IMPORTANT: The most important thing when working with glass is to make sure the glass is compatible with the project you are working on. Glass is rated off of a Coefficient of Expansion (C.O.E.) rating. This rating is given to glass based on how it expands and contracts. Therefore, you cannot fuse glasses with differing C.O.E. rates together or it will break!

The world of glass is a beautiful form of art. Creators make sculptures bowls and other magnificent and unique pieces detailing the vision of their artistic mind. Glass kilns are perfect for all your glass projects. Most glass projects need temperatures to go up to 1700F with many processes being done at lower temps. Hot Shot Ovens can achieve all of the processes of annealing, fusing, slumping and casting in order to turn your idea into a beautiful piece of art.

  • ANNEALING: Annealing is the process of slowly cooling glass after it has been formed.  Annealing glass is typically done at roughly 950-960F°. Annealing helps the glass not to crack. It makes the molecules in the glass vibrate to get the stress out of them. This is done in bead making as well. It allows the beads to become strong and not brittle. This process takes about an hour to fully soak the glass. Soaking is a term used frequently in these processes and it means to hold the product at a certain temperature for a certain period of time.
  • FUSING: Glass fusing is simply the process of stacking two or more layers of “compatible” glass together to make a design, and then placing the stacked glass into a kiln, where it melts (fuses) together.
  • SLUMPING : The forming stage of warm glass work that allows you to shape your fused projects into beautiful and functional items by heating them just enough to bend or ‘slump’ them into ceramic/or metal forms.
    • Slumping range of most glass 1200°F to 1300°F
    • Bottle slumping is within or close to this range, but close observation is recommended as different bottles will deform at different ranges.
  • CASTING: A glass firing technique using hollow or open faced molds to contain and shape the melting glass.
    • Glass Pasting or also known as Pâte de Verre is done at 1300°F to 1400°F. This casting technique uses finely crushed glass and produces a textured or frosted surface look. 
    • Cavity or Open Face is done at 1450°F to 1700°F.  These firing temperatures for casting range significantly based on sizes and thickness of both the molds and the glass that is being used.

Some important temperatures used to make glass art:

  • 1200°F Draping – glass softens enough to bend over a mold.
  • 1250°F Slumping – glass softens enough to bend into a mold.
  • 1300°F Fire Polish – glass melts enough to produce a surface polish.
  • 1350°F Tack Fuse – pieces of glass will permanently fuse together.
  • 1450°F Full Fuse – pieces of glass will fuse and melt to a single level.

When making glass art, there are typically many steps to complete a project. For instance, when making a glass plate or bowl, the first step would be to fuse the glass into the desired design you are wanting. Once this process in fully complete, you would then either drape or slump the glass piece with the mold you are using.

Kilns can create programs that can assist in all of these steps in order to assure the glass is being fired at the right temp, but also being cooled properly in order to protect and strengthen the glass piece.