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Stress & Strain & Firing Craziness


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#21 minspargal

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Posted 07 November 2013 - 08:27 AM

I hope all went well with your firing. Want to see pix too!



#22 TJR

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Posted 07 November 2013 - 08:49 AM

Chris;

I can't wait to see how it went. Don't forget to wear gloves.

I am off to teach those lazy Gr 12's. I don't check this blog when I;m working. I actually teach.Ha ha.

Don't forget to wear gloves.

TJR.



#23 Chris Campbell

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Posted 07 November 2013 - 10:52 AM

9:30 am Nov 7 ... Kiln temp is still 431F so I will leave it alone because I have a bunch a glaze tests in there and don't want any confusion over the results.

It turned off at about 1700F into the controlled cooling so I expect to have more cracks in the pieces since it cooled too fast.

I have lots of witness cones inside so I will know what happened on every level.

Luckily it was full of tests ... not a special Christmas Gift or stuff for a big retail show ... :) ... which is actually the time this sort of misadventure usually happens.


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#24 Chris Campbell

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Posted 07 November 2013 - 05:50 PM

WooHoo!! Yes, I opened the kiln and all is good.

Some things worked ... others didn't ... and some are as ugly as a pot can get ... but I got a few beauties too, so all is good.

Middle image shows the comparison between the soda ash wash and glaze ... I much prefer the wash.

No images yet of the experimental works ... the forms performed well and overall I am happy but it is early days yet/.

Lessons come tomorrow when they are cool and results can be analysed.

Putting in an image of what we saw right away ... an element had sprung out and was resting on the shelf. It is totally stretched out so if anyone knows a good way to compress it again without breaking a brand new element, please share!

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#25 Min

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Posted 07 November 2013 - 08:02 PM

Pots look terrific! Wow, were you lucky the element didn't land on the pots, kiln gods were on your side there. (element gods maybe not so much) 

 

For putting an element back in we have always heated it up with a propane torch until it glows orange and then used a piece of wood to gently push it back into the groove. The wood starts to smoke and sometimes catches fire, the element is that hot.  That being said I've never had one come out as much as yours did but I think you could heat up a couple inches at a time and work your way along then staple it in.



#26 Chris Campbell

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Posted 07 November 2013 - 10:42 PM

Thanks Min, I'll give it a try ... Brand new elements that I do not want to break!

Chris Campbell
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#27 Babs

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Posted 08 November 2013 - 12:38 AM

What a journey, well done!

Good luck with the element.

Lovely pots.



#28 Pugaboo

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Posted 08 November 2013 - 08:03 AM

Those are some pretty bowls! Am I right in guessing that the bowls are inside another form to help hold their shape?

Terry
The world is but a canvas to the imagination - Henry David Thoreau

#29 Chris Campbell

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Posted 08 November 2013 - 11:11 AM

Yes, they are to stop slumping ... Although the free standing ones came out OK this time.
I am really going to have to study this firing as there were a lot of new things that happened ... And old things that didn't. For instance ... Nothing warped or cracked ... For my porcelain this is truly unexpected. So is the trick to fire, crash, fire again, crash again?? Who knew?

Chris Campbell
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#30 Babs

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Posted 08 November 2013 - 04:27 PM

Won't read that in any books!!!

Great to share your firing.

Wouldn't advice repeat performance unless you're one of the few totally calm persons

 



#31 PeterH

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Posted 08 November 2013 - 05:47 PM

Chris, Middle image shows the comparison between the soda ash wash and glaze

Pleased all came out well in the end. Could you be a bit more specific about which is the soda ash wash and which is the glaze

Regards, Peter



#32 Chris Campbell

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Posted 08 November 2013 - 06:43 PM

The satin finish is the wash and the shiny one is glaze. I prefer the more subtle satin finish for my work.

 

Before anyone asks:

 

4 parts HOT water to 1 part soda ash ... only make as much as you need for each session.

On my work - one coat is very subtle, two is the finish in the picture and three coatings looks like a clear glaze.

 

***DO NOT PUT LEFTOVERS DOWN YOUR DRAIN AS IT TURNS INTO A SOLID MASS YOUR PLUMBER WILL LOVE. $$$

 

BIG Thanks to Marcia Selsor and Dannon Ruddy for their input on this soda ash wash.


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#33 Pugaboo

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Posted 08 November 2013 - 06:53 PM

I too prefer the soda wash very soft looking.

T
The world is but a canvas to the imagination - Henry David Thoreau

#34 Bob Coyle

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Posted 08 November 2013 - 07:43 PM

 

This may be far afield,  But do any of you know if I can substitute alumina oxide for aluminua hydrate when making kiln wash  using that and calcined kaolin at  a 50-50 ratio?

Vivajones...

 

Yes it is pretty far afield but the short answer is "probably".

 

Alumina hydrate loses water to become alumina oxide when you heat it . There are a million formulas for kiln wash, most of them work.



#35 Bob Coyle

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Posted 08 November 2013 - 07:52 PM

 

It is totally stretched out so if anyone knows a good way to compress it again without breaking a brand new element, please share!

.

Chris... The only way to do this is slowly. Heat small sections of the stretched out element with a propane torch. When they get red hot squeeze them together to shorten them with a needle nose pliers. Keep doing this from one section to the other till you can get it back into the groove. Never try to bend cold elements. They will just snap.



#36 pattial

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Posted 11 November 2013 - 02:24 PM

Love how your bowls have a 'folded" effect. What kind of bowls are you using to prevent slumping? Being fairly new at this I've never seen this before

#37 Chris Campbell

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Posted 11 November 2013 - 02:32 PM

Love how your bowls have a 'folded" effect. What kind of bowls are you using to prevent slumping? Being fairly new at this I've never seen this before

 

Over the years I have tried many types of forms to support outward leaning shapes ... some of those are made with castable refractory ( not worth the work I finally figured out ) and others are simply bowls I throw out of a Cone 10 - 12 clay that I keep re-using until they crack and fall apart ... at which time they then become yard art. I only fire my porcelain to about Cone 8-9 so it works out well.


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#38 Chris Campbell

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Posted 21 November 2013 - 12:02 PM

Sorry ... I just got around to photographing some of the load yesterday. It has been very busy around here!!

I was quite happy with most of the results, some adjustments here and there.

Attached Files


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#39 Marcia Selsor

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Posted 21 November 2013 - 12:34 PM

I like that satin wash. It adds depth to the color without being shiney.

Nice work. What was that dark section on the left on the element that came out of the groove. looks like a glaze booger.Not nice.

Marcia

#40 oldlady

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Posted 21 November 2013 - 02:43 PM

very nice, chris.  the tiny items remind me of the wonderful "mussels or barnacles" that were in the tampa nceca show.  were you the maker?  i wanted to take a bunch home but restrained myself and only took one.

 

 that section of the element that came out of the corner looks as though it was not evenly stretched.  of course, it could just look that way because the rest of it moved so much.  i put in elements for the first time last year and made sure they were perfect before i did them. (whew! thank you element gods!)  the kiln i killed looks like yours does in three places.  it just sits quietly in its corner waiting for someone to replace the elements someday.  it is only 51 years old so maybe i should retire it and use the space for a spray booth.    hhhmmmmmm good idea!


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