Glassblowing, like most other art forms, uses specific materials that are unique to the discipline. If you’ve spent some time in a hot shop, like the St Pete Hot Glass Workshop at The Duncan McClellan Gallery watching the DMG School Project glass artists work, you’ve probably heard terms for materials that left you mystified.
Getting familiar with terminology is a great first step to learning more about any art form, so we’ve put together this guide to help you better understand what these terms mean and how they are used in making glass art.
Batch – The raw materials to be melted into glass such as silica, carbon, and lime. Different batch materials will create different types of glass, such as borosilicate glass or soda-lime glass.
Cullet – Beads of clear raw glass which are melted in a furnace to create molten glass for glassblowing.
Borosilicate Glass – Also called Hard Glass. Commonly used in cookware (such as Pyrex), it’s a durable type of glass that is workable at higher temperatures, and can withstand higher temperatures in finished form.
Soda-Lime Glass – Also called Soft Glass. The most common type of glass, it is softer and easier to work than borosilicate glass, but is more fragile.
Dichroic Glass – Glass which appears to be different colors depending on if light is showing through it vs. reflecting off if it.
Layered Glass – Glass which contains layers of different colors. Glass artists often use acid etching, engraving, or carving to reveal different color layers.
Cane – A rod glass formed by pulling and stretching molten glass from both ends. Usually canes are colored glass, and may be simple single color, or contain many colors in a pattern.
Bar Color – Hard bars of solid glass color.
Blank – A cooled glass object to used as part of a larger glass piece, or that requires further forming.
Button – A small, generally clear bit of molten glass placed on the working end of a glass piece to help secure the piece to the blowpipe.
Frit – Glass color in ground or powdered form. Frit fuses into molten glass when the molten glass is rolled through it, spreading color through the glass. Different sizes of frit can be used to create smooth color (fine frit) or mottled color (coarse frit).
Gather – The mass of glass on the end of the blowpipe at the beginning of the glassblowing process. Gather is also a verb, describing the process of placing the blowpipe into the mass of molten glass in the furnace and twirling it to attach the molten glass to the pipe.
Leaf – Also called foil, leaf is a thin metal foil that can be applied to the exterior of glass. Common leaf colors are copper, gold, and silver.
Flux – A substance used to lower the melting temperature of another substance. Flux is used in a batch to facilitate the fusing of silica when melting silica into glass.
Knurling – A band or bead of glass wrapped around a larger object.