Re: ATM Rock Hard Pitch Lap

["Arjan te Marvelde (ELN)" <Arjan.te.Marvelde@eln.ericsson.se>]

<<
it) off.  I read in the archives that it may be possible to brush turpintine 
on the lap and let it sit overnight.  Will this work?  Thanks for any 
assistance you can offer.
>>

I have done this on a lap that had hardened, but this lap was not hard when poured. It did work very well for me. What happens is that the upper layer (~0.1mm) of pitch is diluted and softened somewhat, and will more easily conform to the mirror during the polish. There is a limit however, in the amount deformation it can handle.

Don't apply too much turpentine at a time, cause it will make the surface sort of fluid. It will then stick to the glass, esp. if you don't apply plenty CeO when pressing. Also some bits of pitch may scrape off, but this is OK if it is not a lot. Maybe if your lap is extremely hard it pays to apply multiple thin layers of turps instead of one thick, and let it take a week or so to stabilize.

In any case: it won't harm to try! You can always make a new lap, and get the pitch of the glass with some more turpentine.

Hope this helps...
 ... Arjan te Marvelde