Re: [ATM] Grit for 10" Quartz Blank - 3 questions

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

Don't bother to put any cement into the cat food tin although it
will wear a lot during the initial grinding.  Just a waste of
time and materials.  If you've got an old grinding wheel around,
that will even work well.  It is just the ege that you need as
the center only makes contact when you first start.  The
principal of where you grind is where you remove material is
predominent here and the edges of the tool are the only part that
will contact the glass after a few minutes of grinding anyway.
The tiles inside the can will have little effect as they are
going to be so much softer than the metal.
In truth, any old piece of steel, brass copper, zamac or other
such metal will do a fine job if it is basically round.  One
mirror got done with an old bronze gear that the guy had laying
around after he repaired his outboard motor and it did an
excellent job, being about  three inches in diameter.  Things
like teeth on the face only help the grinding by increasing the
local pressure to chip away the glass and since they were all
around the tool, things were fine.
I haven't seen it done with a cat food tin yet but I'll suspect
taht there won't be much left of the tin by the end of grinding
as there just isn't that much metal in a tinn.
So remember, grind mostly in there center area, I use circular
strokes rather than a back and forth, and leave the edge alone
until you are near the desired depth.  At that point, doing rings
around the edge area evens that out to where you have a fair
cspherical shape.  At this time you pour the tile tool and finish
up making the hole you have made spherical as the grit allows.
Bob May
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