Wax Injection unfilling

Jewelry Discussion
1

Dear Friends…

I am facing problem of unfilling at the time of Wax injection in
rubber mold Prongs are not comming as it has to be. When I am using
talcum powder, I am getting the better filling. Can any one tell me
what are the effects of powder on injection ? Is it wise to use
powder ? Is there any alternative to get better filling ?

With Best Regards,

Ketan J Shah.
P.D. Executive.
K.B.S. Designs.

2

Talc powder works to keep the air cut vents open enough to let the
air out ahead of the incoming wax. This is only one possible factor
for the wax not filling-Small adjustments in wax type or temperature
or pressure can help. Or you may be gripping the mold too tightly for
this particular item.

Daniel Ballard

3

Do you have air vents going to the out side edge of the mold?? If
not at the end of each prong make a thin cut not too deep towards the
top of the mold, In lieu of that being feasible, just a very small
drill like a 65 or so and at the end of the prong drill through the
mold, what’s happening is that air get trapped in the ends of the
mold and won’t let the wax in, Talc is OK just use it very sparingly.
Especially if this is a silicone mold, I borrowed a make up brush
powder will slowly degrade the mold quality if used in large amounts
but if used sparingly it’s OK just don’t try and use a silicone spray
in the same mold. The other choice is a combo vacuum / injector Nice
but about 2500.00 last I checked. You will find that by cutting air
release vents in molds that they will pull easier, you can also drop
the wax temp a few degrees (less shrinkage) and also lower your
injection pressure, Less parting lines and flash to clean off the
model

Good luck
Kenneth Ferrell

4 
    I am facing problem of unfilling at the time of Wax injection
in rubber mold Prongs are not comming as it has to be. When I am
using talcum powder, I am getting the better filling. Can any one
tell me what are the effects of powder on injection ? Is it wise to
use powder ? Is there any alternative to get better filling ?

Incomplete fill out in a rubber mold is because of air that can’t
get out of the mold, pockets of air in prong tips, and so on. Talc
creates a small gap between the two halves of the rubber mold so that
air can leave the mold. Proper mold cutting along with a fine dusting
in the cuts helps avoid trapped air pockets. A vacuum injector also
works nicely in most cases.

Jeffrey Everett