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Question for casters...Shrinking????


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#1 KT EASTMAN

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Posted 13 May 2007 - 07:08 AM

I seem to remember a time that Resin Casters had to make the molds slightly bigger to make up for shrinkage during curing. Is this really what has to happen if I wanted to say...cast a grille?? Just curious because I do not hear about people oversizing their molds to allow for shrinkage. Any info. would be great!!!! KT

#2 BigPoppa

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Posted 13 May 2007 - 11:36 AM

I seem to remember a time that Resin Casters had to make the molds slightly bigger to make up for shrinkage during curing. Is this really what has to happen if I wanted to say...cast a grille?? Just curious because I do not hear about people oversizing their molds to allow for shrinkage. Any info. would be great!!!! KT


I'm not sure how you would make a mold bigger, you would have to somehow enlarge the master. But the faster the resin cures, the more it shrinks.

#3 Modelmartin

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Posted 13 May 2007 - 04:30 PM

Modern Urethane resins have almost zero shrinkage. I have measured castings against masters and had to use a caliper to find even a few thousandths shrinkage. I can't vouch for some of the cheezy resins out there, though.