When casting into plastic or rubber molds that can't be disassembled, some sort of mold release will make it easier to get the finished piece out of the mold. In a brand new plastic mold, it's not necessary to use release, but over time and after the mold has been used for a few castings, mold release will help a lot.

You should not be using release on any projects where you're using ShapeCrete in the Clay-Like Consistency. For those projects mold release will only make it more difficult or impossible to pack the mix into the form.

There are a lot of types of mold release, from the professional aerosols that you'll find in Model Making shops, to ordinary cooking spray or oil.

In this example we're going to use an aerosol cooking spray.

STEP 1: Spray Mold Release

Clean the mold with soapy water and dry it with a towel before beginning. Make sure any debris is blown out of the form. Spray a very light coat of cooking spray in the mold. Don't use too much, as anything oil based can discolor the piece or cause very small air bubbles to form in the surface.

Just a quick, light dusting is all the mold needs.

STEP 2: Mix and Pour

Mix ShapeCrete to a Castable Consistency and fill your form.

STEP 3: Demold

After the piece has cured, carefully break the seal between the mold and the finished piece by working the plastic loose around the edges. If the shape doesn't have a lot of detail, it should pop right out. On highly detailed pieces, work it out very slowly to avoid chipping the details.