Re: Simple, Inexpensive Refractometer to Test Large Glass Blank

On Jul 31, 3:48 pm, Uncle Al <Uncle...@xxxxxxxxxxxxx> wrote:
"W. Watson" wrote:

I have a clear lens blank about 20" in diameter and 1.25" thick. I'd like to
determine the type of glass. Where can I find a device as per Subject?

Cargil refractive index fluids.

Shine a laser pointer in from the side until you hit the critical
angle at the face. A little recursion ought to zoom in on it. Or do
it two-variable by measuring critical angle against air and with a
layer of water on the face. One incoming deviation, two outgoing
deviations, determined solution.

--
Uncle Alhttp://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)http://www.mazepath.com/uncleal/lajos.htm#a2

Al, great response as usual. Wish I had first thought of it first.

Harry C.


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