Re: ATM 18" mirror Progress and Dental Stone question

["David Harbour" <scarab@peakonline.com>]

Oh, yes- I almost forgot- after you pull the little matchstick spacers out
from between the tiles prior to waxing the channels, there will be little
tips of sand/portland mix at the corners, vertices, of the channels where
they come together where the ends of the matchstick spacers couldn't come
together and fill- clean these little tips of portland/sand mix out before
waxing the channels. You'll know what to do- think like a grain of sand that
is calculating how to ruin your day by getting onto the mirror when you are
grinding. If you can get into the mind of a grain of sand, you can second
guess all of its plans for causing mayhem and prevent them.

Dave

----- Original Message -----
From: "Damian Kruger" <djkruger@mpx.com.au>
To: "ATM LIST" <atm@shore.net>
Sent: Tuesday, July 10, 2001 6:37 AM
Subject: ATM 18" mirror Progress and Dental Stone question


>
> Hi List,
> Does anyone out there have a source of dental stone in Australia? I'm
about
> to pour a 18" tool after hogging out my 18 " blank to a depth of 4mm (F 7)
> by hand with a 5kg barbell weight, and 80 grit.  It's taken almost exactly
4
> hours (yes four) to get there, quite quick compared to my 2 previous
mirrors
> with glass tools.  The desired depth is 5.71mm (F 5) and so to obtain it
I'm
> going to switch to a dental stone tool so I can get the curve to the edge
> (currently 2-3" short) and get it spherical.  John Murray if your out
there
> I believe you had a source a while back.  For those who are about to
suggest
> seeing a dentist, has anyone had any luck with a sourcing from dentists?
> Price?
>
> Previous posts have indicated Dentists reluctant to sell it to people of
the
> street.  Currently I'm not chummy with any either!   For those interested
in
> the grinding logs for big mirrors I will post mine to the group (and put
it
> on a web page) at a later date so those who are contenplating grinding a
big
> one by hand  can see what they're in for.
> Regards,
>             Damian Kruger
>             Cairns   Australia
>
>
>