Today I melted some copper in a last time use crucible which had a crack. When it was molten, I took the crucible out but it broke apart and the copper flowed into the furnace AND INTO THE BURNER TUBE:-( Grrr :-((( Fornace repair is rather easy (remove the frozen metal and patch it), but the burner is destroyed as copper flowed into the burner tube. So with repair of the furnace I make a depression at the burner entry so metal can flow there. But I have learned: the smallest crack renders the crucible useless. I can use the bum of the crucible for a plinth replacement which works very nice.
Having never experienced a crucible failure I would imagine it's a mad scramble when that happens, especially with copper temps. That's going to be a big depression to hold a crucible of metal.
