plaster question


Sr Member
Gone but not forgotten.

United States Gypsum Company offers a full line of HYDROCAL™ Brand Gypsum Cements that possess greater strength and hardness than standard industrial plasters. HYDROCAL™ Brand Gypsum Cements require less water for mixing, producing casts that are less porous, easier to paint, heavier, and more durable. Medium High-Expansion HYDROCAL™ Cement is a specially formulated gypsum cement having unique characteristics. This material expands uniformly in all directions and compensates for metal shrinkage during metal casting. Expansion values can be controlled by the quantity of water used in the mix.

HYDROCAL™ Gypsum Cement products from United States Gypsum Company's Industrial Products Division are available in several grades, specially formulated for specific applications. HYDROCAL™ Brand Gypsum Cements possess greater strength and hardness than standard industrial plasters or plaster of paris. HYDROCAL™ FGR 95 Gypsum Cement is designed to set fast, provide high strength and permit the fabrication of strong, resilient glass-reinforced products. HYDROCAL™ B-11, which is used primarily in tooling and prototyping applications, provides users with the strength they need, but with a high degree of plasticity. Finally, HYDROCAL™ Gypsum Cement, when used in statuary and art applications, is adaptable for either solid or hollow-art casting.


Sr Member
For what purpose are you asking?

Ultracal-30 is also a Strong Gypsum, I use both for various projects...

Dark Shadow

Sr Member
Absolutely Hydrocal is much stronger than PoP. Its a gypsum that natuarally repells water. Its commonly used for molds when using latex. The Hydrocal will whisk the moisture right out of the latex and through itself into the atmosphere. Ive dropped small molds on the table occasionally and they havent broken. I actually have to put some effort into breaking unwanted molds.