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Can Goldart Sub For Ball Clays Or Kaolin In Glazes?


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#1 enbarro

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Posted 15 February 2014 - 11:25 PM

Hi, some years ago I got 5# of gold art because I was intending to fire cone 6 (Zakin's electric kiln book recipes). That is yet to happen.

 

Can I used it instead of ball clay or kaolin in lowfire glazes?

 

I know how to use a calc program...  but I read that is has higher levels od sulphur. Is there any other thing I should keep in mind before I try it?

 

 



#2 neilestrick

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Posted 16 February 2014 - 08:16 AM

I wouldn't do it. Goldart is a stoneware clay. The particle size may not be consistently small enough, it does have more sulphur than most clays, the iron content is higher than kaolin so it will darken you glazes a bit, and it matures at a lower temp.
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#3 Marcia Selsor

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Posted 16 February 2014 - 08:28 AM

I agree with Neil about the high sulphur content in Goldart. I did have a simple glaze using part gold art and dolomite and something else for ^10 reduction. Haven't used it in decades.

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#4 TJR

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Posted 16 February 2014 - 12:04 PM

I've got a bucket of Goldart sitting in my studio. Haven't used it in decades. We used to have a white slip for cone 10;

Schiller White Slip

EPK         33

Ball Clay  33

Goldart    33

I don't use white slip any more, I just use a white clay body.

I also have heard that you could make a Cone 6 clay body with 50 Goldart and 50 Redart. Never tried it though, so test,test,test.

I want to try Marcia's ash glaze recipe for cone 10-50 Goldart, 50 Ash,

But I already have a good ash glaze.So there the bucket of Goldart sits, unused, and unloved.

TJR.



#5 Colby Charpentier

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Posted 16 February 2014 - 11:38 PM

If you have a glaze calc program, it'll be comparing the UMF of each material to determine what specifically the gold art is providing to the mix. A simple 1 to 1 substitution would end up likely leaving you with an improperly formed glass that will deteriorate over time (and be unsafe especially with more "active" colorants), assuming it manages to function aesthetically. The best solution would be to try a slip or ash glaze or shino, where the glaze science is imbalanced anyway. These tend to be most effective in atmospheric firings, where you're providing additional fluxes to melt out the abundant glass former. Another consideration is making small batches of clay bodies like TJR mentioned. In this case, I would try colored clay bodies (because that's what exites me, and that's what I'm currently working on). The caution as far as clay bodies go is that you'd want to make sure you have a good maturity temperature and good working qualities. the glaze calc program can help you with most of that, and the rest is going to be using good binders like a bentonite or otherwise.

 

Good Luck!



#6 enbarro

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Posted 18 February 2014 - 10:08 PM

Thanks. I'm going to leave it for experimental textured glazes...






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