To: ATM{at}shore.net
From: Robert Fifarek 
Reply-To: Robert Fifarek 


Hello ATM;
I've been pushin glass on the same 16", 1" thick plate glass
mirror for almost two years. Finally completed making pitch lap. Had great
success with all stages of grinding. Within first hour of polishing after
cleaning mirror off, WHAT!!!! a nice 2" long scratch appearing to be
deeper than the last stage of grinding which was 9 micron WAO. Now the
pitch used was Gugolz 73, and had some problems trimming and making where
some pinch ended up on the side of the pitch base. Pitch base is concrete,
but was sealed thoroughly with polyester resin and fiberglass cloth way
before the pitch was poured. But being as hard as it is I can't rule out
that small pieces of pitch may have gotten between the mirror and pitch
lap. What gives? Is the pitch capable of causing such a thing ? or should I
fess up and admit I might have been sloppy somewhere and some foreign
particle invaded my polishing operation! Next question, should I take a
step back and fine grind for a while or will noticeable scratches to naked
eye polish out?

Rob in Ramona

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