Spectrum now has a broad line of specially formulated "Tested Compatible" glass for hot
glass artists. These products have been Expansion-Matched to a normal C.O.E. of 96, then factory-tested for fusing comparability. Each glass has been carefully formulated for Multi-Fire devitrification resistance, and
every sheet is clearly marked with a Spectrum "Tested Compatible" label. Though they may look the same as our stained glass products, Spectrum "Tested Compatible" glasses are fundamentally different in their basic
chemistries, designed to deliver an excellent working range and superior stability for glass fusing, slumping and other Hot-Glass pursuits.Why 96?
Like many glassmakers, Spectrum chose the "96" Expansion
because of the flexibility it allows to create glasses with "friendly" forming characteristics. The most desirable products in the glass blowing community (like Glasma 71 & Spruce Pine Batch and virtually all
Kugler, & Q-Color color bars) hover around the "96" Expansion for the same reasons. These glasses are said to have a "longer working range". To blowers and other manipulators of hot glass, this means more time in
that "sweet spot" of temperatures where the artist can affect the glass. A "longer" glass offers more tolerance and freedom for creativity. Glass fusers will discover a wider range of temperatures between
"not-yet-fused" and "beyond-full-fused", thus greater freedom in forming and a wider margin of error.
Should I Still Test?
We think testing is a good idea, and will continue to recommend it. Testing is your
best teacher. You'll discover subtle nuances in different glasses, monitor color shifts, and be better able to predict various characteristics that may result from the fusing process. Plus, because Spectrum's equipment
and procedures differ from yours, you just might uncover a set of circumstances in which Spectrum's "Tested Compatible" glasses don't "work" in your system of variables. Better to discover that in testing than in a
disappointing project.
Using Spectrum "Stained Glass" Products in Hot-Glass Work
Spectrum makes a tremendous selection of stained glass products that fall outside of their "Tested Compatible" program. As
always, Spectrum will endeavor to manufacture those products around the "96" C.O.E. But, outside of System 96, non-compatible glass will not be segregated from compatible glass, so testing is a must. And, in Spectrum's
non-System 96 products, devitrification must be dealt with by using Spectrum's clear "Fusing Standard" (#100SFS) as a "cap", or by use of an overglaze, or by careful management of the contributing variables in the
fusing process.
Many glass users have had great success using Spectrum Stained Glass products for Hot-Glass work. But be aware that both stress and devitrification, even if not immediately apparent in your finished
projects, can cause cracking or surface crystallization over time. So please, when fusing with non-labeled Spectrum products, test habitually and take careful measures to control devitrification. May be mixed with
Bullseye & Uroboros 90 COE glass for quantity discounts. Spectrum 96 may also be mixed with itself for quantity discounts.
May be mixed with all Bullseye and Uroboros sheet glass for quantity discounts.
Sheet size 24" x 24" and 24" x 48".
