For correct mixing, add plaster to water, do not drop lumps in. For proportions use chart. Slake for two minutes then stir by hand or spoon for two to three minutes. Work plaster up form bottom tom combine with water on top. When a finger drawn across the surface leaves its impression, mixture is ready.

Mixing ratios: 1 qt. water to 2 lb. 12 oz. plaster; 1 gal. water to 11 lb. plaster.

For molds, use 2.5 lb. of plaster to 1 qt. water. Add plaster to water dropping it in slowly. Allow to stand for five minutes. Stir vigorously with spoon until uniformly even. Use immediately.

For casting add slightly less plaster to the water make a more fluid mixture. This is essential to obtain a sharp, smooth cast. After pouring in to the mold, tap mold to bring air bubbles to the surface. Do not pour too rapidly.

For retouching add one part plaster to two parts water and stir vigorously. Apply with brush. When plaster thickens, continue application with spatula. Wet thoroughly the surface being retouched.

For mending and joining, mix in same proportion as for casting. It is important that the parts to be joined should first be water soaked.

To hasten the setting of plaster, add a few pinches of common salt to the water. Setting is retarded by adding animal glue or lemon juice. Plaster can be made weather proof by impregnating with boiled linseed oil, boiling in mixture of beeswax and paraffin, or impregnating with plastics.