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Unpopular opinion: I used to think you could get away with a single coat of zircon wash on our greensand molds.
Tried it on a batch of 50 gray iron castings last month and the burn-in was so bad we had to scrap half of them. Anyone have a good ratio for a thicker slurry that still drains properly?
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kimr916d ago
That single coat theory is a fast track to the scrap bin. We run a 3 to 1 zircon to alcohol mix with a dash of binder for our heavier sections. Lets it build up without turning into a sticky mess that ruins the drain.
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mason.drew6d ago
Interesting point @kimr91. That 3 to 1 ratio seems pretty thick. How heavy are the sections you're coating, and what's your drain time like? I've seen mixes that dense lead to a crazy amount of slurry waste because it doesn't drain cleanly, it just builds up in the lines. Are you running a special pump setup to keep it moving without settling?
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emma_jones6d ago
That "single coat theory" being a fast track to the scrap bin is dead on. It reminds me of how people try to cut corners with sealant or paint, thinking one thin layer will hold. The material just can't handle the stress and it fails every time. You see it everywhere when folks skip the proper prep work to save ten minutes, and it always costs more in the long run. Getting the mix right from the start, even if it takes longer, is the only way to avoid a total mess later.
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