Old or damaged mirror blank

[nobby2]

Looking for a mirror blank in any condition to use while testing a mirror Foucault tester.
Preferably 8" but other sizes would do. Just want anything to see if my tester is working before I buy a proper blank.

I have been using a completed (silvered) 8" GSO mirror which has to much reflection for a convincing shadow result.

[JA]

Hello Nobby,
Do you think using a piece of "non reflective" or even a fog type glass in front of your current mirror would help? The type available from glaziers for use in picture frames. It will definitely cut and ever so slightly blur the reflection. Go to a glazier and experiment using a small hand mirror on (behind) various samples. The effect will also vary with distance to the mirror, but I'd start with close up.

Best
JA