Heating Things Up and Letting Them Hang.

For some studios that share space with a ceramics lab, slumping is an easily accessible technique of glassworking. It allows the artist to create a number of pieces in a relatively short amount of time. The size of the pieces is really dependent on the size of the kiln that is used and can also be limited by the size of the glass pieces that are being formed.

The slumping process begins with the creation of a simple mold. Unlike the common idea of a "mold," a slumping mold is simply a surface over which the glass will "fall" onto. For example, a form used to shape a plate might just be a simple, smooth mound of plaster. The shapes can vary from simple plates and bowls to more complex forms like rippled lampshades. Part of the beauty of slumping is that you never know exactly what you're going to get. While the form over which the glass sits may show one design, the glass may not come into full contact with the mold and will end up having a few differences than the original shape.

After placing the form in the kiln and the glass piece(s) on top, the kiln is brought up slowly to a temperature where the glass just becomes fluid. The temperature, generally, does not exceed 1200F as molten glass will just run off from the form. After maintaing the piece at the slumping temperature for the desired amount of time, the piece is annealed. Annealing is a process used to distribute the stresses that build up in the piece due to thermal expansion. A glass piece can shrink up to 17% as it cools. Once the piece has reached room temperature, it can be removed from the kiln and finished in the cold shop.