Richard Aerni on thu 2 oct 97
Victor,
I'm no plaster expert, but I'll give your question a whirl. #1 Pottery
plaster is the best plaster for molds for its durability and absorptive
qualities. That is not to say that you cannot use other types for molds
as well. I would have to travel 1 1/2 hours to get hold of fresh pottery
plaster, so what I have used instead is Molding Plaster, which according
to the specs, is just 2-3% less absorptive than #1 Pottery Plaster. This
has worked for me, and I've been using some of the molds for nearly 10
years now and they're still going strong.
There was an earlier post today from John (?) Rodgers about plaster that
contained excellent advice. I would urge you to contact US Gypsum, 101
South Wacker Drive, Chicago, IL 60606, and have them send you info on
their products, as well as the slide rule type calculator. They will do
this for free, and you'll have all the info you need to do graduate work
in plaster on your own. They will send you spec sheets on each type of
plaster, and the calculator will do all the estimating and tough work
with math for you. It is the same calculator that comes in the pocket of
the Donald Frith book, except this one is free.
Good luck,
Richard Aerni
Bloomfield, NY
VICTOR JOHNSTON wrote:
>
> I've been using USG #1 casting plaster for my molds. Do you
> know what the difference is? Is potters plaster harder or softer?
> What are the advantages of potters plaster? Where would I get
> potters plaster and what would it cost? I usually buy my plaster
> 100#s at a time but could get more if need be. Right now I am
> paying $9.00 per 100# bag at a local wholesale building supply.
>
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