James F on sat 27 sep 08
Shula...
The folks at US Gypsum said that if the plaster gets over 120 degrees F (af=
ter or during curing)=2C then the plaster form becomes 'killed' (their tech=
nical term) and loses it's absorbent properties. This=2C according to them=
=2C renders it unfit for slip casting=2C though it would likely still be pe=
rfectly serviceable for hump or slump molding of slabs and such. If the pl=
aster form gets very hot=2C it will=2C as Ivor said=2C become crumbly again=
. When you cast glass or metal in a plaster mould=2C the plaster crumbles =
right off. The bottom line seems to be that as long as you are not slipcas=
ting you have much more leeway.
Be well.
...James
> Date: Fri=2C 26 Sep 2008 16:15:00 -0700
> From: purplelama@EARTHLINK.NET
> Subject: Re: Plaster
> To: CLAYART@LSV.CERAMICS.ORG
>=20
> Several people have mentioned that the temperature shouldn't go above 120=
. Is that only when the plaster is curing? May I assume that it won't harm =
the plaster if the temp goes over 120 once it is cured? Why do I ask? I liv=
e in the desert where the temp in my garagio has been known to get over 120=
!
>=20
> Thanks
>=20
> Shula
> Desert Hot Springs=2C California USA
>=20
> -----Original Message-----
> >From: Fredrick Paget
>=20
> >
> >If you can put it out in the sun it will dry in a few days and that
> >won't hurt it unless it gets over 120 degrees F .
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