Not The Usual Problem With Glazes On Bisque

[Encorecareer]

I've looked everywhere and talked to several supposed experts. No luck on this one.

 

Just sticking my toe into glazing bisque. Oh don't laugh. I really can paint, but the materials are new to me. Here's the story:

 

Two years ago I bought some tiles, Duncan glazes and clear glaze and took a wack at it. First set perfect. Second set perfect. Third set the top glaze was uneven, showed brush marks and had pitting. I threw my hands up in disgust. Christmas this year I thought I might make something for my mother. Glazed up a beautiful bowl. All the while in the back of mind thinking I could do a series of pieces to try out this year along with my paintings at the fairs and such. Same problem with the glaze occurred. After much consultation and sample tiles with the offending glazes, we realizes that after the second set I had gone out to get more white underglaze and purchased Duncan cover coat white. Originally I had Duncan Concepts. We did a tile test and the cover coat came out powdery thus ruining the final product. OK fine.

 

Next I decided to go ahead and do a cookie jar for my brother's birthday because he collects them. I used the Duncan Concepts undercoat. The Duncan concepts colors and then, oh so carefully, applied the clear glaze. Well the white areas came out perfect, the color areas all have little bumps. The company that sold me the glaze suggested I only use two coats instead of three. Unfortunately I need good solid colors, not tints. I swear it was smooth as a baby's bottom when I put that glaze on.

 

That's my story and I'm sticking to it. 

 

On another note, I've been looking around your community. It's amazing how much you need to know to be a ceramic artist. It must be a lifetimes work just keeping up with the materials and new techniques. Fun! So impressed. You all must be very patient. Probably a good sense of humor helps.

 

[neilestrick]

What clay body are you using, or are you buying bisque? What cone are you firing to?

[MatthewV]

I believe the heart of your problem is simple: the liquids you are using are getting dryer with time. Try adding a little water.

[High Bridge Pottery]

Back when I was starting out I painted a whole kiln load of bisque with a stain and then glazed over the top. All came out with bumpy colours. I think it is because there is too much colouring oxide for the glass to stay glassy.

 

Have you tried one and two coats and know they don't achieve the colour you want? If it is bumpy your three coats may be thicker than their three coats.

 

Could also possibly be over fired.

[GiselleNo5]

Joel, I spent two hours glazing a teapot my youngest sister gave me that she bought from Bisque Imports. It was the Really White and the Dark Delft. The delft blue came out glossy for the most part but the white sort of "soaked in" to the teapot and pitted horribly to the point that it was unusable inside and out. I even refired it with another coat of clear. It was totally unable to be sold despite the work and I gave it to my oldest sister who is now using it as a garlic storage pot. It was very, very frustrating because otherwise I loved how the design came out. I think there was a fault in the bisque ware that caused it because I've never seen these results before or since. 

 

http://community.ceramicartsdaily.org/gallery/image/6971-bisque-imports-teapot/Zoom in and tell me if that's what yours looked like. 

[High Bridge Pottery]

No it wasn't like that, the colour was the dry bumpy stuff and the glaze was fine.

[neilestrick]

What cone is it fired to? What firing schedule?