To: 
Reply-To: "Scott Berfield" 



I am at a total of 8 hours polishing and judging from the excruciatingly
slow change I am seeing (can you say asymptotic approach?) in the surface
quality, I am guessing I have at least another 6-8 hours to go.

I have seen some discussion here (and I searched the archives) about
channel-less laps pro and con. I am using a lap made with a nice rubber
mold from Kevin McCarthy - which made it VERY easy and clean to make and
which resulted in a very easy to conform lap. The pitch I was using was way
to soft, so I re-made the lap with a harder mixture. It has been working
well, but I was getting used to it changing only very slowly. We had a warm
weekend and I did an extended polish on Saturday and Sunday - putting in
about 4 hours total - and now the channels have mostly closed up. I am
getting really good fit, and the surface is looking very smooth. Do I need
to re-open the channels or can I stick with micro-facets only going
forward?

Also I checked the Ronchi patterns on Saturday after the mirror had
stabilized and the curve appears to be more oblate than before. Any
suggestions on strokes, MOT vs. TOT, etc... To get closer to a sphere? Or
does it really matter?

Finally, the Sunday session appears to have created numerous small VERY
find short scratches (sleeks?) about 3/8 - 1/2" long and hard to see
except with a light at a sharp grazing angle. I don't think there is any
contamination - did I just go too long on the wet? Any suggestions on
avoiding these? They seem very faint/shallow - can I assume they'll polish
out?

Thanks in advance.

-scott

--- BBBS/NT v4.00 MP