Alexandra Heintzelman Sharma
Each Fall, Winter and Spring I offer a sculpture class in clay modeling, waste mold casting, slab casting, and sand casting at the Hilton Head Art League Academy on Cordillo Parkway, Hilton Head Island, SC Sudents in this Winter course have been creating sculptures in the round using pottery clay, We do not fire the sculpture but instead, cast each in plaster using a process called, "waste-mold casting".
When the clay sculpture has been realized, we begin the process of making a plaster mold of the sculpture by flicking plaster onto it until it has a durable shell of plaster. Once the plaster is dry--approximately 15 minutes-- the clay is pulled out of the plaster mold and the mold washed out in preparation for pouring it with plaster for the final form. A release agent is brushed into the mold and then plaster is poured in and allowed to harden. When the plaster is hard, the outside plaster mold/shell is chipped away and the sculpture is released from inside the mold--an exact and true copy of the original clay sculpture! The chipping off of the mold destroys the mold--hence the name, waste-mold casting. This process is an interim stage to having the sculpture cast in bronze at a foundry.
The final step is to color the plaster through a series of layers of colors to create a patina--or to leave it white but with a waxed surface that changes the white to a soft ivory color.
The following photographs show students at work at various stages of the creative process
Applying layers of color on the finished sculpture to create a surface patina that in this case will be bronze-like.
Detail of a reclining figure in process of being realized
Using small detail tools on a clay bust
Photographing some examples of bronze sculptures
This page was last updated on: March 21, 2017
.Almost ready to make the mold by covering the sculpture in a layer of plaster
A finished sculpture after the plaster mold has been chipped away
The clay head completely covered with plaster which forms the mold.
The plaster imold is hardened and now we use clay tools to remove the clay.
Alex (on right) checking the plaster of the newly formed mold to see if it is hard enough to begin removing the clay from inside.
Removing the clay from inside the plaster mold
Using plaster carving tools to achieve the over-all form and surface