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My confusion over why the bronze pour hissed like a snake
During a bronze pour last week, the metal started hissing loudly when it hit the mold. I thought something was wrong, but my foreman just laughed and said it's normal with damp sand. Now I'm curious why moisture causes that sound, and if it affects the casting quality. It still jumpscares me each time it happens.
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burns.grace7mo ago
Oh that hiss will get you every time. It's just steam from the moisture in the sand flashing off instantly. The trouble starts if there's too much dampness, or poor venting. That steam has to go somewhere, and if it gets trapped it can leave pits or even blow metal right out of the mold. Always makes me flinch a bit too, even when I know it's coming.
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jenkins.richard7mo ago
Yeah but how bad can it really be? I've seen some pretty soggy sand casts and yeah you get that scary hiss and maybe some surface pitting, but I've never seen one "blow metal out of the mold" like some people claim. Sounds like shop floor ghost stories to me. Most of the time it's just noisy and makes a mess, not like it's gonna wreck the whole piece.
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kelly.robin7mo ago
That hiss is no joke. We had a real bad blowout once from wet sand. Scared the hell out of everyone. Started ramming our molds bone dry after that. Takes longer but the castings come out clean. No more steam pockets or surface junk. Worth the extra time for sure.
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