How to Make Casting Plaster

Plaster can be used to make casts of hands and other body parts.

Whether you’re making a plaster imprint of your pregnant belly or you’re a serious artist working on a sculpture, the first step in any plaster casting is making the actual plaster. You can pick up the plaster at any hardware store and even some superstores and have your plaster mixed up and poured in no time. There are several key steps to follow to ensure a sharp, smooth casting plaster.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Plaster
• Water
• Spoon
• Gallon milk jug

1. Cut a milk container in half. Always use a mixing container a little larger than the cast you are making.

2. Pour in 2 quarts of water for every 2 lbs. of plaster.

3. Put water in first, then plaster. Break up clumps. Stir the mixture with a spoon, scraping the bottom to mix well, for 10 minutes.

4. Watch for the mixture to get warm and thicker. When you can draw a line on the surface and it leaves an impression, the plaster is ready.

Tips & Warnings

• Use slightly less water for a more fluid mix and a sharper finished cast when casting molds.

• After pouring casting mix into molds, tap lightly to bring bubbles to the surface.

• Always pour slowly into the molds.

• You can use Tupperware containers, but they tend to crack when the plaster dries.

References

• Aldax: How to Mix and Pour Casting Plasters