I didn’t load these three mugs because the light colored glaze didn’t adhere to the piece and will likely come off during firing. Can’t risk it landing on another persons work or the shelves or elements.
To tag onto the message above- We’ve had some recent glaze pieces that have run in the kilns. This is problematic because it ruins community cookies, wears down our kiln shelves, and makes extra work for the kiln team. While the kiln team does their best job of loading pieces, we’ve had ALOT more issues recently.
If anyone has questions about glaze- feel free to PM me - if I don’t know the answer, I can find someone who does. Also, it would be helpful if people could provide their own cookies (especially if your piece is larger than, let’s say a mug). Sometimes there are large cookies available and sometimes there aren’t.
Some form of clay is a common ingredient in most pottery glazes, it is used as a source of alumina to keep the glaze from running too much. I suspect the glaze that is pealing off was from the bottom of a jar. Glazes are a careful balance of ingredients mixed with water, if glaze isn’t mixed well EVERY time before use that balance gets distorted when you come to the end of a jar. Clay is clay, it shrinks a lot when it drys. It’s also a heavy ingredient and settles to the bottom of the jar over time. I’m guessing the percentage of clay was out of balance in that glaze and just shrank more than usual.