Re: [ATM] glass or ceramic blank?

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

Better yet is to do the smoothing before the stone is fully cured.
Once the setting has started and the stone has some firmness, you can strip
off the mold and then use a stick, knife or putty knife and plane the back
of the tool flat as you desire.  The stone is still a bit soft and doesn't
have a lot of strength but it will hold its shape with gentle handling.  I
pull the mold, leaving the tool and mirror together and flatten the backside
and when the stone has had another 10 minutes or so of setting time, I then
pull the mirror off of the tool, letting it cure for a bit more as I make
sure that the front side is clean of any excess plaster and any holes are
filled.  I then throw some grit on the tool and start grinding.
FWIW, I've seen people spend a lot more time making a lap for polishing than
what I spend making a tool for the grinding.
Bob May
bobmay@nethere.com
http://nav.to/bobmay
http://bobmay.astronomy.net

_______________________________________________
ATM mailing list http://www.atmlist.net/