This past weekend, I picked up a Fused Silica blank at Stellaphane. I was wondering if anyone had experience grinding and polishing Fused Silica. How does it compare to making Pyrex mirrors?
The dimensions of the blank are diameter 7.75" and thickness 1.57". I got an great deal! Newport lists an 8" blank for $540, I paid $45! Fused Silica has a crystalline latice structure with a coefficient of thermal expansion equal to 5.5x10^-7/C. Thats about 1/6 the coefficient of Pyrex which makes it a very stable material for optical components.
I plan to construct an f/6.5 instrument with baffled tubing. To reduce the number of baffles, I will need to use an oversized tube with an ID of 10.5-11.5". Unfortunately, I have only found suppliers for tubing in the range of 9.5-10" ID and 11.875-12". Does anyone know of a source for 10.5"-11.5" tubing? Preferably aluminium.
Thanks, Tal Schwartz Tal@Johnson.Cornell.EDU