Part 4 - Take the rubber off the original. Be careful! It will be inside-out. Now you can sprinkle a little talc on it and turn it inside-in. Put it into the fiberglass case you made, bolt or clamp the case closed, invert the case so that it is sitting on that big base we where talking about. Mix your concrete and fill the mold. Let it sit to cure for a couple of days. This is the test run for this mold and case so you want the concrete extra hard when you do your first de-mold.

Part 5 - Unbolt the case and take out your casting. Carefully take the rubber mold off the casting. If you are a skilled mold maker it should be right the first time!! If not you need to look at any problem areas and decide what you can do to correct them.

Now you can see why the rubber or latex molds cost so much and why they take a couple of weeks or more to make.

The building time can be shortened by using fast drying silicone based rubber, it is a little more expensive but.... Plaster can be used instead of fiberglass if the mold is not going to be used a lot. This is cheaper but not nearly as good as fiberglass.

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