Re: [ATM] pitch too stuck

["Bob May" <rmay@nethere.com>]

Looks like nobody has eplied to this pst so I will, even tho
late.
Look through the mirror and see if there is the "wet" lookinbg
contact between the mirror and the pitcch.  If so, you're going
to have to either heat the lap and mirror to get it apart or, if
there is only a small spot of adheason, you can often hit the
tool and get the pitch to shatter at that spot.  I wouldn't try
anything over about a eightth inch spot size doing an impact tho.
If there is no wet looking spot, put the two in cold water and
leave for a bit.  The cold water hardens the pitch up a bit and
the differential in temp will cause stresses that will tend to
make the two come apart.  In addition, you can do like several of
the books recommend which is to take a parallel wood clamp and
put side pressure on the tool and mirror.  Immersion in water
will cause the adhesion of the two pieces to get so low that the
clamp will easily break them apart.
Don't worry about the lap being bad after a few small chips are
taken out of it in the middle but rather warm the lap up a bit
and then do a  warm pressing with more CEO (with some dishwashing
soap includeed in the water to promot4e sliding of the lap on the
mirror) and start working the mirror immediately.  Laps do not
need to be perfect, just good enough to mostly engage the glass
when you start.  I do recommend that any persistant failure of
the lap and glass to fully mate, usually the failure is in a side
of the lap to not mate, meaning that there is a rocking between
one side of the lap and the other, as any of a failure to mate
lie this will cause problems with the polishing.  I don't mind
bubbles in the interior as long as they aren't large and aren't
centered on the lap, either of which will cause zones.
Bob May
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