Re: ATM 18" mirror Progress and Dental Stone question

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

Yes- Herb is right- there is no need to worry over dental stone.I make big
tools with Portland cement/sand mix. See my earlier posting about how I
build large portland cement channelled grinding tools. I've made many, never
have had a grain of sand fallout and cause any damage.  Tools are also more
stable dimensionally. ATM's should get away from the idea that dental stone
is somehow the ideal substrate for a channelled ceramic tool. It ain't
(pardon my colloquialism). A few have written saying they've kept my rather
longish posting about how I make and use Portland cement/sand/waxxed
channelled ceramic tile tools. If any missed it, and would like a copy, I
still have it in my sent items folders and will be happy to forward it-

Clear skies to everyone-
Dave

----- Original Message -----
From: "Herb Kasler" <h.kasler@worldnet.att.net>
To: "Ken Hunter" <kb7h@onemain.com>
Cc: <atm@shore.net>
Sent: Wednesday, July 11, 2001 12:42 AM
Subject: Re: ATM 18" mirror Progress and Dental Stone question


>
> Ken,
>
> FWIW, you can make a perfectly good tool without getting dental stone. The
> folks at the Chabot workshop here in the Bay area use plain old concrete,
> sealed with marine epoxy. They've made countless mirrors with it.  I used
> something called pourstone, which is a cement for anchoring fenceposts, to
> pour the tool for my 16" mirror. I sealed it with polyester resin (the
stuff
> you get for marine fiberglass) to keep any gritty bits from escaping and
to
> adhere the tiles to the face. The stuff is just a mixture of portland
cement
> and plaster of paris. It is really, really hard. You won't be able to
break
> it unless you take a sledgehammer to it or drop it off a 5-story building.
> It also resists moisture quite well, though the sealing makes that a moot
> point. I had no problems with it whatsoever.  I bet you can get it at just
> about any hardware store in Australia, and it's a lot cheaper than dental
> stone, too. I paid $20 for enough to make my 16" tool. You might have to
buy
> another $5 worth to make your 18"er. In the time it would take you to get
> your dental stone, you could be done grinding.
> Later,
> Herb.
>
>