Art Term Tuesday: Glass Casting

Kaitlin Binkley, Marketing Coordinator

Opening soon at the Fort Wayne Museum of Art is the 46th Annual International Glass Invitational Award Winners exhibit in which glass sculptures by the best in the world will be on display. These beautiful works of art come into being by many processes, employing techniques that the average person might never have encountered. With that in mind, let’s explore one of the more popular glass making processes: cast glass.

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(Above) Seven Bodies, exhibited at FWMoA earlier this year, showcases seven pieces all made from cast glass. (Below) A close up look at each piece in the series. Peter Bremers, Seven Bodies, Cast Glass, 2017. Photos taken by Alyssa Dumire.

Many of the works in the exhibition were created using different “casting” methods. Glass casting is a process by which a mold is created and hot molten glass is poured into it to fill the form, thus taking on the form of the mold. Once the glass is cooled enough to harden, the mold is removed. The mold can be made many different ways, so long as the material used is heat resistant to maintain the shape even in extreme temperatures. An ancient example of casting is sand casting, as sand has a very high melting point and so keeps its shape as the molten glass is poured into the form. To create the mold, a model of the final sculpture made of wood, clay, or other less desirable material is pressed into the sand to create a clean impression. The model is removed and molten glass is poured in its place. The glass fills the mold and the sand absorbs the heat, hardening the glass until it can be removed from the mold and placed in what’s known as the annealing kiln, in which the temperature is gradually decreased over the course of several hours to give the glass structural integrity.

Casting can be accomplished in other ways without the use of sand, and in today’s art world, glass artists experiment with different technologies to create their visions. Kiln casting is a popular method in which a model is created, an opposite impression (called an investment) is cast in any heat resistant material, and the model is removed for the glass to be added. The glass can be poured into the investment or chunks of glass can be placed in the investment, then heated to melt and fill the void. These particular glass sculptures, of solid glass, are the heaviest, and their size can be as massive as the kiln in which the artist can access.

It is important for the artist to know that any textures, lines, or surface details desired in the final sculpture will need to be included in the casting model. The model is, in a sense, a carbon copy of what the final work will look like, just in a different material. It’s important to appreciate, too, that the process of creating glass sculpture is a process of scientific precision and accuracy as much as it is a process of creation, and to achieve the incomparable beauty of what we observe in contemporary studio glass, details must be accounted for and plans must be followed.

In the glass exhibition opening at FWMoA July 14, observe closely the textures of the many diverse sculptures you will see, and look for clues to test this brief education in casting. Does the glass have a rough texture, like sand? A smooth surface like metal? Are there different textures on different parts that have maybe been joined together? Imagine, too, what each sculpture may have looked like in wood or clay, and judge for yourself if glass, indeed, is the superior material for these wondrous sculptures.

For pictures of this step-by-step process, we invite you to visit this website. https://www.polytek.com/tutorial/kiln-casting-glass-process

 

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