Re: [ATM] Polishing questions - stop polishing, keep polishing, or go back to fine grinding?

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

Polishing kind of depends upon several different things.  If you
use too much or too little CeO, you won't polish as fast.  If the
lap isn't in good contact with the glass, you will again have
problems.  If you go too slow, again, slow polishing.
When you do polishing, you should have a fair bit of resistance
to movement by the mirror to lap contact and this should be a
viscous type resistance to movement.  If the mirror just slides
over the lap then you aren't doing any work.  You should be
needing to apply at least 20lb. of force to move the lap on a 6"
mirror if the lap is in good contact.  Needing to only do about
1lb. of force is basically just the mirror sliding over the lap
on a film of water and/or CeO.
If the mirorr is covered all over with CeO then you're using way
too much of it.  I like to see a light dusting of CeO left behind
by the lap when a mirror comes off the side of a lap for best
results.
For the pits, if you see a bunch of what you think are pits, wipe
them with the edge of your clean and dry finger very lightly and
see if they move or disappear.  If not then you're not quite done
yet.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

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