Firing Guide FAHRENHEIT (need Celsius?) Download this Document
Firing Schedule: Guidelines for firing projects up to 3/8-inch thick.
Slumping Schedule:  
THICK Firing Schedules: Guidelines for firing THICK projects ranging from 1/2-inch to 2-inches thick
Forming
Chart:		 Forming stages, definitions, and temperatures for firing System 96 products.
Bubble Squeeze: Adding a stage during firing to reduce or eliminate bubbles
4-Segment Firing: How to easily adapt our 6-segment programs to 4-segment controllers



These are some guidelines for kilnforming projects of common thicknesses. Click here for information on firing
thicker projects. These are not strict rules, of course. Times and temperatures may vary with equipment.

Firing Chart (For projects up to 3/8" thick)
Segment Rate Temp Hold
(°F per Hour) °F (minutes)
1. Heating I: 300 1150 30
Moderate ramp up then hold to allow soft glass to settle. Soak even longer to reduce bubbles.
here is data
2. Heating II: 200 1370 20
Slow ramp to squeeze out trapped air.
here is data
3. Heat to Forming Stage: 400 See Forming Chart Desired Effect
Heat glass to forming temperature. Consult Forming Chart.
here is data
4. Anneal I: 9999 950 60
Fast ramp down then hold to thoroughly equalize temperatures.
here is data
5. Anneal II: 150 800 10
Slow cool through sensitive zone, then hold to equalize.
here is data
6. Cool Down: 300 100 0
Moderate ramp down to minimize thermal shock.

Slumping Chart (For projects up to 3/8" thick)
Segment Rate Temp Hold
(°F per Hour) °F (minutes)
1. Heating I: 150 300 15
Slow ramp up to 300º then hold to equalize temperature of
everything in kiln (minimizes thermal shock).
here is data
2. Heating II: 300 1100 20
Moderate ramp to 1100 and hold.
here is data
3. Heat to Forming Stage: 150 See Forming Chart Desired Effect
Heat glass to forming temperature. Consult Forming Chart.
here is data
4. Anneal I: 400 950 60
Moderate ramp down then hold to thoroughly equalize
temperatures.
here is data
5. Anneal II: 150 800 10
Slow cool through sensitive zone, then hold to equalize.
here is data
6. Cool Down: 300 100 0
Moderate ramp down to minimize thermal shock.

 

Forming Chart Definition Forming Temp
Slump Glass softens and slumps to take the shape of a selected form or mold. Note: small molds may need higher temperatures and/or hold times. 1215º-1250º F
Tack Fuse Separate glass layers are fused together with little deformation beyond softening of edges. 1350º- 1370º F
Contour Fuse Separate glass layers are fused together, edges are soft and rounded, project surface retains the degree of dimesion desired by the artist (any degree beyond Tack but not yet Full fused). 1400º-1450º F
Full Fuse Separate glass layers are completely fused into a single uniform layer, top surface is smooth and void of dimension or relief. 1460º-1480º F

 

4-Segment Firing
For faster firing: you may wish to accelerate or simplify firing for small or less consequential projects. If so, in the Fusing Chart, eliminate segments 2 and 6. In the Slumping Chart, eliminate segments 1 and 6.


Bubble Squeeze To Reduce Bubbles Between Glass Layers

To reduce bubbles between glass layers, fire to encourage a very slow relaxing of the layers, “squeezing” air outward to the edges for release. As the fusing chart indicates, we recommend a lengthy hold at about 1150º F, then a slow ramp up to 1370º F. Increase the effectiveness of your “squeeze” by lengthening your Hold in Segment I and slowing your Rate in Segment 2.

Bubbles are best avoided in the design stage. Large areas of uninterrupted layering invite them. For example, a 10 x 10-inch sheet atop another 10 x 10-inch sheet leaves no easy avenue of escape for the air between glass layers. Alternately, a 10 x 10-inch sheet topped with four 5 x 5-inch pieces provides seams to vent trapped air. Design to avoid bubbles for the best prevention.
© 2008 Spectrum Glass Company, Inc. PO Box 646 Woodinville, WA 98072 USA Phone: 425-483-6699 Fax: 425-483-9007 E-mail: Hotglass@ System 96.com

All rights reserved. Spectrum, Waterglass, Artíque and System 96 are registered trademarks of Spectrum Glass Company, Inc. Baroque is a trademark of Spectrum Glass Company.