Re: [ATM] First Timer Polishing Questions

[Mark Holm <mdholm@telerama.com>]

Bob May wrote:

> The thing with the pits that are left when a piece of glass isn't
> fully polished out is that they will be bright and flashy as the
> light beam goes across them.  The microripple is much smaller
> than the light beam so those reflections will be a lot more even
> in their intensity.

Bob is of course correct here and his answer gets at the decision you
are trying to make much better than a comparison with other polished
objects whether or not they are well polished.  (Why didn't I think of
that.)

The point to the laser test is to look for remaining pits after your
unaided eyes have reached their limit of detection.  As Bob says, you
are looking for scattered sparklies.  There may be quite a few of them,
but they are few enough that they don't form a visible haze anymore.
Aluminizing or silvering also has a way of showing up remaining pits all
too well :(

Mark Holm
mdholm@telerama.com


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