Mold Making
Mold making is a crucial step in the lost wax process. It requires the capturing of detail in an artist's sculpture and being able to produce the same detail in a bronze casting. A hundred years ago, molds were made using plaster and gelatin. Gelatin molds did not have a very long shelf life and were also not very durable. Wax sticks to gelatin molds and protein based gelatin molds will fall apart after a few uses and will develop actual mold such as Penicillium and Aspergillus. Even more recently, some molding materials can include lead or other ingredients that can cause health issues. Some molds used algae as a base but also had a short shelf life as they were mostly made of water and would shrink as they dry.
The best quality molding material we have found is silicone rubber. We have a long standing relationship with Silicones, Inc. Their silicone rubber allows us to make master molds that are usable for over a decade with proper storage (depending on the complexity of the sculpture.) Based in North Carolina and with all of their products made in the USA, they have worked on their formula with us to ensure our molds are as accurate, durable, and versatile as possible for sculpture molding. Our molds are able to be used with a wide variety of clays and other sculpting materials.
This silicone rubber is able to capture high levels of detail. Our specialists have the expertise to capture details so precise it even includes fingerprints.
After the rubber master mold is finished a protective mother mold is made. We use a plaster mother mold reinforced with natural fibers to create a sturdy outer shell. The plaster keeps the rubber in its shape without warping or flexing. Therefore, our natural fiber reinforced plaster helps create more accurate waxes. It also uses more sustainable and environmentally friendly materials than fiberglass reinforced by resins.
Once the molding process is complete, the finished mold is opened up and the original sculpture is removed. Because the rubber is closely applied in order to capture every detail, removing it often results in portions of clay sticking to the rubber. This does mean that an artist's original clay work will sustain some damage from the molding process.