with oil of tur pentine.
Yellow Paint.—The yellows are usu ally ochers, chromate of lead, and various adulterants.
To prepare chrome yellow pigment, dissolve in hot water 5 pounds of sugar of lead and 5 pounds of Paris white. Dissolve separately in hot water 61 ounces of bichromate of pot ash. Add the bichromate solution to the former, mix, and let stand 24 hours. Strain through muslin and expose to the air to dry. Mix with boiled linseed oil.
To make a cheap yellow paint, take 60 pounds of whiting, 40 pounds of ocher, and 5 pounds of white lead ground in oil. Grind with raw lin seed oil and mix with boiled linseed oil.
Red Paint.—The reds are usually red oxide of lead, ochers, oxides of iron, red oxide of copper, vermilion, bichromate of lead, carmine, and mad der and other lakes. Mix any of the above with boiled linseed oil and ap ply.