How Is Furnace Glass Made?

Ingredients

• Glass is made from natural ingredients, including sand, limestone and soda ash. Adding recycled glass, known as cullet, into the mix means it does not need heating so long before it becomes molten. This makes a saving for the environment, according to O-I website's video on glassmaking.

Temperature

• The mix will reach 2,850 degrees Fahrenheit to become molten glass, though some furnaces will take the molten glass to 3,000 degrees F.

Handmade Furnace Glass

• Furnace glass starts off as a "glob" or ball of molten glass, also known as a "gather," being taken out of the furnace on a pipe, or "punty." If it is to be hand-blown, a small bubble will be blown into it. The glass-blower will then work it into shape, mark the pattern and extrude it lengthwise. The tube is cut, and the pieces tumbled and fire polished for smoothness. Hand-blowing and working will produce unique bead forms.

Ovals

• The website Shipwreck Beads describes the process of making "ovals" -- beads formed by first encasing a glass "cane" of fused smaller pieces in clear glass and firing the whole in a kiln or furnace before cutting the cane into the small pieces. The result is bold and vibrant eye-catching colors, says the website.

Alternative Method

• Furnace glass is not the only way to obtain glass beads. Bead maker Ann Scherm Baldwin winds molten glass around a small steel rod in a technique known as "lampworking," because in Venice, early bead makers used oil lamps to melt the glass. Modern "lampworker"s use propane burners that give them the exact heat they want.