Mix together Plasti-Paste® with a 1A:2B by volume mix ratio. Spread the Plasti-Paste® over the entire first half of the model, including the shim. Then remove the clay from the first half of the Plasti-Paste® shell after it has cured.
Apply Sonite® II Wax to the Plasti-Paste® shim and mouth plug. Also, apply Universal® Mold Release over the Sonite® II wax to assure a good release.