Serious question, do we really need to warm crucibles for every single pour?

I've worked in casting for a few seasons now. Sometimes when we're busy, I don't warm the crucibles before pouring aluminum. The parts still turn out okay. My foreman says it's a rule, but I think it's only for big jobs or certain metals. For instance, with brass, I always warm them up. But for aluminum, it seems fine. Am I missing something? I'd like to hear from others who might do the same.

3 comments

3 Comments

hayes.jenny1mo ago

Skipping crucible warm-up for aluminum pours? That's how you get steam pockets and ruined parts. Aluminum may seem forgiving, but cold crucibles can lead to incomplete pours or even cracks. I once had a batch fail because we rushed and didn't preheat. Brass absolutely requires it, but aluminum isn't a free pass. The rule exists for a reason, even on busy days.

phoenixb661mo agoOG Member

Wait, you can skip warm-up on aluminum? That's wild. I'd be too scared of wrecking the whole batch.

stellas561mo ago

But how many times have you actually seen a cold crucible cause a real problem with aluminum? Steam pockets sound bad in theory, but in practice I've seen guys get away with it more often than not. The thermal shock just isn't as severe as with brass. Maybe it's more about the specific alloy or the mold temperature being the real culprit.