[ATM] Polishing--comments appreciated

[r.gm at muhlon.com (Rodney Mayes)]

----- Original Message ----- 
From: "Rodney Mayes" <r.gm@muhlon.com>
To: <ATM@Shore.net>
Sent: Monday, January 19, 2004 5:41 PM
Subject: Bullseye during polishing--comments appreciated


 I am happy to say that my first mirror is beginning to take a polish.
First
couple of polishing sessions did not seem to do much.  So, I opened up the
channels in the lap a little more, and used the razor blade to "cut" facets
in the lap as described on the Stellafane ATM Pages.  What a difference
those little facets make. I made twice the progress in one day than in the
previous two sessions combined.  The mirror is now beginning to cast a
reflection, although I have a ways to go yet.

 I would appreciate any comments you might have on this subject:  before I
cut the facets polishing was very, very, slow.  The mirror was polishing
from center outward, but ever so slightly.  After faceting the lap, the
mirror really started to take a polish.  But, a funny thing is happening.
Now, the outer 50% of the mirror is polishing  nicely and the center is
still coming along slowly.  Also, if one looks very closely at an angle,
there appears to be a hazy (slightly less polished) ring at the 50% area
toward center, then a less hazy (better polished) area in the center of the
mirror.  This almost reminds me of a bullseye shape.  Would you say that
this is a concern, or just an anomaly that will cure itself after a good lap
press and polishing session?  I have read that
unpolished mirrors can take strange shapes during polishing.

 I will say this:  I will never try to use a lap again without facets.
Channeling a lap is not enough.  I know, I should have listened.  Any
comments appreciated.  Thanks in advance.  Rodney.