Re: ATM questions re: annealing mirror blanks

["Bob May" <bobmay@nethere.com>]

When you consider that the testing spec is very vague in it's quality
standard and that the annealing process is also a bit on the variable side,
it is no wonder that there is a certain vagueness to all of this.
I'll note that there is generally three grades of annealing, coarse -
basically they don't care about the annealing other than to insure that the
glass isn't tempered, fine, where it is fairly well annealed and good for
most purposes, and precision, where it is done to the customer's spec.
You could be getting in some of the glass you buy a reading that is well
within the precision spec but isn't listed as such because the test wasn't
done to that level, just that the glass was better than a certain point.
Bob May
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