From: "Bill T." 
To: atm{at}shore.net
Reply-To: "Bill T." 


Congrats on your progress.  If you can't see the scratches at 10x, then
they will certainly polish out.  Your 5 micron may not be contaminated.
Scratches like that are common below 9 microns, and are a good reason to
stop at 9 microns.

FWIW, I stopped getting scratches about the time that I stopped being
obsessive about cleanup.  Feverish cleanup activity can spread
contamination very effectively.  Grits don't have feet, but they're good
hitchhikers - never give them a ride.  I have polished many mirrors with
chunks of 220 grit visible on or near the floor with no problems.

Bill T.



>Hi all,
>Just an update.  I just finished the 5 micron grinding.  Finish on mirror
>visibly is great.  10x magnifying glass shows even matt surface.  Red test
>shows evenly ground surface.  Only problem is that during the 5 micron
>stage
>I picked up a few micro scratches.  Not visible under the 10x loop and
>certainly not visible to the naked eye, but I know they will show up in the
>coating if polishing doesn't remove them.
>I am not sure where they came from.  I have been fastidious about keeping
>everything clean.  New towel and sponge at the beginning of each grit.
>Scrubbed bucket at end of each grit several times and flushed with clean
>water at least three times before starting next grit.  Tile tool was washed
>between each grit with high pressure hose. Work surface was scrubbed
>between
>each grit with new mat under mirror each grit. Mirror washed between each
>grit, twice, changing water in bucket between and after washing.
>I can only surmise that my WAO 5 grit is contaminated.  I know that these
>micro scratches won't affect the performance of this mirror, but I was
>hoping to produce a mirror with no micro scratches.
>I can easily go back to 9, 15 or even 25 grit, but I still am left with the
>contaminated 5 grit.
>I am going to make my pitch lap tool tomorrow while I ponder how to
>proceed.
>Can anyone tell me where to buy uncontaminated WAO 5 or equivalent??
>Clear skies, Jerry
>
>


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