GEP Posted May 6, 2011 Report Share Posted May 6, 2011 Here's a question for the electric kiln gurus. In the past 2 weeks I've had two elements in my kiln burn out. Both lived for less than 60 firings. I'm wondering if this has anything to do with an incident that occurred about a month ago ... one of the element lead wires for my middle zone burned out (probably not tight enough) therefore the kiln fired to cone 6 using just the top and bottom zones. I'm pretty sure it only happened once, my firings are usually very predictable and this was the first sign of trouble. A few weeks later, one of my bottom zone elements died. Upon inspection, the elements in the top and bottom zones looked terrible (distended, crooked, very powdery) while the elements in the middle zone looked pretty good (tightly coiled and straight, not very powdery). And now one of the elements in the top zone has bitten the dust too. So my question is ... can one cone 6 firing, where the top and bottom zones do all the work, cause so much stress to those elements that they could die prematurely a few weeks later? Mea Link to comment Share on other sites More sharing options...
DAY Posted May 7, 2011 Report Share Posted May 7, 2011 Is it a "cone 10" kiln, or a low fire (cone 6) model? Computer controlled or kiln sitter? How old is the kiln- are these the original elements? 60 firings could be many years for a "hobby" kiln, 20 weeks @ 3 times a week for production. Link to comment Share on other sites More sharing options...
GEP Posted May 7, 2011 Author Report Share Posted May 7, 2011 Is it a "cone 10" kiln, or a low fire (cone 6) model? Computer controlled or kiln sitter? How old is the kiln- are these the original elements? 60 firings could be many years for a "hobby" kiln, 20 weeks @ 3 times a week for production. This is an L&L easy-fire, computer controlled with three zones. Built to fire to cone 10, but I glaze fire to cone 6. Not the original elements ... these elements were installed last summer. I have a one-person production studio, so I fire about 6 times per month. Mea Link to comment Share on other sites More sharing options...
Marcia Selsor Posted May 7, 2011 Report Share Posted May 7, 2011 I read an analysis of element life by Linda Arbuckle that was interesting. She posted the different life spans depending on the temperatures fired. These are just numbers I am making up to illustrate what she said. It went something ilk this: 590 firing for bisque 300 for ^6 glaze There were significant differences. ALso if you are firing down for a slow cool , you will probably shorten the element life. If you have a sulfurous clay body or use glazes that burn off certain chemicals, that would also shorten your element life. If you protect your elements with a coating of ITC for metal, you may extend the element life. Marcia Link to comment Share on other sites More sharing options...
bciskepottery Posted May 7, 2011 Report Share Posted May 7, 2011 Your connection problem with the middle elements may have caused the top and bottom elements to heat higher and compensate for the middle elements -- perhaps to the point of weakening them enough to burn out. Your electric controller monitors the temperature readings of the thermocouplers and tries to keep them in sync. If one is not firing, because of the loose connection, the others may fire hotter to compensate. If the difference becomes too great the kiln usually shuts down with an error code (those running on computer controllers). I'm sure Arnold Howard can explain it better and more technically. We just had a situation at the studio where one of the relays became stuck, resulting in the middle elements heating much too fast and the top and bottom could not make up the difference. It was an L&L Easy Fire. Got ERRD. I turned off the kiln at the controller box not realizing the relay was stuck. It continued to fire even though the controller was off -- the runaway kiln syndrome. Link to comment Share on other sites More sharing options...
DAY Posted May 8, 2011 Report Share Posted May 8, 2011 Since it is an L&L kiln, call, talk to Eric. Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 9, 2011 Report Share Posted May 9, 2011 Here's a question for the electric kiln gurus. In the past 2 weeks I've had two elements in my kiln burn out. Both lived for less than 60 firings. I'm wondering if this has anything to do with an incident that occurred about a month ago ... one of the element lead wires for my middle zone burned out (probably not tight enough) therefore the kiln fired to cone 6 using just the top and bottom zones. I'm pretty sure it only happened once, my firings are usually very predictable and this was the first sign of trouble. A few weeks later, one of my bottom zone elements died. Upon inspection, the elements in the top and bottom zones looked terrible (distended, crooked, very powdery) while the elements in the middle zone looked pretty good (tightly coiled and straight, not very powdery). And now one of the elements in the top zone has bitten the dust too. So my question is ... can one cone 6 firing, where the top and bottom zones do all the work, cause so much stress to those elements that they could die prematurely a few weeks later? Mea, where did the elements burn out? At the connectors? Somewhere in the groove? Have you had elements burn out in the same place as the previous elements? Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
GEP Posted May 9, 2011 Author Report Share Posted May 9, 2011 Here's a question for the electric kiln gurus. In the past 2 weeks I've had two elements in my kiln burn out. Both lived for less than 60 firings. I'm wondering if this has anything to do with an incident that occurred about a month ago ... one of the element lead wires for my middle zone burned out (probably not tight enough) therefore the kiln fired to cone 6 using just the top and bottom zones. I'm pretty sure it only happened once, my firings are usually very predictable and this was the first sign of trouble. A few weeks later, one of my bottom zone elements died. Upon inspection, the elements in the top and bottom zones looked terrible (distended, crooked, very powdery) while the elements in the middle zone looked pretty good (tightly coiled and straight, not very powdery). And now one of the elements in the top zone has bitten the dust too. So my question is ... can one cone 6 firing, where the top and bottom zones do all the work, cause so much stress to those elements that they could die prematurely a few weeks later? Mea, where did the elements burn out? At the connectors? Somewhere in the groove? Have you had elements burn out in the same place as the previous elements? Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Arnold, the elements burned out within the grooves, not at the connectors. The last time I replaced all the elements (last summer), it was because one of them had broken and burned out in exactly the same way. However, none of the breaks have occurred in the same spot. All three break/burnouts have been in the top or bottom zone, none in the middle zone. I put a photo of one of the breaks on my blog, they all look like this: http://www.goodelephant.com/1/post/2011/04/the-blob-mocks-me.html If you need any more details, just ask! Mea Link to comment Share on other sites More sharing options...
Marcia Selsor Posted May 9, 2011 Report Share Posted May 9, 2011 Mea, The photo was really interesting. The Plate setter connection is an interesting part of the puzzle. Ask a rep from the company and send them a photo. ANother possibility could be chemicals jumping from the glazes. Does that ever happen? Let us know what the rep says. It is an interesting problem and one which many of us could benefit from an answer. Marcia Link to comment Share on other sites More sharing options...
GEP Posted May 9, 2011 Author Report Share Posted May 9, 2011 Marcia asked "ANother possibility could be chemicals jumping from the glazes. Does that ever happen?" I never find any blobs or drips of glaze on my kiln shelves, but as the shelves get older they are developing "freckles" where I think glaze is spattering off of the pots in tiny amounts. I didn't think this could travel all the way into an element groove, but is this possible? This would not explain the recent condition of my elements, which is that the top and bottom zone elements wore out so fast, while the middle zone looks pretty new. But I guess glaze spatter should be on my list of things to be careful about. I should expand on what I wrote on the blog ... when I replaced the bottom zone elements, the top and bottom zone elements looked older than the middle zone, but not by that much. I chalked it up as normal. But since I wrote that blog post, I continued to fire the kiln with new elements in the bottom zone, the top zone elements deteriorated quickly. Every time I opened the kiln, I was like oh gosh they look worse! When the element broke in the top zone, I wasn't that surprised. Mea Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 9, 2011 Report Share Posted May 9, 2011 This would not explain the recent condition of my elements, which is that the top and bottom zone elements wore out so fast, while the middle zone looks pretty new. But I guess glaze spatter should be on my list of things to be careful about. The top and bottom elements are probably turned on a greater percentage of the time than the center elements, because the top and bottom sections of the kiln require more heat than the center section. That would explain why the top and bottom elements wear out faster than the center elements. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
bciskepottery Posted May 10, 2011 Report Share Posted May 10, 2011 In our recent runaway kiln episode, the glaze jumped off a bowl (literally) and splattered on the element holder -- just missing the element. We've also had an incident where a bowl was overhanging the shelf and a glob splattered onto an element. So, yes, glaze splatter is something to watch for routinely. Link to comment Share on other sites More sharing options...
GEP Posted May 11, 2011 Author Report Share Posted May 11, 2011 Thanks everybody, for all the information and suggestions. I feel reasonably sure now that the loose element lead wire connection contributed to the early death of my elements. I also accept that element life is too vague to fully attribute a failure to any one incident. In response to DAY's suggestion, I have been talking to the L&L tech support staff throughout this whole series of events. As much as I adore them, they only have one response to the subject of element life ... that so many factors contribute to element life, it's impossible to know exactly what happened. So I posted my situation on this forum to see if anyone else had the same specific incident as me. I'm glad to have gotten more perspectives about it, but now I'm also prepared to accept that the answer given by L&L is really the best answer. But that doesn't mean this subject needs to end. If anyone else has any thoughts or experiences about element life, both in terms of extending and shortening their life, please share! Here's one ... one of the things L&L said was that adding a 15 minute soak to the end of a cone 6 firing could cut an element's life IN HALF! This really surprised me, as I had always believed that a 15 minute soak was a good thing. Does anyone agree or disagree with this? Mea Link to comment Share on other sites More sharing options...
bciskepottery Posted May 12, 2011 Report Share Posted May 12, 2011 I hold for 15 minutes during glaze and bisque loads; for glaze loads it is to ensure a smooth glaze melt and for bisque it is to ensure the nasties burn out. I'm surprised that doing so would cut element lifespan by half. I also preheat bisque, holding at 200 degrees for 2 hours; would that have a similar effect on element lifespan? Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 12, 2011 Report Share Posted May 12, 2011 Here's one ... one of the things L&L said was that adding a 15 minute soak to the end of a cone 6 firing could cut an element's life IN HALF! This really surprised me, as I had always believed that a 15 minute soak was a good thing. Does anyone agree or disagree with this? The higher the temperature of the firings, the shorter the element life. A 15 minute hold at 1425F during a glass firing will add much less wear to the elements than a 15 minute hold at cone 10. I don't know how much extra wear a 15 minute hold would add to elements at cone 6, because I have never tested element life in that condition. I would guess that adding a 15 minute hold to a cone 6 firing would add only a slight amount of wear to the elements. It depends on the condition of the elements and the kiln's capacity to reach cone 6. A kiln with worn out elements or a kiln that can barely reach cone 6 fires very slowly as it nears the shutoff temperature. That long, slow struggle is hard on the elements. In that case, a 15 minute hold would add more element wear than with a kiln that can easily reach cone 6. If a 15 minute hold improves your firing results, I would definitely add the hold. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 12, 2011 Report Share Posted May 12, 2011 I also preheat bisque, holding at 200 degrees for 2 hours; would that have a similar effect on element lifespan? Preheat adds little wear to the elements, because the temperature is so low. You can tell by the humming sound and the click of the relays that the elements are off much of the time during preheat. The least expensive way to dry greenware is to place it near the kiln as you fire another load. The ambient heat then becomes useful. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
Seasoned Warrior Posted May 12, 2011 Report Share Posted May 12, 2011 I also preheat bisque, holding at 200 degrees for 2 hours; would that have a similar effect on element lifespan? Preheat adds little wear to the elements, because the temperature is so low. You can tell by the humming sound and the click of the relays that the elements are off much of the time during preheat. The least expensive way to dry greenware is to place it near the kiln as you fire another load. The ambient heat then becomes useful. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Residual heat, in engineering terms, Arnold. Perhaps Paragon could include a heat exchanger and a blower with a cabinet as an option to the exhaust sytem to capture that residual heat. Certainly would be a greener system and would reuse some of the calories lost. Regards, Charles Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 12, 2011 Report Share Posted May 12, 2011 Perhaps Paragon could include a heat exchanger and a blower with a cabinet as an option to the exhaust sytem to capture that residual heat. Certainly would be a greener system and would reuse some of the calories lost. Thanks for the idea, Charles. Some people use the residual heat by placing greenware on metal shelves near the kiln. A couple of small fans circulate the warm air. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
Mossyrock Posted May 12, 2011 Report Share Posted May 12, 2011 This doesn't have to do with kiln heating element lifespan, but another replacement part. It has been suggested to me to run a small fan in front of the computer controller during firings to prolong the life of the relay switches. Does anyone else do this and can you tell if it has helped? Link to comment Share on other sites More sharing options...
DAY Posted May 12, 2011 Report Share Posted May 12, 2011 Adding another can 'o worms to this thread, the kind of element makes a difference on their life. My big L&L has the (original) heavy duty elements, and has been fired 340 times since 2004, and the firing time has only increased 10%. I never tried the "coating" that claims to increase element life- anybody? Link to comment Share on other sites More sharing options...
Arnold Howard Posted May 12, 2011 Report Share Posted May 12, 2011 It has been suggested to me to run a small fan in front of the computer controller during firings to prolong the life of the relay switches. Does anyone else do this and can you tell if it has helped? A small fan will lower a kiln's switch box temperature, which can prolong the life of electrical parts. Under most conditions the fan is unnecessary, but the fan is a good idea in hot areas such as Texas during the summer. If parts such as relays keep burning out, the cause could be loose connections, too. A heat-damaged push-on connector can destroy a new relay. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
Guest HerbNorris Posted May 12, 2011 Report Share Posted May 12, 2011 This doesn't have to do with kiln heating element lifespan, but another replacement part. It has been suggested to me to run a small fan in front of the computer controller during firings to prolong the life of the relay switches. Does anyone else do this and can you tell if it has helped? I have a Envirovented Skutt 1027 which I fire in our 20 X 22' garage. We have had one instance of our board getting too hot, and shutting the kiln down. On hot days, the garage will often get above 100º F, so we use a box fan to help cool the board. Apperently the position of the fan can have an effect on the cooling, when we had the overheating problem, I had placed the fan to blow up over the top of the kiln, so as to deflect the heat and hopefully cool. The board overheated, apparently from some type of air circulation pattern that I didn't expect. After restarting the kiln, the board temp again went to 152º F, so I quickly put the box fan on the floor, almost directly underneath the control box. I raised the top of the fan about 6" using a little box, so that the fan was blowing up at a shallow angle, perhaps 25º. The fan was sucking the cooler air near the floor, and pushing it through the bottom louvers. Within ten minutes the board temp had dropped from 152º F to 130º F; I left the fan there for the remainder of the firing. We have fired our Skutt about 200 times between bisque and glaze, and even raku firings, and the firing times have increased somewhat, but who cares? We use all kinds of hold times, five minutes, fifteen minutes, one hour. We are still using our original elements, I replaced the relays when they burned out, and Skutt replaced and shipped em to me overnight free. The kiln is just another tool, and all tools wear out; I bought my kiln to USE to make POTTERY, not to baby around and worry about. Life is too short to worry about kiln parts. As far as coating elements with ITC, this is more trouble than it is worth, in my estimation. It has to be done with brand new elements, you cannot use your present elements. ITC is not cheap. ITC must be sprayed on the elements, and unless you already have spray equipement, you have to get that somehow. then you have to spray the inside of the kiln. Arnold has some great suggestions, and I think L&L is right when they say that many factors enter into element longevity. I say, elements are cheap, and I'm not a millionaire; life is too short, people! Make and enjoy your ceramics! Link to comment Share on other sites More sharing options...
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