Plaster, Stone and Gypsum Products

plaster

See our Basic Materials Page for definitions and more details on these products.

Packaged in buckets.


Molders' Plaster aka #1 Pottery Plaster

This is tooling plaster used to make absorption molds. 2,000 psi. The set time is 27-37 min.

Add Model # Description Price
MP-10 Molders Plaster, 10 lb. $12.00
MP-25 Molders Plaster, 25 lb. $20.00
MP-50 Molders Plaster, 50 lb. $32.00

UltraCal 30

This is a tooling gypsum used to make molds. It can be used for absorption molds. It is a favorite for making molds for foam latex. 6,000 psi. The set time is 25-35 min.

Add Model # Description Price
CAL30-10 UltraCal 30, 10 lb. $15.50
CAL30-25 UltraCal 30, 25 lb. $26.50
CAL30-50 UltraCal 30, 50 lb. $41.00

Hydrostone

This casting material is very strong and very white. It cannot be "Built-up" into walls. 10,000 psi. The set time is 17-20 min.

Add Model # Description Price
HYD-10 Hydrostone, 10 lb. $15.50
HYD-25 Hydrostone, 25 lb. $26.50
HYD-50 Hydrostone, 50 lb. $41.00

Hydrocal White

This casting material is very white. It can be used as a dental plaster. 5,000 psi. The set time is 25-35 min.

Add Model # Description Price
HYDW-10 Hydrocal White, 10 lb. $16.50
HYDW-25 Hydrocal White, 25 lb. $23.00
HYDW-50 Hydrocal White, 50 lb. $31.00

Hydrocal 105

This is a dental Stone with a yellow tint. 6,000 psi. The set time is 7-10 min.

Add Model # Description Price
H105-10 Hydrocal 105, 10 lb. $16.50
H105-25 Hydrocal 105, 25 lb. $23.00
H105-50 Hydrocal 105, 50 lb. $32.00

Mixing Ratios for Plaster and Gypsum

These are factory (high volume) recomendations. Your mixtures will probably be dryer than these.


Casting Plaster 65 parts water by weight to every 100 parts of product.
Hydrocal 105 40 to 42 parts water by weight to every 100 parts of product.
Hydrocal White 45 parts water by weight to every 100 parts of product.
Hydrostone 32 parts water by weight to every 100 parts of product.
Molders' Plaster or No. 1 Pottery Plaster 70 parts water by weight to every 100 parts of product.
UltraCal30 38 parts water by weight to every 100 parts of product.

Example: Suppose you wish to mix 100 lbs. of Hydrostone. For the factory recommended mix add 32 lbs. of water.

Notes:

Generally the less water the stronger the end product will be. Most artists mix by sight, which is often a dryer batch than the factory recommendation. A wet batch takes longer to harden and will not have sharp detail. A dry batch usually will have air bubbles or pockets and may harden too quickly. Do not use soft water. Don't breathe in the dust from these products. Don't use for body casting directly on the skin. It is normal for these products to get hot during the setting process.

For best results follow this procedure:
  • 1) Measure out the powder and water in advance
  • 2) Sift the powder into the water. You should start with about 3/4 of the water needed and then use the remaining water later to adjust your batch.
  • 3) Stir with a Jiffy Mixer
  • 4) Do not put a new batch of plaster over a partially hardened mix.