My crucible cracked mid-pour yesterday afternoon

I was pouring a batch of aluminum around 2pm yesterday and heard that sound you never want to hear. A crack ran right down the side of my #30 crucible and started leaking molten metal onto the floor. Had to grab the tongs and rush it back to the furnace before it dumped everything. Anyone else had a crucible fail on them out of nowhere or was that just my bad luck?

3 comments

3 Comments

victorhernandez11d ago

The #30 crucible is actually a pretty common size for smaller pours but they tend to have thinner walls than the #20 or #16 so they heat up faster but also crack easier if you get thermal shock. I had a #30 crack on me last summer after I rushed the preheat cycle by about 15 minutes, brought it up too fast from cold and it just gave out right when I started pouring into a sand mold. The worst part was cleaning up the spilled aluminum from the concrete floor, took me an hour with a chipping hammer.

jackson.max11d ago

Damn, that's rough. A buddy of mine had the same thing happen with a #30 last year, ended up with a puddle of bronze setting up on his garage floor and it took him all weekend to chisel it off.

sullivan.quinn10d ago

Actually I was the opposite for a while lol. I used to think the #30 was fine because it heats up faster and I'm impatient, but after reading this and victor's comment I'm starting to think I got lucky with mine not cracking yet. I had a #20 last me years but I always rushed the preheat on it too, never had issues. Now I'm wondering if the thinner walls on the #30 just make it way more sensitive to that kind of thing. I bet the thermal shock is way worse when you're going from cold to pouring temp in like 10 minutes flat like I do sometimes. Definitely gonna slow down my preheat cycle from now on, especially since I don't want to deal with cleaning up a puddle of molten metal off my garage floor.