Originally Posted by Someonenameddavid
i hate to post this URL because people who go there spend hours and dollars buying the weirdest stuff... but they have good prices and service:
has a 15x9 inch optical flat for $5 which you could make into a ground glass screen using jeweler's rouge
but look at all the other stuff too....
1/4" thick would be very impractical it's more normal to use 2mm or even 1.5mm but never 6.35mm.
My APUG portfolio