Paul Ringo on thu 6 dec 01
Depending on the detail and purpose of the model/mold I have also used
green soap, inexpensive liquid dish soap, vaseline, and spray release
agents with success
I just participated in a mold making workshop last weekend (my first =
real pottery workshop btw). We made some molds for bonsai pots with the =
skilled hand of Bill Newman of Southern Pottery leading us. He said the =
mold soap had lye in it and I assumed (maybe falsely) that it was the =
caustic lye that had something to do with the function of mold soap. =
Did I assume wrong? (which is quite possible). How is it that these =
other agents could get the job done just as well without problems? I =
never had an inkling that there was so much chemistry involved in =
pottery until I got started a few short months ago.
Paul Ringo, Lake Charles, La.=20
Snail Scott on fri 7 dec 01
At 07:02 PM 12/6/01 -0600, you wrote:
>Depending on the detail and purpose of the model/mold I have also used
>green soap, inexpensive liquid dish soap, vaseline, and spray release
>agents with success.
Lots of things work well as release agents. If
the mold is intended for slip-casting, though,
it will work better if you avoid the greasy
stuff, like vaseline or cooking spray. They
seem to interfere with good absorption.
-Snail
Ceramic Design Group on fri 7 dec 01
on 12/7/01 10:17 AM, Snail Scott at snail@MINDSPRING.COM wrote:
> At 07:02 PM 12/6/01 -0600, you wrote:
>> Depending on the detail and purpose of the model/mold I have also used
>> green soap, inexpensive liquid dish soap, vaseline, and spray release
>> agents with success.
Avoid using vaseline as as a mold soap it will leave marks the plaster parts
cast from the model or other parts.
I would concur with Bill Campbell that the best parting compound is
Polyurethane Parting Compound available from Permafelx in Columbus Ohio. We
have used this material for well over 20 years or so! As wel as a host of
other Permaflex products.
It may be useful to understand that there is a broad range of these products
and what parting compounds do is prevent the absorption of material into the
surface by acting as a parting agent. These are not sealers in the true
sense. Permaflex makes mold dressings and sealers as well as PUP. We have
also used several aerosols and have found them quite inferior. Murphys Soap
is ok as is Fels Naptha if you don't have PUP, but I would definitely use
PUP in any instance.....plaster from plaster, rubber from plaster, from
wood, etc. etc.
Jonathan
Snail Scott on sat 8 dec 01
At 12:20 PM 12/7/01 -0700, Jonathan wrote:
>
>...the best parting compound is
>Polyurethane Parting Compound available from Permafelx... Murphys Soap
>is ok as is Fels Naptha...
Permaflex is a great source for professional mold
materials of all sorts. Another is the Smooth-On
company, which also makes a nice polyurethane
parting compound. Murphy's Oil Soap is probably my
favorite among the 'supermarket'-type materials.
>Avoid using vaseline as as a mold soap it will leave marks the plaster parts
>cast from the model or other parts.
If you must use vaseline, wipe it back throughly
with a lint-free rag, to eliminate the marks that
Jonathan mentions. If it doesn't wipe well, heat
it slightly to make it less viscous and try again.
Only the slightest residue is needed to act as a
parting agent, so don't worry about removing too
much.
-Snail
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