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Kiln Sitter Problem


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#1 jtlnickerson

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Posted 21 March 2013 - 09:37 AM

In my last firing the kiln sitter malfunctioned resulting in an over-fire. I used an 06 cone that ended up as a black blob stuck to the sitter and the majority of the works ended up stuck to the shelves due to glaze run off. For the most part everything seems okay, some of the colors are a little funky but nothing too bad. Could this have been the result of a faulty cone or is the sitter to blame? What are some recommendations for me to a.) get the remnants of the cone safely off the sitter, and b.) get the work off the shelves without too much damage. Thanks in advance!
"Painting is easy when you don't know how, but very difficult when you do." - Edgar Degas

#2 potterbeth

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Posted 21 March 2013 - 10:06 AM

How many firings have you done on the kiln sitter? Chances are that your kiln sitter rod is not moving freely inside the tube during the firing...so it isn't moving downward as the cone melts resulting in the mess on the sitter and on your shelves. Sometimes this is caused by debris that has worked its way into the tube, but usually it's due to corrosion. Turn off/unplug your kiln and try moving the kiln sitter rod with your finger, noting any resistance. Then blow hard through the hole holding the rod from the outside of the kiln. Try moving the kiln sitter rod again, noting if there is any change. In my experience, if the kiln sitter is binding, it's even worse when the kiln is hot. If I were you, I'd replace the kiln sitter tube.

#3 jtlnickerson

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Posted 21 March 2013 - 11:49 AM

How many firings have you done on the kiln sitter? Chances are that your kiln sitter rod is not moving freely inside the tube during the firing...so it isn't moving downward as the cone melts resulting in the mess on the sitter and on your shelves. Sometimes this is caused by debris that has worked its way into the tube, but usually it's due to corrosion. Turn off/unplug your kiln and try moving the kiln sitter rod with your finger, noting any resistance. Then blow hard through the hole holding the rod from the outside of the kiln. Try moving the kiln sitter rod again, noting if there is any change. In my experience, if the kiln sitter is binding, it's even worse when the kiln is hot. If I were you, I'd replace the kiln sitter tube.


The sitter appears to be in good condition. I'm not 100% but I believe that it was replaced within the last year or two, and I have used it on multiple occasions without issue. Right now the rod can't be moved because the cone melted to it, so I can't be certain if there is any other obstructions. Thanks.
"Painting is easy when you don't know how, but very difficult when you do." - Edgar Degas

#4 neilestrick

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Posted 21 March 2013 - 11:56 AM

Sitters malfunction. It's not uncommon. Do you have a backup timer on the sitter?

If the rod is fused to the ceramic tube, replace them with a new tube assembly. You'll never get them clean enough to work safely. If the rod is fused to the cone support bars, replace the rod and bars. You can try grinding them, but any glaze remnants can cause sticking in the future. Don't grind so much on the rod that it gets narrower as that will affect it's function.
Neil Estrick
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Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com

#5 missita bonita

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Posted 21 March 2013 - 12:41 PM

This happened to my kiln sitter also. I used a wire cutter tool and cut the blob on one side. Then it all fell off and was not melted to the rod. It just appeared that way, but it came off clean. Good luck!

#6 jtlnickerson

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Posted 21 March 2013 - 01:27 PM

Sitters malfunction. It's not uncommon. Do you have a backup timer on the sitter?

If the rod is fused to the ceramic tube, replace them with a new tube assembly. You'll never get them clean enough to work safely. If the rod is fused to the cone support bars, replace the rod and bars. You can try grinding them, but any glaze remnants can cause sticking in the future. Don't grind so much on the rod that it gets narrower as that will affect it's function.


The timer was on, probably prevented serious damage. The cone is only stuck to the rod, it appeared to be on the support bars but popped right off when I wiggled it. it's about 1/4 inch from the tube. Thanks
"Painting is easy when you don't know how, but very difficult when you do." - Edgar Degas

#7 Pres

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Posted 21 March 2013 - 01:48 PM

In my last firing the kiln sitter malfunctioned resulting in an over-fire. I used an 06 cone that ended up as a black blob stuck to the sitter and the majority of the works ended up stuck to the shelves due to glaze run off. For the most part everything seems okay, some of the colors are a little funky but nothing too bad. Could this have been the result of a faulty cone or is the sitter to blame? What are some recommendations for me to a.) get the remnants of the cone safely off the sitter, and b.) get the work off the shelves without too much damage. Thanks in advance!


I had a setter that was installed over two sections of the kiln in an older L&L kiln. The upper section got out of alignment so that the setter was setting at an angle-not visually perceptible, but close attention to the swing bar would show that it leaned in to far to drop the 180 degrees to turn off the kiln. Big mistake, as it overfired, but luckily I timed my setter to within 30 minutes of the time needed to reach temp. Lesson here is to always check the swing bar for freedom of movement. Another thing is to check to make certain that the catch rod is freed up also.

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#8 neilestrick

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Posted 21 March 2013 - 02:37 PM

Also check to make sure the sitter rod is straight. A bent rod can cause over firing. And calibrate the sitter.
Neil Estrick
Kiln Repair Tech
L&L Distributor
Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com




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