#1 Pottery Plaster - This white plaster is the standard for making molds, sculptures or bats. Mix with water, set in 20 - 30 min. Hydrocal White & Hydrastone - These plasters are good for sculpture, Hydrastone is suitable for outdoors. Instructions for Mixing Plaster - Always mix plaster into water. Product Parts of water by wgt per 100 parts plaster #1 plaster - 70 parts water Hydracal White - 45 parts water Hydrastone - 32 parts water plaster #1 Plaster - 10 pounds 1plaster$5.00 50 pounds plaster50$12.00 50 pounds hydrocal50$16.00 50 pounds hydrastone50$18.00 100 pounds plaster100$22.00 100 pounds hydrocal100$29.00 100 pounds hydrastone100$33.00 500 pounds 1plaster-500$105.00