Re: u-wave oven: I just MELTED a frickkn BEER BOTTLE

>    I'd recommend staying away from pyrex; as you likely
> know, it's "tempered" by allowing the surface to harden
> faster than the inside so stresses are contained which gives
> it its heat-resistance and comparative shatter-resistance.
> Change that and your "tink" event will pale by comparison.
> OTOH I wonder if that makes the melting-pyrex stories more
> believable as the interface might be a better absorber.

Pyrex handles heat by virtue of the low expansion with heat. It doesn't need
to be tempered and tempering wouldn't improve the ability to handle
temperature changes.

Glass can be checked for tempering or stress in general by using two
polarized sheets, one in front, the other behind. Rotate one and watch the
pattern. With tempered glass, just a pair of Polaroid sunglasses is usually
enough.

Clear Skies

Chuck Taylor
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