Silicone Mold problem

Jewelry Discussion
1

In spite of using Modeler’s Silicone mold release on my molds, the
waxes are coming out half stuck to the sides. Does anyone have a
suggestion to fix my problem?

Thanks in advance!
Karen Strauss in snowy New York

2 
In spite of using Modeler's Silicone mold release on my molds, the
waxes are coming out half stuck to the sides. Does anyone have a
suggestion to fix my problem?

Hi Karen, From your statement that your waxes are stuck to your mold,
and silicone release spray is not releasing the wax, I can determine
that you are injecting into a natural rubber mold material like
castaldo gold or Kerr rubber( and others). The mold you are using is
yellowish in color or white. What causes the wax to really stick to
these types of rubber is when your wax is way to hot…You may have a
faulty thermometer if you are using one… if you are not using one,
then you should get a stainless steel dial type thermometer that
will fit into the thermowell (hole) on top of the wax pot lid. This
will give you a closer reading of the actual temperature of the wax.
If the waxpot is less than 1/2 full, you may not be getting a proper
reading if you already have a thermometer.

If you are relying on the temperature reading of the knob on the
side of the waxpot… good luck !!! These are known to be completely
off and should not be used to gauge your wax temp unless it is
calibratable (very few are) and has been calibrated.

I would suggest you bring your wax temp down to about 150- 155 oF
and wait a good 1/2 hour before shooting waxes… your problem
should go away.

If you should need castings or any other help, Please contact us off
list at sales@racecarjewelry.com We do casting, finishing,
moldmaking, model making , soldering, assembly, and a variety of
other things for designers, stores and people in the trade. Best
wishes, Daniel Grandi

3 
    In spite of using Modeler's Silicone mold release on my molds,
the waxes are coming out half stuck to the sides. Does anyone have
a suggestion to fix my problem?

Hi Karen, Give your molds a light dusting with parting powder. I like
to use corn starch. Be sure to dust all of your cuts as this also
helps the air to escape from the mold giving you a more complete
fill.

Timothy A. Hansen
TAH Handcrafted Jewelry
web-site: http://www.tah-handcrafted-jewelry.com
e-mail: tim@tah-handcrafted-jewelry.com

4

A fellow jeweler recently suggested using talc powder, such is found
in some baby powder. Make sure you don’t get cornstarch instead.
Basically, what we did is take an old t-shirt, put a small pile of
talc powder on it (about the size of a golf ball), then wrap the
t-shirt around the powder and secure it with a rubber band or string,
forming a ball-like lump in the t-shirt. Before we inject wax, we tap
the ball on each side of the mold. The talc penetrates the t-shirt
and lightly dusts the mold. Hope that helps!

JoAnna Kelleher
Pearl Exotics Trading Company
Phoenix, AZ

5

Karen, What was your master made of? If you are using a natural
rubber such as Castaldo gold bronze, brass or copper models will
leave a brown oxide film that is baked into the rubber and coats the
mold surface. Always Siver plate a copper based master.

Also, too high a wax temp. or too warm a mold would cause these
problems. There might also be an incompatability between silicone and
natural rubber.

Good luck, Andy Cooperman