Tested Compatible Glass

Why do they have to mark glass "Tested Compatible Glass? Why can’t they just make all glass the same and eliminate this part of the process?

I guess if glass was just made by one company and only one way this would be the deal. But, it is made by various companies and made differently at each site. Yes, all glass is not created equal, nor can it be fused together.

Even though some glass may look the same as stained glass, or fused glass products, you can’t tell if they are compatible by looking. There are numerous manufactures, and just as many techniques for making glass. They are different in the basic chemistries, and are designed to deliver an excellent working range and stability for glass fusing or slumping. There are also many different coatings that are applied to glass.

This indicates that the glass has had its expansion matched to a specific C.O.E. These glass products are factory tested for being compatible for fusing. Manufacturers do charge more for this glass, because of testing and assuring the results.

You will even notice that a particular manufacturer will not guarantee their product with another manufacturer’s product, even if they have the same C.O.E. They will tell you that they do not recommend mixing products from outside their program. If you want great results in your glass fusing experience, know your glass. Stick with one C.O.E and one manufacturer.

Look for stickers that guarantee the glass has been tested. The sticker should indicate that it tested compatible glass. Most glass will carry the manufacturer’s identifying label. If in doubt, ask what the C.O.E.of the glass before making your purchase.

If in doubt about the C.O.E. of a product, then test. Testing is your best teacher, and it will enable you to discover different color shifts, or other characteristics that might happen during the fusing process. It would be to your advantage to find out the C.O.E. during testing, than ruin a desired project.

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