Re: ATM beginner tool questions

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

I have found that the minimum size for a tile is 1/2 of the original size,
cut in a diagonal path.  Also that tiles that aren't fully captured by the
dental stone will eventually have problems as the tiles are captured in the
stone by mechanical means and when you allow the tile to move somewhere, it
will and thus come loose.
BTW, the site is fairly nice telling of grinding a mirror.  Starting at 60
grit for a small mirror like that is pretty much going overboard.  I usually
start something that small with 120 grit as this allows better control of
the surface shape.   I wouldn't use 60 grit on anything smaller than a 16"
mirror.  In addition, pressure on the mirror makes the grind go faster
although the wets are much shorter as everything goes faster.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net