Molds: The big secret of the sculpture trade
The question I get asked most is, “Can you teach me how to make molds?” and my answers are always evasive. Not because this is a huge trade secret, but because making a good mold is a painstaking engineering project. It is critical that it be done right or your original artwork may be ruined beyond repair. It is not something that can be taught in an afternoon. It is necessary to personally use the materials to experience their properties—something that can’t be learned from reading a description alone. I learned how to make basic plaster molds during several semesters in undergraduate sculpture classes. Then I did foundry work and learned about latex molds and casting in plastics. I highly advise anyone interested in moldmaking to take a good class. The Polytek Company in Easton, Pennsylvania offers these from time to time. They also have videos on moldmaking which I’ve never seen, but I would welcome feedback from readers who have.
Armatures: The other big secret of the sculpture trade
The question I get asked next most often is, “Hey, how does that big piece of clay stay in one piece?” and the answer is: an armature. I start with a great big heavy piece of wood for the base and screw into it sections of 1” metal pipe from the hardware store to form a minimal (very minimal) skeleton that is smaller than the final size of the piece. Using aluminum armature wire or stainless steel fence wire, I secure chunks of pink contractor’s styrofoam to the armature to bulk up the piece in a lightweight fashion before piling on the clay (I read recently that Bernini’s studio used straw and horse dung over a wood frame, so we’ve come a long way). The object is to provide an extremely stable structure for a lot of extremely heavy clay, plaster, or whatever. Louis Slobodkin’s “Sculpture: Principles and Practice” (Dover Books) has wonderful illustrations of armatures that speak volumes about armature engineering (and was done before the days of Styrofoam, for any purists out there). This book is also extremely valuable for showing beaux-arts sculpture practices in their entirety, including plaster moldmaking.