When the bottom falls out
During some late night casting I pushed the limit on one of my crucibles. I was casting two gold earrings which were proving a little troublesome and thought I could get just one more pour, but in silver, out of the graphite crucible.
Crucibles tend to get ropier with each use and mine finally died when the bottom fell off.
It came off after I dropped in some larger silver pieces into the hot crucible, which turned out to be too fragile to take the strain. I noticed the problem while I was adding the borax and called a halt by turning of the furnace.
A lucky lesson as the furnace was a brand new replacement for my old one of many years – there was no damage to the heat sensor. Whew!