A batch of cullet from a supplier in Toledo nearly ruined my kiln

Last week I was pulling a set of tumblers from a 1300 degree anneal when I saw a weird, milky haze on the inside of the kiln bricks. I traced it back to a 50-pound box of clear cullet I bought three months ago from a new supplier. The stuff looked clean, but it must have had some kind of contaminant, maybe a trace metal or a bad batch of old glass. It didn't show up in the initial melt, but after repeated firings it started to vaporize and coat everything. I had to shut down for two full days to do a deep clean and a burn-out cycle. Has anyone else had a supplier issue where the problem only showed up after a while?

3 comments

3 Comments

the_kim14d ago

Ugh, did you test the cullet first?

harper_foster14d ago

I used to skip testing new cullet, but a similar mess changed my mind fast.

the_lee13d ago

Hate how everything seems fine until it's not. You see it with cheap parts for my old truck and now with your glass. The slow, hidden failure is always the worst kind.