Re: ATM : Hole in the middle

[spooner@page.az.net (Michael Spooner)]

Forget about plugging the hole - it's a waste of time. Just move the lap
around on the mirror as you press it (you don't still cold press I
hope!) <GRIN> This pluging the hole is one area the old books were just
flat wrong about IMHO. Cold pressing may have been advantageous for
plate glass where local heating from the lap could cause enough
expansion to make figuring difficult (this is mostly conjecture though
as I've only made one plate glass mirror) but Pyrex and especially low
expansion substrates are not as prone problems from quick hot pressing
just prior to use. 

Mike Spooner