Sculpting an Ambull: Molding and Casting Continued

Once the first part of the mold had cured, the other side was removed. This consisted of the bottom of the mold box and the clay that was used as a barrier. The master and the sprues remain in place in the first part of the mold.

I use Vaseline as a separating agent between the two mold parts. RTV silicone will stick to itself really well, so a barrier cream is vital, at least on the rubber itself (most other materials are fine with silicone). I had some really old silicone that I was diluting with some silicone thinner, so these were definitely not ideal mold-making situations. Hopefully at some point in the future I can offer some examples of a more professional approach.


This picture shows the other component of the Ambull, the legs and back of the upper body. Same concepts applied: LEGO box, clay wall around the master, sprues cut from wood (found the dowels to be a bit better than the square stock). The little divots in the clay were pressed in with the back of a paintbrush. Once the rubber is poured in, they will serve as pegs to register the front and back parts of the mold.