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I will have the opportunity on my new job to (perhaps more than occasionally) crank out a mould or two.
What moulds are out there in cannon ball sizes? How much shrinkage does one get with zinc or aluminum?
I had some made by a local pattern maker - he made a match plate and did sand casting - $16 each but there was irregular shrinkage. Surface finish was OK. There were a few voids one could see on the surface.
I've heard that some people will suspend a sand core inside to make the walls thinner and hence less problems with irregular shrinkage.
What are your experiences?
What moulds are out there in cannon ball sizes? How much shrinkage does one get with zinc or aluminum?
I had some made by a local pattern maker - he made a match plate and did sand casting - $16 each but there was irregular shrinkage. Surface finish was OK. There were a few voids one could see on the surface.
I've heard that some people will suspend a sand core inside to make the walls thinner and hence less problems with irregular shrinkage.
What are your experiences?