It would be great if someone could invent a web cam that I could put in my kiln. There are times when I really just wonder what the heck is going on in there! I’ve been fusing glass long enough now that I feel pretty confident when I put things into the kiln they will turn out at least close to the way I expect them too. Let’s face it; there are always surprises to be had in the kiln.
But what really gets me is when I do something the same way over and over again, and then out of the blue I get a different result. For instance, I have been using the same firing schedule for my wine bottle cheese boards for a year now. I use the same kiln and the same kiln wash. I always dry my shelves either in the kiln or air dry for a week. Usually all goes well. And then seemingly out of nowhere I get results like the bottle pictured here. This is the bottom of the bottle. It is as if air gets trapped underneath and lifts the glass off the shelf. Very curious! At this point I have two theories.
One theory is that there might be something wrong with one of my shelves. I need to pay closer attention to see if it happens on just a particular shelf. Maybe the shelf is uneven with low spots trapping air that heats up and expands causing the glass to lift. This may be possible, but not very likely.
The other theory is that the glass bottles may be causing the problem. If a bottle isn’t the same thickness all around, might it be possible that heavy sides come down first on to the shelf trapping air which again could lift the glass. Sort of like this:
So if anyone else has had this happen and knows why, please share.