: Boeing outlet store, where they had a roll of satin weave glass cloth. It
: was pretty cheap by the pound and I bought a lot of it. I'm sure that the
: project list will expand to accomodate it, but I'd like to know just what
: it is that I have. I can easily weigh a fixed amount to get that
: information, but can anyone tell me how to tell the difference between
: s-glass and e-glass?

If you can find some known glass of the same weight and weave, do a test panel with each. If it breaks the same, you know what it is. If your known glass was E-glass, and the unknown stuff breaks with more difficulty, it's probably S-glass. S-glass is about 20% stronger.

If it's from Boeing, I'd bet S-glass.

Shawn