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How to Make a Mold

Utrecht

When ready to make a mold, the most basic method is:

1. Wear a particle mask; mix plaster according to package instructions

2. Literally cover the entire model with plaster, down to the board beneath (although more complex shapes may require a multiple piece mold). A thin, milky plaster should be flicked on with the fingers until all is covered.

3. Thicker plaster is smoothed on, several inches thick.

4. Finally, cheesecloth dipped in plaster is draped over to give strength; for smaller models, Rigid Wrap plaster gauze is ideal.

5. Allow mold to set overnight; remove from the board underneath.

6. Using a large metal loop tool, begin digging out the clay inside through the hole in the bottom.

7. Outdoors, wash out remaining clay with a garden hose, making absolutely sure none remains.

8. Allow mold to dry completely.

9. Pour shellac into mold to coat the entire inside. Allow to dry completely.

When ready to cast from the mold:

1. Create a stable base for the mold using a plastic bucket weighted with sand.

2. Estimate the amount of plaster (should be a harder variety than the mold) or cement needed to fill the mold, and add extra just in case of a mistake.

3. Spray the inside of the mold with a thick coating of cooking spray as a release agent.

4. Mix plaster or cement according to package directions. In general, dry material should be poured into water, not the other way around. Break up lumps.

5. Have an assistant hold the mold steady to avoid tipping over. Pour cement or plaster until mold is completely full.

6. Allow to set completely.

7. Using a hammer and chisel, carefully strike the mold to break it away from the sculpture inside.

8. Carefully pick away any remaining bits of the mold from the sculpture.

9. Paint or finish the completed sculpture any way you like.

Plaster can actually be manipulated manually as it cures.

Gloves or barrier cream are recommended to avoid lime burns.

Make an armature from aluminum wire mesh, and cover with Rigid Wrap bandages.

Mix plaster according to package directions, and allow you to achieve a cheese-like consistency.

Apply handfuls, building up desired form.

While still wet, carve with a fettling knife and plaster rasps.

An alternate method for mess-free plaster sculpture is to mix and mold entirely in a heavy food storage bag. Simply squeeze through the bag into the desired shape.

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