Is Bullseye glass compatible in all conditions?
When kilnforming, there are a multitude of variables to keep in mind. If you plan to subject Bullseye glass to unusual working conditions, we always recommend conducting your own tests.
Under normal working conditions, Bullseye glasses are known for reliable compatibility. Each batch of glass we produce in our factory is tested by firing to 1500 degrees Fahrenheit followed by a fifteen minute anneal soak; the batch is then checked for stress through polarized light. If a given batch doesn’t meet our standards of compatibility, we won’t label it as such.
Up to 1500 degrees Fahrenheit and followed with a fifteen minute anneal soak, Bullseye glasses can be expected to remain stable. If you plan on using a heat process with an extremely high temperature or unusually long firing time, we recommend conducting your own tests beforehand.
Also, be aware that if you use flameworked elements, those elements may have been heated beyond 1500 degrees Fahrenheit. Those elements should also be tested separately beforehand.
For more information, please read What to Expect from Bullseye Glass.