Re: ATM dental plaster - pour stone

[Mark Holm <mdholm@telerama.com>]

> However, I dislike Portland since it
> is highly toxic and will do nasty things to your skin, eyes, lungs, etc.
> 


Well, I don't think I would call it highly toxic.  It is rather alkaline, and quite dusty.

I'm sure breathing the dust isn't good for a long term thing, or if your lungs/bronchi

are easily irritated.  It will irritate the skin pretty badly, but only after a fairly

 long exposure, many minutes not seconds (unless you have quite sensitive skin). Try to

avoid dust, and if you can't, wear a dust mask and some closed goggles.  Once water is

 added, the dust is no longer an issue, but you will want tough rubber gloves if working

 by hand.  A bunch of years ago, I helped my Dad pour a small slab of concrete.  We did

all the mixing in a large tub with hand tools and all the screeding. troweling, etc.

by hand.  Afterwards, our hands were in pretty poor shape, sore and red with not a lot of

the outer layer of skin left.  Still, they healed in a couple of days with no noticeable

permanent damage.  Didn't need a manicure for a week or so.  It took off all the cuticle

around my nails as cleanly as a surgeon, and sanded them smoother than any manicurist.

Don't know whether the abrasion or the alkalinity is more damaging.

Mark Holm
mdholm@telerama.com