Rhonda Simmons on tue 4 aug 98
well after eight weeks of working on a sculpture piece,i decided to try and
make
a plaster mold....its been ten years since i've done anything with casting
and plaster due to contrary belief by no means did all of past experiences
come
rushing back to me,so my partner is quickly mixing the plaster of paris as per
box instructions and i'm putting on a slip of dish detergent please the
more experienced hold your laughter,the slip was on the sculptural piece
so that the
plaster would come away from the clay moving right along the plaster dried
and we used a chisel and hammer to break the clay piece free well i lost
some of my sculptural which i will repair tomorrow i'm disappointed but i
know there is a lesson to be learned here for me,i'm determined to learn
this casting technique
even if it kills me.......i'm asking for some input and working knowledge
on plaster casting and please i like to keep it simple the whole
process.....thanks
for your knowledge in this matter .....BLESSED BE............Rhonda ..Maple
Ridge,British Columbia
Marcia Selsor on wed 5 aug 98
Dear Rhonda,
After some 35 years of plaster experience, I can only say don't use plaster of
Paris for art projects. Use a better grade such a casting plaster, pottery
plaster. hydrocal. These increase in hardness as listed.
Next, cast wet or leather hard clay. Your idea about the detergent was ok.
Petroleum jelly or vaseline is better. Check very carefully for any undercut
and adjust your pieces accordingly. You may end up with a three , four, eight
piece mold. Be sure to "key" each section to guarentee alignment when you
reassemble it.
When you mix the plaster, add slowly plaster to water until there is an island
that doesn't sink. Then mix smoothly without stirring in air bubbles. Tapping
on the table before you cast, will bring air bubbles to the surface. Swoosh
them out of the plaster before you cast.When you can draw your finger across
the surface and see a ripple staying on top, POUR! There isn't much time after t
Marcia in Montana
Rhonda Simmons wrote:
>
> ----------------------------Original message----------------------------
> well after eight weeks of working on a sculpture piece,i decided to try and
> make
> a plaster mold....its been ten years since i've done anything with casting
> and plaster due to contrary belief by no means did all of past experiences
> come
> rushing back to me,so my partner is quickly mixing the plaster of paris as per
> box instructions and i'm putting on a slip of dish detergent please the
> more experienced hold your laughter,the slip was on the sculptural piece
> so that the
> plaster would come away from the clay moving right along the plaster dried
> and we used a chisel and hammer to break the clay piece free well i lost
> some of my sculptural which i will repair tomorrow i'm disappointed but i
> know there is a lesson to be learned here for me,i'm determined to learn
> this casting technique
> even if it kills me.......i'm asking for some input and working knowledge
> on plaster casting and please i like to keep it simple the whole
> process.....thanks
> for your knowledge in this matter .....BLESSED BE............Rhonda ..Maple
> Ridge,British Columbia
the Gallagher's on wed 5 aug 98
>i'm asking for some input and working knowledge
on plaster casting and please i like to keep it simple the whole
process.....thanks
for your knowledge in this matter .....BLESSED BE............Rhonda ..Maple
Ridge,British Columbia
Rhonda,
I have never heard of using dish soap as a mold release. Tincture of green
soap is what I have used, or vaseline, or Pam. Water base clay will pull away
from plaster while wet, or still in the leather stage if you use any of these
as a mold release. The green soap needs to be applied in three thin layers,
allowing to dry between each. Be sure to hit all areas well.
Don't let the clay dry in the mold, it will be very difficult to remove, any
clay residue can be washed out with water. I'm assuming you were casting a
piece that was leather hard, not bone dry.
But, let's back up a minute and discuss the piece to be cast. Does it need a
one, two or multiple part mold? Are there any undercuts where the clay will
hang up as you pull the mold from the piece?
There are many good mold-making/plaster casting books in libraries and book
stores. I suggest you pick one up.
Michelle In Oregon
Mike Gordon on wed 5 aug 98
Hi,
I would like to know if the sculpture was bone dry at the time or
leather hard? Pay close attention to the undercut areas, too. Mike
Sheilah Bliss on wed 5 aug 98
Hello Rhonda -
Congratulations on at least trying to make a mold. I've thought of doing it
for a while, just haven't yet done it... (I know I left my nerves SOMEWHERE
around here...) but I have a massed a few books on the subject. I'm pretty
sure someone else or several someone elses on ClayArt will offer first hand
advice, but thought you might like the titles of a couple books -- one is The
Potter's Manual by Kenneth Clark... it's published by Chartwell Books, another
is The Big Book of Ceramic by Joaquim Chavarria published by Watson Guptill.
These both have pictorial instructions, and mention several methods of making
molds.
Good Luck.
Sheilah Bliss
Mark Heimann on thu 6 aug 98
Hi
I've been using Murpy's Oil Soap, slighty diluted with water, in a spritz
bottle for carved drape and slump mold release. It works swell. Smells
okay, too!
Mark Heimann , sunny (still!) Oregon
----------
> From: the Gallagher's
> To: CLAYART@LSV.UKY.EDU
> Subject: Re: First casting experience
> Date: Wednesday, August 05, 1998 9:35 AM
>
> ----------------------------Original message----------------------------
>
>
>
> >i'm asking for some input and working knowledge
> on plaster casting and please i like to keep it simple the whole
> process.....thanks
> for your knowledge in this matter .....BLESSED BE............Rhonda
..Maple
> Ridge,British Columbia
>
>
>
> Rhonda,
> I have never heard of using dish soap as a mold release. Tincture of
green
> soap is what I have used, or vaseline, or Pam. Water base clay will pull
away
> from plaster while wet, or still in the leather stage if you use any of
these
> as a mold release. The green soap needs to be applied in three thin
layers,
> allowing to dry between each. Be sure to hit all areas well.
> Don't let the clay dry in the mold, it will be very difficult to remove,
any
> clay residue can be washed out with water. I'm assuming you were casting
a
> piece that was leather hard, not bone dry.
>
> But, let's back up a minute and discuss the piece to be cast. Does it
need a
> one, two or multiple part mold? Are there any undercuts where the clay
will
> hang up as you pull the mold from the piece?
>
> There are many good mold-making/plaster casting books in libraries and
book
> stores. I suggest you pick one up.
>
> Michelle In Oregon
Joy Hought on thu 6 aug 98
for Marcia in Montana
when you pour multipiece molds, what do you use to separate the sections
when you're pouring? I've seen brass wedges used, or soft clay. it seems
to me the wedges would be more precise, but i'm not sure where to get them.
Any suggestions?
Joy in Irvine
Sheryl A. VanVleck-Wells on fri 7 aug 98
When I make a multi-part mold, I just use clay as my walls. It's not real
neat but gets the job done. For the second part, I coat the plaster that is
already done with a mold release, build a wall, or use wood for the retaining
wall and pour. As long as the existing plaster has a good coating of
something like Murphy's oil soap on it, it should separate without a problem.
Sheryl A. VanVleck
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