Creating A Torso Mold

Step 1
Preparation

Step 2
Application

To begin, the model applies a thin coating of petroleum jelly to skin. It also aids to release the mold from the suction created as the mold material hardens. A thicker coating is recommended for the pubic region as it also prevents hair from being pulled. In this example, the model wears a shower cap to protect her hair against possible splatter. 

Slow-set dental alginate is very gentle to the skin. Now it is being thickly applied in the consistency of yogurt. It should be thoroughly rubbed onto the skin in a circular motion to remove damaging air bubbles. The alginate we use is the warm water kind for the model's comfort. It takes about 7 minutes to dry so the work must proceed quickly.

Step 3
Support Shell

Step 4
Removal

When dry, the Alginate is very rubbery requiring a support shell, or "mother" mold. We use plaster impregnated bandages for this purpose. Nine inch strips are dipped in to warm water and applied over the alginate. At the edges of the plaster bandage mold we double and triple the thickness of the bandages for added support. The bandages take about 15-20 minutes to dry. They hold the work during casting.

After the bandages have set the mold is carefully removed. At this stage the mold is held tightly against the skin by a vacuum. One must slip a hand around the edges to break the seal. The cast should then pop off. Now the mold should be immediately cast because as the alginate continues to dry it will loose detail. The entire modeling time is about 45 minutes.