2023. To Dress Plaster of Paris with Wax in Imitation of Alabaster

2023.    To Dress Plaster of Paris with Wax in Imitation of Alabaster. Dip the cast or model, previously warmed, and suspended by a fine silken cord or wire into the purest white wax, melted in any suitable vessel. The operation should be repeated until the liquid wax begins to rest unabsorbed on the surface of the plaster, when the article must be placed aside (suspended) until the next day, when it may be polished with a clean brush. None but the hardest, purest, and whitest wax will do for the above purpose. That commonly sold is mixed with spermaceti, stearine, or tallow, and not unfrequently with Japanese wax and. potato starch. (See No.

2024. To Render Plaster Figures Durable

2024.     To Render Plaster Figures Durable. First thoroughly dry the plaster figure in a warm dry atmosphere; place it in a vessel and cover it with the clearest linseed oil, just warm. After 12 hours, take it out, drain, and let it dry in a place free from dust. "When dry it will look like wax, and can be washed without injury.

2025. To Harden Plaster

2025.     To Harden Plaster. Mix up the plaster of Paris with a weak solution of gum arabic (1 ounce to 1 pint of water); or, for common purposes, a weak solution of size. This not only renders the plaster harder, but gives the surface a pleasing smoothness.

2026. To Harden Imitation Alabaster with Alum

2026.    To Harden Imitation Alabaster with Alum. Suspend the article by a fine silken cord or wire in a strong and perfectly clear solution of alum, letting it remain until the alum crystallizes on the surface; then polish with a wet cloth.

2027. To Make Hard Plaster of Paris

2027.      To Make Hard Plaster of Paris. Mix with weak alum water, instead of water, for casting; or, a solution of 11/2 or 2 ounces of gum-arabic to the pint of water; or, for common purposes, a weak solution of size may be used.

2028. To Harden Plaster with Sulphate of Potassa

2028.    To Harden Plaster with Sulphate of Potassa. If equal parts of common calcined plaster of Paris and of sulphate of potassa be mixed together, they will harden in a moment with less than an equivalent weight of water; so much so, indeed, that the mixture cannot be poured out of the vessel. If, however, 1 part of each of the salts and 2 of water be used, they form a mass which cannot be poured out, and the surface of which will be found coated with a crust of sulphate of potash. The rapidity of hardening, therefore, can be made to vary with the percentage of water, the mass solidifying even if 6 parts of water be used.

2029. To Stain or Color Alabaster

2029.    To Stain or Color Alabaster. This is effected by mixing with the water used for working the gypsum, any of the ordinary pigments or colored solutions that are not decomposed by contact with sulphate or carbonate of lime. A little sienna in very fine powder, or ground with water, imparts a good color for busts, medallions, etc.. For rough and architectural purposes, the colors are commonly added to a solution of clear size, which is then made into a paste with plaster. In this manner colored stucco of great hardness and durability is produced. Objects formed from the solid alabaster may be stained in the same way, and with the same materials, as marble. (SeeNos. 2036, etc..)