LilBlueFrog

The external crazing is minimal but there, and yes its definitely possible that I put it on too thickly. I thought I was buying a stiff clear, but apparently not in this situation. Its good to know that the underglaze will follow the lead of the glaze in terms of movement. Thank you for the help!

Ohhhh cool, thanks for the info! What shape does unmatured clay chip in? Also, are there ways to tell cone 5 vs cone 10 post-bisque? Asking for a friend, ahem.

Ok, thank you so much for the information. Now I have more questions! What is WYSIWYG? I googled it but nothing obvious came up... When you say the glaze and clay body are mismatched, what does that imply, chemically/physically? Is mixing brands an issue because brands might use different flux/stabilization ingredients that may then not play nicely together? This was very helpful, thanks for the detailed reply!

Hi, I've only been doing pottery for a few years, and am trying to learn how to not ruin things with glaze! I made this mug out of B mix that I THINK was cone 5. I applied mayco stroke and coat to the leather hard piece, carved through it, and bisqued it. It looked as I expected, with the underglaze where it was intended to be. There was even a fleck of it that had dripped where I didn't want it, and I could not get it off with sanding. So I felt I could assume the underglaze was well fused to the clay body. The handle was originally without underglaze but I decided I wanted it purple as well, and figured then I'd get to see the difference between stroke and coat on greenware vs on bisque. I then applied 1 dip coat of Coyote Clear MBG007-P and fired to cone 5/6 (don't know which exactly, my clay supplier fires things for me). I did not expect the glaze and underglaze to interact, I did not expect the glaze to run, and I did not expect the glaze to craze, but all of these things happened (the running I am basing on the fact that it stuck a little to the kiln shelf). The difference between underglaze on bisque vs greenware was unremarkable, both gave a mottled watercolor effect. It's pretty, but what happened? Could this be a result of this clay actually being cone 10? Perhaps it crazed because I applied it too thickly? I am more of an organic chemistry person, but inorganic is certainly prettier, and I am excited to learn things from you all!

I have definitely applied underglaze too liberally around the base of a greenware handle attachment point, and after bisque that attachment had released. Interestingly, after glaze firing the clay shrank in a way that brought the handle back to the body, and the glaze fused them back together.