Hi Gregg and fellow potter,
Some time when you have extra space in you kiln throw one of them "porcelain" or are they ceramic
tiles in and see if they melt. I would be curious to know at what cone. My guess is they are fired below cone 6. Just a guess. I will have to read the info from John B. friend from OZ. Maybe he mentions the temp they fire tiles. I skimmed the report but will need to take the time to read it in detail this p.m.
I think I laid the Dahl tiles in 2000 and that was before I had a digital camera. I threw the molten tile out in one of my cleaning fits at the studio but for giggles I will fire one the next time I fire a bisque (to ^05) and then another tile when I fire the dragon to ^10 Reduction. I will send a picture of the results.
If you do the test, don't forget to fire the tile on a dish with a lip or in a bowl just incase it will melt which I am going to bet it will. Don't want a ruined kiln shelf.