Casting a polymer clay item

Hello all,

I have a friend who does a lot of work in polymer clay. He works it
just like wax, hardens it in the oven, engraves it, adds more clay,
etc. and produces some of the most amazing sculptural beads, tiles,
and jewelry. He had a jeweler make some molds of some of the pieces
he did and cast them up in silver, and while they are pretty good, he
isn’t satisfied with the level of detail he is getting. He was told
that you can’t make a vulcanized mold of a polymer clay piece because
it will melt, and the material that the jeweler used to make the mold
leaves a little to be desired. Can anyone recommend a good caster
that can deal with making a mold from a polymer clay piece, and then
do small production runs in sterling silver?

Thanks!
Eric

Can anyone recommend a good caster that can deal with making a mold
from a polymer clay piece, and then do small production runs in
sterling silver? 

Eric,

You could try casting a metal master directly from the polymer
piece, or better yet, get your friend to switch to sculpting wax. Not
sure how clean the polymer would burn away prior to casting, but I’ve
had success with a number of plastics. Then make the mold off of the
new metal master.

Mary Latterman
Latterman Handmade
http://www.latterman.com/custom/customers/index.html

Have him try Quick-Sil by Castaldo. It’s a two-part silicone mold
material that takes great detail from models. Great stuff, and
doesn’t need to be vulcanized, so it won’t hurt the polymer clay
original. http://www.castaldo.com

–Kathy Johnson
Feathered Gems Pet Motif Jewelry
http://www.featheredgems.com

Eric,

Some room temperature vulcanizing rubbers are sensitive to
contamination (sulphur is one offender as I recall) Usual result is
a gooey mess as the rubber doesn’t cure. In your friends case perhaps
the mold is good but the detailing which suffices for polymer clay is
insufficient for silver. My suggestion would be to inject a modelling
wax into the RTV mold and re-detail the wax, and further refine and
finish the resulting silver casting. Then make a production mold from
this model. The model has to as close to the desired result as
possible.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.aztec-net.com/~jdemand