FX90 Glass Products - Compatible to Bullseye
Uroboros Glass first developed and released ‘tested compatible’ fusible glass products in this category in 1989. Since then, specialty COE and tested compatible fusing glass has become a major product category for us. We currently produce glass in 4 different COE points, each for different markets. Our original clear fusing standard for the 90COE/'Compatible to Bullseye' category was formulated and melted to precisely fit Bullseye Glass’ master standard glass. Since then, all our FX90 products are fuse tested daily to our long established 'Compatible to Bullseye' clear standard glass. This product line includes:
The Uroboros Compatibility Testing Program
We are serious about consistent quality in our tested compatible products! Our tested compatible glasses undergo the most rigorous testing in the industry. During production, every square foot of every sheet of our tested compatible glass is examined in polarized light to insure that it is free of stress or contamination, even if it’s invisible to the naked eye. After this visual test, every tenth sheet in each production run, as well as frit, stringer, noodle, and billet post production samples, are fuse tested against our Master Standard test glass. Strain in fuse tests is measured on a calibrated polariscope, as shown below. Using this system we can measure not only the precise quantity of strain, but whether the strain is in tension or compression. Only products that test within plus/minus 45 nm/cm of stress birefringence in polarized light are graded as ‘tested compatible’. This is equivalent to a maximum of plus or minus 250psi of internal stress at any glass to glass contact point, or approximately plus or minus less than ½ COE point.
Fuse test showing significant stress in a calibrated polariscope. How do we perform our fuse tests? We use and recommend the Reynolds Interface Compatibility Test (RICT). This edge-to-edge seal test provides the most accurate test results in the industry, and is a close match to the International Standards Organization’s method for measuring stress in glass to glass seals: ISO 4790. It is also described in detail in Gil Reynolds' The Fused Glass Handbook. Gil's highly useful book is available from most suppliers or from his website.
[image of prefired and post fired fuse test bars here]