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Bisque With Low Fire Glaze?


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#1 Biglou13

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Posted 21 July 2014 - 08:00 PM

I'm looking for scholarly source of. Why you shouldn't bisque and low fire glazed wares at same time. Or at least some one scholarly saying it. Or the science of why not published somewhere.

Thanks in advance
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#2 Babs

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Posted 21 July 2014 - 09:14 PM

Don't know if "shouldn't" is a scholarly term!



#3 Tyler Miller

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Posted 21 July 2014 - 10:40 PM

I thought the only reason why it wasn't done was the inefficiency of keeping your bisque well-spaced.  I know the old European updraft bottle kilns sometimes had bisque on the top, glaze on the bottom.

 

But I don't know, is there another reason?



#4 Mark C.

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Posted 22 July 2014 - 01:38 AM

Off gassing of orgainics(from greenware) can affect some glazes other than exploding greenware thats all I got to say .

I have done low fire but it was in the early 70's and was on another planet.

Mark


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#5 Babs

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Posted 22 July 2014 - 02:49 AM

This was discussed in a recent post. Apparently the off gassing/ effecting glazes is not so important now. Only danger seems to be with teh greenware being fired too fast and not surviving, messing up the g;azed ware.

http://community.cer...e +same +firing



#6 Marcia Selsor

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Posted 22 July 2014 - 07:10 AM

colors can be effected by the off gassing especially red. The gases can turn reds liver color.

 

Marcia



#7 TJR

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Posted 22 July 2014 - 08:19 AM

I bisque and glaze at cone 06 all the time. Bisque in the bottom where elements are cooler. Rather than having two half kiln loads of student work, I put them all together. Marcia is correct. If you have a lot of red or orange glaze, you have to fire separately.

My own work I bisque at cone07, and reduction fire at cone 10 in a gas kiln, so the point is moot.

TJR.



#8 Pots by Char

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Posted 22 July 2014 - 08:54 AM

I have done a bisque and low fired glaze at the same time with some success. I fire the kiln as I would for a bisque..which is slowly. I also make sure the glazed pieces are on their own shelf in the kiln to minimize any exposure to off gasing. So far I have not had any problems doing it this way.

#9 Benzine

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Posted 22 July 2014 - 09:02 AM

 .I have done low fire but it was in the early 70's and was on another planet.

Mark

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I occasionally fire my low fire bisque and glazeware together.  I have actually done it less and less, over the years.  It seems that every time I try, there is a piece being bisqued, that explodes, and sticks to the glazeware.  No matter how much I try and dry the wares, and even putting the bisqueware on the bottom/ glaze on top, it just seems to happen.  It's probably due to the fact, that when I would fire them together, it was because it was then end of the term and I was rushing to get everything done.  

I'll still do it on occasion, if I absolutely have to.


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#10 Babs

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Posted 22 July 2014 - 06:12 PM

This is an excerpt from the above link in reference to the effect of mixed firings in kiln.

"Before the prevalance of encapsulated cadmium stains in red and pink and other such glazes .... the lead based low fire cadmium sulfide (CdS) based reds were susceptible to the sulphur dioxide given off by bisque firing clay. Hence the "admonition"."

best,

........................john






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