ATM Annealing Pyrex

["Tim Walters" <trwalters@hotmail.com>]

Hi All,

I just spoke at length with a gentleman in Atlanta that's been producing 
laboratory glassware (Pyrex) for close to 40 years. He says the way he 
anneals Pyrex is to bring it up to 600 C and let it "soak" FOR 10 
MINUTES and let it cool off gradually FOR 3 HOURS. I always assumed it 
took days/weeks to anneal "stuff". He checks all his glassware with a 
polarimeter and he says -NO- stress is evident.

He also said that he gets his Pyrex @ $1.15-$1.50 per square inch and 
can get 2 foot square pieces @ 1 1/4" thick from an outfit called 
Cincinnati Gasket.

Now for the questions:

1) Do you anneal Pyrex before or after you grind it?

2) Which would you rather make/have?:
    a) 14" dia., 1 1/2" thick mirror
    b) 16" dia., 1 1/4" thick mirror
-and why-.....

There's gonna be a quiz...

Thanks for any input,

Tim Walters
trwalters@hotmail.com
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