Saturday, August 6, 2011

Mold Making Part 2: Clay Build-up and First Plaster Pour

The next step is to build up the first half of the mold underneath the sculpt. The clay is built up bit by bit around the sculpt until it reached the midsection of the character. The squares on the corners are keys that are used to fit the second half of the mold onto the top. The puppet has tie downs on its feet which are impressed into the clay. This helps when placing the final armature in the mold, the tie downs of the final armature can be lined up with these impressions.

Next a clay wall is built around the mold. This will allow Justin to pour in the plaster over the sculpt to create the top half of the mold.

Once the clay wall is finished, the next step is to pour in the plaster.

The first coat is called a splash coat, it's thinner than the rest of the coats, about the consistency of a heavy cream.

Once the splash coat is added, a heavier mixed coat is applied, about the consistency of pancake batter.

Next, sheets of burlap are dipped into plaster and criss-crossed onto the next layer. This will make the overall mold much stronger.

After the burlap sheets are added a final coat of plaster is applied, again mixed to the consistency of pancake batter.

Once the final coat is applied, the clay wall can be removed. The plaster has already started to set and harden.

The plaster is then burnished with piece of burlap. Also any ridges and bumps of plaster are removed. This makes the mold much smoother and cleaner and also eliminates any sharp corners that can cut you later!

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