Re: [ATM] Polishing and a red laser

["Mitchell R" <funnybone101@embarqmail.com>]

I looked at the surface with a red laser this evening. I was dismayed to
find that a substantial amount of the light was reflected by the first
surface rather than passing through. It seems to illuminate very small pits.
I looked at other surfaces that I have made and found the same to be true
with them, although they aluminized very well (I had subsequently removed
the aluminum as it had become quite dirty from sitting around and I wanted
to recoat them).

Does anyone have any experience with using a laser to ascertain the state of
polish on a mirror substrate? I'd like to hear your thoughts.

Thank you.

Francis J. O'Reilly 

Well I've learned a few things about the laser test.

1. It will show blatantly on the surface if you're not fully polished out.
2. If you want to be really picky do it in a dim/dark room.
3. Even an extremely well polished surface with reflect a tiny amount but
that's no excuse for under done polishing. You can usually tell because the
edge will be brighter. Even in the dark if the mirror is clean it is almost
not there.

On my 10" I found after pushing for 10 hours *REALLY* hard (letting the mix
dry up a bit so friction really, really picked up, good contact, etc) I was
almost totally polished out. I called it done after 11, but there was the
slightest improvement noticeable up until 12.5 hours. Then it was basically
not visible.

Mitch 

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