Glaze crazing! Please help!

[PotteryLodge]

Sorry for all the questions, but this is only year 2 of making ceramics so I'm learning as I go and really appreciate the support : )

I have been using the same clay,slip and glazes purchased from a local ceramic shop. Everything has turned out beautifully but I got a new mug mold that will NOT stop giving me issues!

The mug is slip cast using low fire slip. I fire to bisque..all good. Then I apply my glaze and fire..I let the kiln cool for at least 12 hours and still around the rim and handles I keep getting light crazing. No matter what I do..less glaze, more glaze, longer firing, soaking on high, the mug will still craze. Keep in mind, I haven't changed anything from the other ceramics I'm glazing, which all turn out without crazing, just the mugs are crazing. It's weird and I can't seem to figure out why or what I can do to keep this from happening.

Thanks again!
-Casi

[barbaradonovan]

Hi Casi,
Crazing is mainly caused by a fit problem between the glaze and the clay. If you're using commercial glazes and commercial greenware, you have no control over this because you can't adjust the recipes yourself. Only the manufacturers who make them can. The best you can do is try another brand of greenware or glaze. Trying another brand of glaze might be the easier first step but could get expensive since you don't know what will work until you buy it and test it.

If your supplier makes the slip themselves, you may mention the problem to them. If enough people have this problem, they may decide to adjust their slip recipe.

Here is a link to a Ceramic Arts Daily article on glaze flaws. You might read the comments area too because sometimes people have suggestions that are helpful.
http://ceramicartsdaily.org/ceramic-glaze-recipes/glaze-chemistry-ceramic-glaze-recipes-2/how-to-cor...

Good luck!
-b

[PotteryLodge]

Thanks Barbara. I bought some new glaze yesterday and will just have to see if it works better. Such a bummer trying to figure this stuff out : (