I’m thinking of creating molds out of polymer clay which could be
used to “cast” Art Silver Clay. What would I use for a parting
powder ? What effect would the standard sand casting parting powder
have on the silver clay ? Any suggestions for a better substance to
use ?
Brian Corll
Vassar Jewelers
1002 East Simpson Street
Mechanicsburg, PA 17055
I’m not clear on what your mold will look like, but what about
coating in olive oil? Wouldn’t that act like a spray mold release?
:-\ Also, would you be pressing the clay into the mold and peeling
the piece out?
Veronica
If you haven’t worked with precious metal clay do a lot of reading
first. The stuff is a hassle all the way around.
I’ll take silver grain and casting equipment over metal clay any
time. Metal clay is a P.I.T.A.
It’s a pain to get out of polymer clay molds, because it stretches
when pulled out. You can’t fire it IN the polymer mold because the
clay has to fire at a much hotter temp than the polymer can handle.
You can’t use parting powder with metal clay because it might become
mixed in and change the way it dries or fires. And deities help you
if your kiln isn’t calibrated properly–several hours of work can go
“poof” and turn into .999 silver blobs in a heartbeat. (been there,
done that) The substances of choice for making metal clay molds are
any of the two part silicone mold products.
They have enough “give” to release the still-soft metal clay without
distorting it too badly, and they naturally release mineral oil which
acts as a mold release. I found a good forum that deals specifically
with metal clay issues at the Art Jewelry magazine website.
I know there are several other forums out there on metal clay
specific websites, but the Art Jewelry site seems geared more toward
beginners than the other ones.
Kathy Johnson
Feathered Gems Jewelry
http://www.fgemz.com
I'm thinking of creating molds out of polymer clay which could be used to "cast" Art Silver Clay. What would I use for a parting powder ?
You don’t need anything-- the silver clay will not stick to the
(baked) polymer clay. But if you are worried, use olive oil-- you
know that’s OK with the clay.
Noel
Hi Brian,
When I created and used my own polymer clay molds, I used cornstarch
as a release. Not only is it safe, it’s also biodegradable.
The only thing about using a hard mold with a soft substance is when
you pull it out, you distort the raw clay.
You might want to check out a modeling compound made specifically
for polymer. Ones i know of are Miracle Mold (created & marketed by
one of the members of polymerclaycentral.com) and there’s protoplast
molding compound (found at polymerclayexpress).
The express site also has some nice textures & molds (I’m a former
happy customer).
Protoplast Thermoplastic Molding Products
Hope that helps some,
Tracy
Tracy’s Treasures
Brian, I use olive oil or some other non petroleum based oil to
lightly coat my polymer molds with before I use them with the metal
clay.
Hello Brian,
Once the polymer clay mold has been baked, the release for metal
clay pressed into it is the same as for working with metal clay with
other objects (rollers, tissue blades, one’s hands). The molds, as
with other objects, must be lightly oiled, using liquid oils like
olive oil (which I still prefer) or badger balm.
Check out the PMC Guild website (pmcguild.com) and go to the
Discussion Board to check out ‘conversations’ about the use of metal
clay. It’s quite informative. If you are a member of the Guild you
can also access the archives of these discussions and other
not otherwise available to non-members. Guild membership
also gives you a discount on Precious Metal Clay materials and tools
at Rio.
For an intense burst of come to the PMC Conference next
week at Purdue University in Indiana (links on the Guild website).
This conference has always been an excellent source of
All metal clay-ers (PMC and ASC) attend.
Hope this helps,
Linda Kaye-Moses
Thanks, Kathy. What I was thinking of doing was creating the polymer
mold, baking it, then pressing the silver clay into the mold. I would
cut a couple of small pieces of silver wire and stick them into the
back of the silver clay, then let the silver clay air dry over night.
Grab the silver clay by the silver pins sticking out of it and it
should lift out of the mold nicely. This is my theory anyway. Next
I’ll really try it…
Brian Corll
Brian Corll, Inc.
1002 East Simpson Street
Mechanicsburg, PA 17055
Tel.: (717) 691-0286
Hello Brian
Iv’e done some of the “casting” in polymer clay with art clay (low
fire 650) Instead of powder I used a tiny bit of olive oil. This
works great.
Michael Knight was offering a free sample to try out “Rapido” here
on this forum last march. I replayed and explained what I wanted to
use it for. Michael pointed out the Castaldo’s: “Quick Sil” he
thought would sooth my purpose better. And right here I will thank
him for this advice. Thank you Michael!! (Quick Sil is a two
component sort of rubber or silicone. You just mix a and b in equal
amounts and it hardens of on its own in 15 min, no oven needed)
Most of the time I make my molds out of the “Quick Sil” now. Nice
about it is that the mold stays flexible and the clay comes out
perfect for you can gently deform the mold (slight undercuts are no
problem). Polymer goes hard and can give problems on that point. The
Quick Sil mold I find is also less fragile.
I don’t work for Castaldo I’m just very happy with this product :))
You can choose on both types molds, quick sil ot the polymer,
weather you take out the (art) clay wet or after the has dried. When
wet you got a fair chance of damaging or deforming your clay. When
dry it is sometimes tricky to take them out, especially with the
polymer clay mold for she doens’t “give”. The nice thing however
about the clay is: even when it breaks coming out of the mold (when
dry) you can “glue” it back together with a bit of water
Good luck
Nicky
Hello,
Just thought this might help clarify a few points Re: using molds
and Metal Clay.
The process of using Metal Clay with Molds is not ‘casting’, but
is press-molding. The clay is pressed into a Mold. When using the
Mold, the Metal Clay is taking an impression of the Mold image.
A polymer clay mold can be made in a number of ways:
-a Modelcan be pressed into the polymer clay;
-the polymer clay can be carved;
-the polymer clay can be hand-formed;
-etc.
Before a Model has been pressed into polymer clay, a release
agent must be lightly dusted on the polymer clay.(A good choice is
50:50 talcum powder/corn starch, though each can be used alone.) This
permits the model to be removed without it adhering to the polymer
clay or distorting the Mold image. This is the release agent for
polymer clay only; not for METAL CLAY.
Once the polymer clay is baked it is no longer a soft or malleable
material; it becomes hardened. When using the BAKED polymer clay Mold
with METAL CLAY, the Mold is lightly coated with an oil as a release
agent (olive oil and/or Badger Balm or something similar). This oil
is the release agent for METAL CLAY only; not for polymer clay.
Other moldmaking materials: thermoplastic
(protoplast/aquaplast/etc.); two-part silicone materials; plaster of
paris, papier mache, etc.
These processes may seem confusing or complicated but are really
quite easy to use. Sometimes it’s helpful to take a class/workshop
just to give you a jumpstart on a process. There are many classes
available all across the U.S. and in other countries around the
world. Check out the PMC Guild website or other metal clay websites
for classes in your area (both Certification and General).
Hope this is helpful,
Linda Kaye-Moses
If you haven't worked with precious metal clay do a lot of reading first. The stuff is a hassle all the way around. I'll take silver grain and casting equipment over metal clay any time. Metal clay is a P.I.T.A.
Metal clay is only a pain if you don’t know how to use it, like
anything else. I’d rather work in Art Clay Silver than go through
all the hassle of lost wax, casting and polishing. Plus, I do thinks
with metal clay that would be way more of a PITA. It’s all a matter
of perspective, isn’t it?
Jackie