Joy Holdread on sat 6 mar 99
> One thing that differs in the way I teach the process is to use Crisco
> instead of petroleum jelly. It's easier to work with, better for your skin
> since it's vegetable based, and easier to clean up. Models usually comment
> on how soft their skin feels.
>
Has anyone made a plaster mold using a plaster mold? I want a negative of a
press mold. Rather than buy mold release has anyone used petroleum jelly or
Crisco on a plaster mold to make a reverse?
Joy in Tucson just aching for a week of studio time.
Bryan on sun 7 mar 99
-----Original Message-----
From: Joy Holdread
To: CLAYART@LSV.UKY.EDU
Date: Saturday, March 06, 1999 8:50 PM
Subject: Re: plaster life cast & a mold from a mold
>----------------------------Original message----------------------------
>> One thing that differs in the way I teach the process is to use Crisco
>> instead of petroleum jelly. It's easier to work with, better for your
skin
>> since it's vegetable based, and easier to clean up. Models usually
comment
>> on how soft their skin feels.
>>
>Has anyone made a plaster mold using a plaster mold? I want a negative of
a
>press mold. Rather than buy mold release has anyone used petroleum jelly
or
>Crisco on a plaster mold to make a reverse?
>Joy in Tucson just aching for a week of studio time.
Loosely speaking this is what prompted me to ask my original question. In
the discussion about plaster the recommendation was to not use petroleum
products with plaster, it plugs the pores . What works in this case?
Bryan
John Jensen on sun 7 mar 99
>press mold. Rather than buy mold release has anyone used petroleum jelly or
>Crisco on a plaster mold to make a reverse?
>
My thought here is that if you use petroleum jelly or Crico for a mould
release it will sink into the plaster and diminish or destroy it's porocity.
For that reason I suggest something water soluble. I've used Murphys oil
soap for a release in some situation and it can be washed out....Might be
worth a test.
>
>
John Jensen, mudbug@toad.net
Mudbug Pottery
Annapolis, Md.
Jan McQueary on sun 7 mar 99
If you wish to make a mold from a dry plaster original, a good tip is to
FIRST SOAK THE PLASTER ORIGINAL IN WATER UNTIL IT IS COMPLETELY
SATURATED. Take it out and dry off the surface well. Then apply your
coats of mold soap or Murpheys oil soap mixed half and half with water,
wiping off between coats, until water beads up on the surface of the
original.
If you are making a mold from freshly cast plaster, it will already be
saturated, so you can go ahead and soap the mold.
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Randall Moody on mon 8 mar 99
>Has anyone made a plaster mold using a plaster mold? I want a negative of
a
>press mold. Rather than buy mold release has anyone used petroleum jelly
or
>Crisco on a plaster mold to make a reverse?
>Joy in Tucson just aching for a week of studio time.
Yes I have but the problem with petroleum jelly is that it is hard to get
out of the mold and if you do not get it out then is acts as a moisture
barrier. This doesn't allow the plaster to draw the moisture out of the
clay. If you can find concentrated Palmolive or the like it is much easier
to work with and washes out readily.
Louis Katz on mon 8 mar 99
Hi Joy,
Yes I have used Vaseline as a release. Whenever possible I use English Crown
Mold Soap, but since I haven't had any in years I now use Murphy's oil soap. BTW
you can wash your celery in it and it is Kosher Parve (no meat, no dairy,
another story).
The only advantage I can see with Vaseline is that it might fill up small
indentations in your first mold that would cause undercuts. But I would rather
see you fill these with modeling clay.
Vaseline or vegetable clogs the pores of your mold and will slowdown the
absoption of water.
Any good general ceramics text book will give detailed directions but here they
are.
1. Water down paste Murphy's 1 to 1 with water. If you have pourable Murphy's
don't dilute it.
2. Don't contaminate your main jar of murphy's work from a small container.
3. using a soft brush applie murphies to the surface you want to release.
4. Rinse with a natural sponge gently, using clean water
5. Reapply the Murphy'slathering it into the mold.
6 Rinse again. By now you should see the water berading on the surface of the
mold.
7. Reapply the Murphy's lathering again and rinse again.
The Akali Oleates and Stearates in in the soap combine with the calcium in the
mold and form soap scum. The scumm is the separator.
Louis
Joy Holdread wrote:
> ----------------------------Original message----------------------------
> > One thing that differs in the way I teach the process is to use Crisco
> > instead of petroleum jelly. It's easier to work with, better for your skin
> > since it's vegetable based, and easier to clean up. Models usually comment
> > on how soft their skin feels.
> >
> Has anyone made a plaster mold using a plaster mold? I want a negative of a
> press mold. Rather than buy mold release has anyone used petroleum jelly or
> Crisco on a plaster mold to make a reverse?
> Joy in Tucson just aching for a week of studio time.
--
Louis Katz
lkatz@falcon.tamucc.edu
NCECA Director At Large
Texas A&M-CC Division of Visual and Performing Arts Webmaster (512) 994-5987
Visit the NCECA World Ceramics Image Database
the Gallaghers on tue 9 mar 99
>the discussion about plaster the recommendation was to not use petroleum
>products with plaster, it plugs the pores . What works in this case?
>Bryan
I have used Vasoline off and on for various plaster casting projects. The
main reason I would choose not to use it is when the final piece cast from
the mold is to be made of a neoprene, or other liquid laytex or rubber
product. The petrolium will inhibit the proper curing of these materials.
For clay use I can't really see a great problem, the vasoline is absorbed
into the plaster enough so that the parts of a mold do not set to each other
when making a multiple part mold, but the mold afterwards does not seem to
affect clay. When casting directly from a clay original, if there are no
undercuts to hold the piece in, the original should slip out easily without
any mold release; such as with a tile. Plaster does not set to clay. This
should be obvious when you use plaster bats for drying wet clay.
I have also used a tincture of green soap for a mold release, available at
any store or phamacy that sells facial soaps. This is a liquid that is
brushed on in mulitple layers allowing to dry completely between
applications. The build up creates a skin of soap that is waxy in
appearance and washes off when pulled from the mold.
If you have any outher questions you can contact me directly.
Michelle
In Oregon
Puppets@msn.con
eden@sover.net on thu 18 mar 99
A nearby elder potter advised me once to soak a mold in a mold-soap
solution. He always insisted that the soap that is working for you is the
soap that has soaked into the plaster, not the stuff that is on the
surface. If you go to the trouble of soaking a mold, do add a squirt of
your mold soap to the water.
Eleanora
At 11:49 PM 3/7/99 -0500, you wrote:
>----------------------------Original message----------------------------
>If you wish to make a mold from a dry plaster original, a good tip is to
>FIRST SOAK THE PLASTER ORIGINAL IN WATER UNTIL IT IS COMPLETELY
>SATURATED. Take it out and dry off the surface well. Then apply your
>coats of mold soap or Murpheys oil soap mixed half and half with water,
>wiping off between coats, until water beads up on the surface of the
>original.
>
>If you are making a mold from freshly cast plaster, it will already be
>saturated, so you can go ahead and soap the mold.
>
>
>___________________________________________________________________
>You don't need to buy Internet access to use free Internet e-mail.
>Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
>or call Juno at (800) 654-JUNO [654-5866]
>
Eleanora Eden 802 869-2003
Paradise Hill
Bellows Falls, VT 05101 eden@sover.net
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