Stephani Stephenson on thu 25 oct 01
Cheryl
the proportions depend on what type of plaster you are using.
water to plaster ratio or 'consistency' is expressed in parts of water
per 100 parts of plaster by weight.
If you are using #1 pottery plaster, that ratio is 70 , (though it can
be between 65-75.)
Read this number as 70 pounds water to 100 pounds plaster
another way to look at the ratio is for every pound of water, use 1 lb.
7 oz of plaster, for that particular consistency.
Other consistencies are
Puritan pottery plaster 64
duramold or premier moulding 60
hydrocal is 40 -45
and a pint's a pound the world around (as in volume to weight conversion
of water, not the price of beer in Britain)
For more info I highly recommend Donald Frith's book, Moldmaking for
Ceramics.
In fact that book was recommended to me by someone on CLAYART and it was
well worth it.
Stephani Stephenson
Carlsbad CA
steph@alchemiestudo.com
mudmistress@earthlink.net
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