Re: ATM (Whack Test)Plate mirror warnings

[mike coslo <mjc5@psu.edu>]

    The idea was to test the theory that a figured plate glass mirror could lose it's figure under the stress of impact. We needed a figured mirror to do this. It would be possible to test a polished flat, but trying to test a basic hunk of glass before and after whacking would be
difficult.

    - mike -

Doug Tanaka wrote:

> >       If there were a brave soul in the group, they could try making say a 6
> >inch plate glass mirror, polish it to a sphere, then give it a walloping
> >good whack with a rubber mallet. Then test it again. That could be an
> >interesting experiment.
>
> What about hitting the plate glass before grinding begins?  It would seem to me that if there was a question as to the integrity of the glass, this would answer it before any labor was wasted.  If a bump was going to change the figure after figuring, perhaps it would do it before.
>
> Doug Tanaka