How to make molds of your polymer clay sculptures and use them to cast hydrostone sculptures. Page Three.
After the mold has fully set, carefully cut the cardboard away using a blade or an xacto or hobby knife.
In small cuts, cut through to the sculpture in one line down the back of the sculpture (or whatever part has the least amount of detail). Make sure you think about where this seam is as it may need a bit of sanding in the final cast. If the seam runs down a detailed area, then it will take more time and effort to sand the sculpture. Don't cut the mold in half, you only want to create enough space that you can wriggle your sculpture out.
This is where how flexible the silicone is comes in handy. Because the mold is so stretchy, you can carefully stretch the mold open to remove your sculpture and the mold will still bounce back into place. The less you have to cut your mold, the less seam line you will have to sand away later. Wriggle the sculpture out carefully; you don't want to damage the mold or your original sculpture.
Spray the inside of the mold with some more Rapid Release spray and close it up. Put some pieces of cardboard around the mold and secure it with rubber bands. The cardboard stops the rubber bands from squeezing the mold too tight and distorting it. Of course you still need to make sure you don't have the rubber bands too tight around the cardboard.
Also, mix together some Hydrostone in a disposable container (Mix ratio powder to water- 100:32). Take your time to make sure that the mix ratios are correct.
Pour the Hydrostone into the mold in a thin stream like you did with the silicone. Also, tap the mold to release the air bubbles. Allow the cast to set properly before taking off the rubber bands. I like to let it set for a couple of hours before removing it from the mold.
When you remove your cast from the mold, wriggle it out slowly so as not to damage the cast. Keep in mind that some parts may not have set completely and may still be a little brittle. Leave the cast sit over-night out of the mold to dry fully before painting.
Once it's dry you can start to paint! I suggest coating the cast in a base coat because the acrylic paints may seep into the plaster. Make sure you seal it with an acrylic paint spray sealer when you're finished.
You can create many casts of the same sculpture using this method. It's great for ornaments for Market Stalls and the like. REMEMBER: Although you have constructed it by hand and painted the casts individually, this DOES NOT make them one-of-a-kind (OOAK). Sculptures made with a mold fall under either a Limited or Open Edition collections.
I hope you have enjoyed this "How to Make Molds" Tutorial!