How To Vent a Silicone Mold to Eliminate Bubbles In Casting

The first step is to prepare a mold box that will accomodate the original model. Be sure to factor a minimum 1/2'' (1 cm) clearance into the mold dimensions. Use sulfer-free clay segments to elevate the model 1/2'' (1 cm) from the mold box base board. Then, secure the model onto the clay perimeter base and fill holes in the model with clay. Smooth and level the modeling clay surface and edges. Nex, press acorn nuts into the clay around the perimeter of the model to create registration points for the mold halves. The bottom half is ready to have the first layer of rubber applied.