Re: [ATM] Glass Blank Question

["Jason Lehmann" <jtravel@bellsouth.net>]

Thanks guys for responding so quickly.

 

Guy, 

I will take the CTE info under advisement if I end up making a mirror out of
it.  I looked at the blank for bubbles and I didn't see any.  I then took my
lcd monitor and used it along with a 35mm camera polarizer and checked for
strain.  The test showed very good results but until I have a polarizer that
is the full size of the blank I won't know for sure.  Does a tempered glass
disk look like the rear window of cars with polarized sunglasses?  

 

Richard,

I found one web site that said the Crown family had densities between 2.5 to
2.7 g/cm3 and therefore I assumed that it was a type of Crown glass.  I
don't have much experience with identifying types of glass so your
information is helpful.  You mentioned it could be Crown-Flint.  The blank's
vintage is probably at least 10 to 15 years old and maybe older.  Also,
under closer inspection the blank has Crown-Flint inscribed on it.  I wonder
if this helps identify it a bit better.  What test can I do at home that
might be able to help me nail it down?

 

Jerry,

I agree with you and am happy to have the glass in hand.  I wasn't too
worried if it was the best but I wanted to make sure I wouldn't get myself
into trouble!  I would also like to see if a "common" mirror would
underutilizing the glass.  If it turns out to be useful for a refractor atm
then I would consider a trade of glass.

 

Jason

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