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Why did my crucible crack mid-pour today?
Poured a batch of aluminum this morning at the shop near Pittsburgh and the crucible just split right at the bottom, sending metal everywhere. It was a brand new silicon carbide one I only used about six times. Anyone have this happen with a newer crucible before?
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brian_jackson5mo ago
That reminds me of something that happened at a buddy's uncle's farm near Erie like fifteen years ago. He was casting something, I forget if it was aluminum or maybe even lead for fishing weights, and the crucible just gave out with a hiss and a spray. Turned out he had set it on this old wooden workbench that was soaked in linseed oil from years of tool cleaning, and the heat from the crucible bottom caught the whole bench on fire while he was pouring. The crucible didn't even crack first, it was fine, but the whole shop almost went up because of what was underneath it.
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derek_dixon785mo ago
Yeah that moisture thing, I started preheating my crucibles slow on low heat for an hour before anything goes in and never had a crack since.
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karent755mo ago
Happened to a buddy of mine over in Youngstown last year. He was pouring brass and that same kind of crack split right up the side on his fourth use. He was pissed because the crucible looked fine before he heated it up, no chips or anything. Turns out he had it sitting on a damp concrete floor overnight before the pour and the moisture trapped in the material just exploded when it hit temp. That little bit of water from the humidity or a spill can get into the silica and wreck it fast. Now he always stores them on a rack with a heat lamp nearby, never had the problem since.
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