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Something Really Weird Happened ?

clay firing kiln bisque firing

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#1 renenderend

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Posted 12 November 2013 - 12:04 AM

In my co op, we fired one of the students bowls over the weekend and when it was brought out of the kiln it looked like it had this sandy bubble coming out of it with the clay from the outside cracking all around it.

My teacher said she had never seen anything like this in the fifteen years shes been teaching art.

we know it couldn't have been a wet center or some foreign product like plaster stuck inside the clay, because that would usually crack or shatter.

I also included a photo of what it looked like when the student cleaned off the sandy bubbles and cracked clay, It was hollow underneath the outside layer of clay.

Also, the brown parts of it felt like a very soft sand. So if you have any idea of what it could have been, we'd really appreciate knowing what happened so we can avoid it happening with more important projects

 

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#2 Mark C.

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Posted 12 November 2013 - 01:17 AM

Something foreign burned out of the clay that no one knew about-it was not plaster

if you have some of that same clay cut it in small pieces with a wire looking for other stuff in it

No telling what it was?

What clay was this? and what temp was it fired to?

Mark


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www.liscomhillpottery.com

#3 Marcia Selsor

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Posted 12 November 2013 - 09:04 AM

It almost looks like portland cement got in there.
Check with the maker to see where they had the clay. Hopefully the class source isn''t contaminated.

Marcia

#4 TJR

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Posted 12 November 2013 - 06:42 PM

Could be a throwing sponge or a chamois. Do you guys say chamois? Weird word.

TJR.



#5 phill

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Posted 13 November 2013 - 02:57 PM

It could also be a low-fire clay accidentally mixed into a high-fire clay, which then bubbled out because it turned into a "glaze."

#6 annekat

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Posted 14 November 2013 - 11:49 AM

Could the piece have been made of recycled clay? All group studios I've worked in have had recycle bins which were available to everyone. It was fairly common for foreign objects or stuff to get in there. Even in my own recycled clay, I occasionally find a chamois or a clay bag closure wire.

 

TJR, I say "shammy". Doesn't matter anyway, because I work alone. But when teaching, I informed students of the correct French pronunciation and the fact that it means "goat" or "goat skin", I think, but that it is OK to say "shammy" because that is what everyone says. Anyone may correct me on the literal meaning of the word. I took a lot of French in school but it was 45 years ago.


Anne

#7 Marcia Selsor

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Posted 14 November 2013 - 12:07 PM

I think Chamois are actually a mountain goat found in the Peaks of Europe in Spain and probably other places in Europe like the Pyrenees. I say "shammy" too. And I use them.
If that accident was from a high fire , it could be some low fire clay as previously mentioned.
Somebody in the shop should solve this before there are many more catastrophes.

Marcia

#8 timbo_heff

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Posted 14 November 2013 - 12:49 PM

I believe the correct pronunciation is Sham-wow .(;



#9 Benzine

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Posted 14 November 2013 - 01:13 PM

It's only pronounced "Sham-Wow" if you are using it to soak up two liters of cola from a carpet.
"Anything worth believing, is worth questioning"

#10 Babs

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Posted 14 November 2013 - 10:53 PM

Primarily used for, soft linings for shoes and clothes, cleaning windows and glass till potters grabbed it.

Certainly from the Chamois, could even be a french canadian word!!



#11 bciskepottery

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Posted 14 November 2013 - 11:00 PM

It's only pronounced "Sham-Wow" if you are using it to soak up two liters of cola from a carpet.

 

Or from the bottom of your pot if you throw using way too much water. 



#12 Benzine

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Posted 15 November 2013 - 11:26 PM

 

It's only pronounced "Sham-Wow" if you are using it to soak up two liters of cola from a carpet.

 

Or from the bottom of your pot if you throw using way too much water. 

 

You gotta be careful with that though.  The Sham-Wow is so absorbant, that if you leave it in there too long, it will suck all the moisture out of the clay.  Heck, I guarantee that you can bisque a ceramic object at room temperature, just by wrapping it with a Sham-Wow.  It will even suck out the chemically bonded water!


"Anything worth believing, is worth questioning"





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