Fredrick Paget on thu 29 apr 10
I prefer to make plaster slump molds. I do it by spinning liquid
plaster in a suitable container on my potter's wheel while it sets
up. I can get any sort of parabolic curve i want by choosing the
rotational speed.
If you want to try this, experiment with just plain water until you
are comfortable. It is very easy to sling the liquid over the rim and
all over the surroudings. Try it outside as plaster slung all over
your studio is not nice.
This is a pretty well known artifice - there have been telescope
mirrors made this way. The interaction of gravity and centrifugal
force cause the liquid in a spinning container to assume a surface
that is a true parabola.
I have a big tub from the hardware store that can make a 2 footer.
Weigh the plaster to the proper powder to water ratio for pottery
plaster and mix it and you have a nice liquid mix that won't set up
too fast if you use cool water.
--
Fred Paget
Twin Dragon Studio
Mill Valley, CA, USA
fredrick@well.com>
Charter Member Potters Council
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