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Warning: Skipping mold pre-heat gave me fewer defects
Everyone in the shop says to always pre-heat your molds to avoid cracks. I tried skipping it on small brass jobs to save time. The casts came out smoother and with less shrinkage. Now I only pre-heat for large iron pours.
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william661mo ago
Honestly, I do the exact same thing now for small zinc alloy casts. Found that a cold silicone mold gives sharper edges on thin sections, like under 1/4 inch. Only time I pre-heat those is if the part has super thick areas, then it helps even things out.
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felixlewis1mo ago
What kind of molds are you using? I had the same thing happen with small aluminum parts in green sand molds. The cold mold seemed to help it set up faster and hold detail better. I still heat for bigger stuff, but for little things, skipping the preheat just works.
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