How to Glass Fusing Kiln Firing Schedules - Go Fusing Blog
Contour FuseFire PolishFull FuseGlass Kiln Firing SchedulesKiln Firing SchedulesTack FuseThermal Shock

How to Glass Fusing Kiln Firing Schedules


Common Products used in Kiln Firing: Thin fire, Kiln Wash, Thicker Fiber Paper

Firing glass in a kiln is not difficult but you must make adjustments to almost all firing schedules because:

  • Every kiln is different
  • Every make of glass behaves differently in a kiln.
  • Every location adds different environmental conditions such as moisture levels, altitude, and heat or cold.

The schedules below are the most common type of fusing that are used to obtain set results. They are approximate temperature levels and will produce different effects and for COE 90 glass increase the temperatures by 10°+

Thermal Shock Range: 0 - 1000°
Once the glass is heated to above 1000° there is no longer a fear the glass will crack.

Slump: 1200°
The glass will become soft enough to sag and can be slumped or draped.

Tack Fuse: 1300°admin
When two pieces of glass are touching each other they will bond together permanently and the edges will softening.

Fire Polish: 1325°
The glass will soften and the edges will become slightly rounded.

Contour Fuse: 1350°
The glass will soften and the edges will become well rounded as the glass begins to try and smooth and level out.

Close to a Full Fuse: 1400°
The glass will become almost smooth and level.

Full Fuse: 1450°
The glass will have become molten and the layers merged into a single level.

Note: Please consider if you are slumping 1 layer of glass or 2 layers. When only slumping a single sheet, Firing results can occur faster.


  • Glass kilns with elements in the lid allow the glass to heated more evenly and can make the firing go faster.
  • Elevate a mold on kiln posts, this will allow the heat reach the bottom of the mold and firing will go faster.
  • Different Colored Glass fire at different rates. Faster to slower: Black, Clear and Opaque Whites