From: "Russell Jocoy" 
To: dbates59{at}yahoo.com, atm{at}shore.net
Reply-To: "Russell Jocoy" 






>From: Don Bates 
>Reply-To: Don Bates 
>To: atm{at}shore.net
>Subject: ATM Tool Damage - Can it still work?
>Date: Thu, 20 Feb 2003 07:28:48 -0800 (PST)
>
>
>Help! After a very frustrating and lengthy polishing
>session on my 10" f6.6 plate glass primary, I have
>decided to drop back and punt to fine grinding. There
>are several long scratches on the mirror, and the
>center never polished out properly due to poor center
>contact with a hard lap. After scraping all the pitch
>off the back of the original plaster-based grinding
>tool, I discovered to my horror that one of the edges
>of the plaster surface had buckled, cracking one of
>the 1"x 1" tiles. I think I can repair it by pressing
>with a clamp and using epoxy to mend the crack. But
>here are my questions:
>
>1) Will the altered surface of the tool damage my
>mirror during a final re-grind with 25 and 5 micron
>emery? I think I can get it close to the original
>shape, but I'm sure there will be a slight difference
>from the original curve.
>
>2) If the cracked tile creates a defect in the mirror
>surface, can it be corrected during polishing?
>
>Thanks for any insight you can provide!
>
>Don
>
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("atm{at}shore.net")

Don,       I went through this problem but at an earlier stage... (at 25
micron)..  My advice would be to
pop the tile off and grid any sharp edges in the area. You will then
continue to grind as if the tile was still there, always rotating the tool
and mirror. .... Your mirror will not know the difference, if you glue
the tile back on no matter how acurate you are in placement your mirror
will know.... thats not good...
                                                               RUSS JOCOY
("atm{at}shore.net")

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