Inside the Artist’s Studio: How Blown Glass Sculpture Is Made
October 24, 2016

- The Materials Glass is made primarily from the refined sand granules of fused quartz known as silica. Modern glass is approximately 70% to 74% pure silica by weight. The remaining materials may include soda lime or metal oxides, used to help lower the melting point of the silica, as well as colorants to infuse the clear glass with different tints and hues.
- Heating and Shaping The raw materials are first heated to a temperature of 2,000 degrees or more in a furnace. The principal glassblower, known as the gaffer, then removes the molten glass from the furnace, blowing into it from the end of a long pipe or shaping it along a cold steel surface called a marver. If the glass cools to the point where it can no longer be easily shaped, it goes back into the furnace, then blown or shaped again. This process may be repeated many times, until the desired size and shape of the blown glass sculpture is achieved.
- Cooling Glass can crack or shatter if it is moved from hot to cold temperatures too quickly. A special oven called an annealer is used to house the sculpted glass at an initial temperature of 960 degrees Fahrenheit, then cooled gradually over the next 14 hours to create a finished product. Artists may then also grind the surface to remove any sharp edges created by the movement of the piece.