David & Diane Chen on wed 28 jul 99
------------------
Well having spent a fair amount of time in archives and books the past few =
days,
I am a little confused about mold soap vs releasing agents. My books =
indicate
that mold soap is used in the preparation of the mold only. For a releasing
agent the book suggests talc, yet in the archives, I was reading quite a bit
about burnishing mold soap onto the plaster. For my mold this is impossible=
due
to the fine detail. Any suggestions?
Diane
Massachusetts
Dwiggins, Sandra (NCI) on fri 30 jul 99
Here is my understanding of the differences (with due respect to Ron Roy, I
preface this with my possible ignorance of all the issues involved)
There are different processes involved in working with plaster molds.
One is actually making the mold.
One is pouring slip, or pressing clay into the already made mold and taking out
a clean clay form.
Mold soap is used when you are making the mold. To keep the different pieces of
the mold from sticking to each other when pouring the plaster, you apply mold
soap to the plaster piece of the mold that has been poured and is already set.
On the side of the set-up plaster piece that will be in contact with the plaster
piece you are about to pour, you apply the soap, burnish with a rag, apply again
and burnish. I was taught that you do this three times. Then pour the next
section of the mold. When this sets up, just repeat the process until you've
poured all the plaster for the mold. The face of each section that touches the
face of another section will have mold soap on it. When you finish and remove
the surrounding material from your mold, all the pieces should easily come apart
and will fit back together.
Releasing agents are compounds put into a mold to help release the clay or slip
more easily, without sticking or distortion. These can be cornstarch,
talc--powdery stuff that absorbs some of the water so it keeps the surface of
the clay dryer and easier to release from the mold. I'm sure there are others
used in industry, and by other potters that I don't know about.
I have used Murphy's Oil Soap as a releasing agent when I want to make a plate
or bowl from a non-plaster mold, i.e. glass or other ceramic and a mold soap to
make a plaster mold of a glass or ceramic item.
Now that's how I understand it. If I'm wrong or misstated anything, I'm
glad---because somebody will tell me where I'm wrong and then I will have
LEARNED something.
Sandy
Sandra Dwiggins
Sandra Dwiggins
Technical Information Specialist
Office of Cancer Information, Communication and Education
National Cancer Institute
National Institutes of Health
e-mail: sdwiggin@exchange.nih.gov
fax:301-480-8105
phone: 301-496-7406
-----Original Message-----
From: David & Diane Chen [SMTP:parishrd@netway.com]
Sent: Wednesday, July 28, 1999 2:17 PM
To: CLAYART@LSV.UKY.EDU
Subject: molds, soaps, and releasing agents
----------------------------Original message----------------------------
------------------
Well having spent a fair amount of time in archives and books the past few days,
I am a little confused about mold soap vs releasing agents. My books indicate
that mold soap is used in the preparation of the mold only. For a releasing
agent the book suggests talc, yet in the archives, I was reading quite a bit
about burnishing mold soap onto the plaster. For my mold this is impossible due
to the fine detail. Any suggestions?
Diane
Massachusetts
Libby Douglas on fri 30 jul 99
Diane,
I've had good luck pulling a variety of casting materials from extremely
detailed plaster molds by using a wax-based release agent. My favorite is
531, made by Synair Corporation in Chattanooga. You can order directly from
them on their 800 number - 800-251-7642. I'm thinking it's less than $5 a
can, and it goes pretty far. Use two coats and let it dry thoroughly.
Good luck!
At 02:16 PM 7/28/99 EDT, you wrote:
>----------------------------Original message----------------------------
>------------------
>Well having spent a fair amount of time in archives and books the past few
days,
>I am a little confused about mold soap vs releasing agents. My books indicate
>that mold soap is used in the preparation of the mold only. For a releasing
>agent the book suggests talc, yet in the archives, I was reading quite a bit
>about burnishing mold soap onto the plaster. For my mold this is
impossible due
>to the fine detail. Any suggestions?
>
>Diane
>Massachusetts
>
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"In a way, art is a theory about the way the world works to human beings.
...what artists have accomplished is realizing that there's only a small
amount of stuff that's important, and then seeing what that is."
---------------------------------------------------------------------------
James Gleick
Peace and Love
Libby
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Timothy Dean Malm on fri 30 jul 99
Greetings: So as to avoid loosing detail from your molds, try dusting the
surface of the mold with corn starch as a releasing agent. This works well
for pressmolding. Sincerely, Tim Malm
Andre van de putte on fri 30 jul 99
-------------------
Green Soap Tincture sold at many pharmacies works real well....
Andr=E9
N=E9e Massachusetts
Now Chicago
Ross Hartman on sun 1 aug 99
Diane;
I have been a mold maker for more than thirty years, I'll try to add to
your confusion
FWIW:
mold soap (I'm referring here to the green stuff that comes in 50 gal
pails and you mix with water to thin to use consistency) can be used in
mold making as:
1) Sizing (where I define sizing as a way to make plaster non-absorbent
to cast plaster against) some people have used things like shellac as a
sizing, it just happens that mold soap makes the best one. This is the
case where 'burnishing' is used, although I use a different term.
2) Parting Compound (where I define a parting compound as a specific
type of releasing agent, that being 'parting' one mold from another,
mostly a production mold from a master (or case mold)).
There are other things that work as sizing, and there are other things
that work as parting compounds, but there is none to my knowledge that
will work for both, as well as mold soap.
The cornstarch is another specific type of releasing agent, but it has
nothing to do with mold making. It appears that it is used mostly for
press molds to release the clay that you have 'pressed' into a mold. It
may be used in slip casting (I'm not sure) but if you need to use it in
slip casting you have some sort of problem related to a mold that is
shot (i.e. used up, by casting a hundred or maybe two hundred times) or
a slip that is out of whack (i.e. viscosity, water content, etc are off,
probably way off)
Hope this helps...
L8R/Ross
Jeff Ferris on wed 4 aug 99
For a release agent I have used
- a very light spray of WD-40.
- Talc. But talc is a flux. On the other hand, it gives a nice sheen
to my tiles that I finish with just iron oxide stain.
- Baby powder. Which nowadays is mainly cornstarch, but it smells the
best.
-- Jeff Ferris
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"You're gonna have to kill me to make me stop." -- Cool Hand Luke
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