There are MANY high temp “silicon” direct pour molding rubbers
available, not just Corning (I assume you are using a high temp
silicon in this reference). Metal freezing might be corrected by
a different spruing design. Also what alloy of pewter are you
using? How is your temperature regulation or the molten metal?
Are you gravity pouring or centrifical? Have you considered
having the castings done by a house specalizing in pewter
castings? They have already worked out the bugs you are dealing
I like to do as much of my own work as possible so I understand
if you are not willing to go to an outside caster. But temp
control and alloy would be 2 areas I would be concerned with. I
would question the use of a brone mold, especially in
combination with plaster exterior, why go to these lengths?
Talk with a pewter casting house and see what they might
recommend. Not knowing the size of the piece you are working
with makes some discussion areas difficult, but spin casting is
used extensively for pewter but so is gravity casting other
factors are in place.
Where are you?
John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/ Bloomin’ Wax Works. etc.
PO Bx 44, Philo
Ph 707-895-2635 FAX 707-895-9332
If your’re headed in the right direction,
each step, no matter how small, is getting you closer to your goal.