Plaster

Plaster is a strong and highly absorbent material with many uses. Common uses of plaster in ceramics include mold-making, bat production and creating surfaces for wedging and drying clay. At The Ceramic Shop we carry a number of different types of plaster which vary in strength, set time and application.

Pottery Plaster No. 1 is a great all-purpose plaster. It is commonly used for making slip molds and press molds. It is ideal for this purpose because of its fine particle size, which allows for great detail. When mixing Pottery Plaster, the consistency should be approximately 70 parts water to 100 parts plaster, and the set time is about 27 - 37 minutes. Compared to Hydrocal, Hydrostone and Ultracal, Pottery Plaster is weaker and more susceptible to wear.

Hydrocal is a plaster product that has a strength of compression twice that of Pottery Plaster.  It is a good plaster for making case molds.  When mixing Hydrocal, the consistency should be approximately 45 parts water to 100 parts plaster, and the set time is about 25 - 35 minutes.

Hydrostone is a very strong plaster product, and is suitable when high-strength and wear resistance is necessary. When mixing Hydrostone, the consistency should be approximately 32 parts water to 100 parts plaster, and the set time is about 17 - 20 minutes. Hydrostone is the strongest of the plasters we carry.

Ultracal is a low absorption gypsum cement that is made for close tolerance tooling. When mixing Ultracal, the consistency should be approximately 38 parts water to 100 parts plaster, and the set time is about 25 - 35 minutes.

FGR Plaster has a long set time, allowing for fabrication of strong, fiberglass-reinforced items. When mixing FGR, the consistency should be approximately 72 parts water to 100 parts plaster, and the set time is about 27 - 37 minutes.