I just made my first mold using a Smooth-on Co. silicone mold material. The mold looks fine but the finished pewter castings come out covered with heavy pitting. I coated the mold cavity with talm powder or graphic powder but I still get this pitting effect on the finished piece. Can anyone tell me what I'm doing wrong or what I'm failing to do? Thanks.
I recall having some minor problems like this using Dow Corning Silastic
3120 for pewter cast>I just made my first mold using a Smooth-on Co. silicone mold material. The
Looks like tiny gas bubbles ?
You've either got a new mould and this will disappear after a few casts, or else you're pouring too hot for the mould material. I don't know what your "pewter" alloy is, but some of the modern lead-free alloys are too hot for some silicones.
If the mould surface starts to break up, you're too hot.
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