Plaster, Hydrocal

ORDER QUANTITY LIMIT: 100 lbs per customer per week. USG has stopped making Hydrocal, and this is our remaining stock. When it's gone, we don't have a replacement yet.

USG Hydrocal White Gypsum Cement is a hard, durable gypsum cement for sculpture, statuary, architectural details, lamp bases and general casting. It is much harder and less absorbent than pottery plaster, so it is not a substitute for pottery plaster in slip-casting molds. For those, use Arcosa Pottery Plaster.

Typical properties (USG data)

Hydrocal uses much less water than pottery plaster. Don't use the pottery plaster chart. Mixing method: Instructions for Mixing Plaster.

Why the limit? In 2026 USG closed the Oklahoma plant that made Hydrocal, Hydro-Stone and No. 1 Pottery Plaster. The limit lets more customers get some. More about the USG closure.

Plaster dust irritates eyes, skin, nose and throat. Wear a dust mask when mixing, and never pour plaster down a drain.