UNDERGLAZE ON KENTUCKY MUDWORKS BROWN BEAR CLAY

[Valarie]

Does anyone have advice on underglaze on dark clay bodies before the bisque firing??  I am using KM Brown Bear and I want the glazes to pop more. 

I have read that you can apply white slip or white underglaze  before the piece is bisque fired.   Are there any potential issues with this? I  am worried that the final glazing will peel/ react  or just look like  trash .. And as usual , I want  to try something new when time  is of the essence  as the piece is a gift .

[Bill Kielb]

Like most in clay, both can work and both can have compatibility issues. Unfortunately testing all together (including your glaze) is the only solid advice I can give.

[Valarie]

Thank you for the response . I went for the underglaze ,see how it comes out. If it works I will post a pic, if it doesn't  I'll just describe the disaster.

[Babs]

@Callie Beller Diesel does this. She may reply here.

Slipware artists do this all the time. Slip and body shrinkage has to ve compatible and applied to work at a certain dryness, but all doable.

 

[Callie Beller Diesel]

I use Plainsman M390, and frequently do a white stoneware slip if I want a colourful, translucent glaze to pop. As long as your slip shrinks at the same rate as your clay body, you’re golden. There are lots of white slip recipes out there, and using a white slip over a terra cotta clay body to create a decorating background is a very common practice. Joan Bruneau comes to mind very quickly, and so does Ben Carter, who does the Red Clay Rambler podcast if you want to google for some lovely examples.

I buy dry bags of M370 casting slip (same as the throwing clay, but without the bentonite) for my white decorating slip. It’s got the same shrinkage rate as the red, and I only have to add water to it. If I want to do textural work, I just mix it thick. If I want to have a clean surface for decorating, I have just brushed it on in the past, but I found I liked the smooth look of poured slip, so I do have a bucket that I’ve added some darvan to.

I did find early that I have to carefully watch when I apply my slip, because my clay body is very susceptible to readsorbtion. Your clay may or may not react this way. It’s something to keep in the back of your mind.  If it’s something you’re interested in, I can elaborate, but I don’t want this post getting too long if you’re not.

I found when I was using coloured underglazes with a clear coat, if I didn’t bisque the ones I was using before applying glaze, the glaze didn’t absorb well over the UG. Even after bisquing, the pigment itself was a little like terra sig. It was really finely packed,  and absorbed better, but not as much as the bare clay did. I was using Mayco brand, so other brands may be different. I also use dipping glazes I mix myself, and if you’re using brush on ones, this may be less of an issue for you.