Earthenware clay bisque fired to 04 with a 5 min hold and a 6hr preheat at 200°.
Witness cone shows a good 04 firing.
We use an electronic L&L kiln and have been over firing a half a cone lately which we like the results of but could that “error” cause the preheat to be actually hotter than 200 and over 212° and caused the explosion if that’s what this is. The tile turned to rubble.
The tiles seemed dry but our humidity has been off the charts so who knows.
Any help would be appreciated.