Stress tester for glass?

[jenjeant]

Hi all,

Is there a tool that tests the stress in glass? If so, where could I buy one? I just want some extra assurance that my glass is solid after annealing.

Thanks for any tips!

[Meerkat]

You want a polariscope, many places sell them and you can make your own.

[Thomas Grimmett]

There are a couple tools available for testing glass for stress... one of which is a polariscope. A polariscope will show you if stress is present or not. If you wish to measure the stress in the glass, a polarimeter will allow you to caluculate the stress in psi at any point of interest.

These tools are limiting though as far as finding stress in a finished "piece" of art. Because of the contours and colors of your piece, the polarized light will refract at different angles making you think you see stress when there really isn't or vice versa. You can, however, test your annealing cycle with a flat piece of glass that is as thick as the thickest part of your piece... or a little bigger to be on the safe side.

You can build your own polariscope w/ parts from Edmund Scientific, or get one already assembled from Nortel Manufacturing Ltd.

[jenjeant]

Thank you both so much for your replies. This is really helpful and exactly the kind of information I was hoping to get!

[ShttrdSpctrm]

you could also follow certain specifications for annealing. or you could just sell it and hope it breaks so you can sell another one.