[ATM] Use of laminated Glass for a mirror

["Richard Brodie" <richardbrodie@optusnet.com.au>]

Hi list and experienced ATMs,
 
I saw a couple of posts in the archives suggesting it is a bad idea to
laminate sheets of glass to make a thicker blank, but can some-one
explain why? 
I would think that as long as the thickness of the top sheet is enough
to support the sagita, then if would work OK. Eg 2 x 12mm sheets to make
a 24mm blank for a mirror around 14"-16"
 
A second question : I am currently building 8" dob using 3 points to
support a 1" thick mirror.  I intend to glue mirror to the 3 points and
am wondering what the ideal diameter of glue contact area should be?
 
Thanks 
 
Richard
_______________________________________________
ATM mailing list http://www.atmlist.net/