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Two kilns and one pyrometer all break at once - coincidence or related ?


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#1 Isculpt

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Posted 09 December 2012 - 12:04 AM

First, I have to confess that I am "mechanically dyslexic". Regrettably, I simply am no good at diagnosing, let alone repairing, mechanical or electrical equipment. I own one analog pyrometer, which I switch between the two kilns as needed, and two manual electric kilns, all oldies but goodies until now.

In the same week, I used both kilns with no trouble. Then I took the probe out of the larger kiln and put it into the smaller test kiln, only to discover that the test kiln simply wouldn't start. A few days later I moved the probe to the larger kiln, fired it up, and after the pyrometer worked its way up to 500 degrees, it fell to <100 and wouldn't move. I went ahead with the bisque, using the clock to achieve my tried and true firing schedule but turning it off manually a little sooner than it would normally turn itself off. The next day I found that the pyrometer probe had separated/broken where the two prongs come together. I took the small kiln and pyrometer to an electrical repair person who has been in business for 40 years and owns a kiln of his own. (To my knowledge the closest kiln repair person is 100 miles away) He reported that the small kiln "worked fine" for him, and that he had soldered the tip of the pyrometer, which he then "got up to 400 degrees". Back to the studio to fire the larger kiln with the repaired pyrometer probe. I started to insert a pyrometric cone into the cone holder when I noticed that the 06 cone from my last firing, still in the cone holder, had turned into a white, glassy blob! It took some effort to chip it off the holder, but I got most of it off and fired up the kiln. The pyrometer was dead as a doornail. I went ahead with the bisquing, with the 2 lower elements on low, then turned the top element to low. A couple of hours later when I turned one of the elements to medium, there was a "pffft" sound and sparks flew from the manual control box. I flipped the fuse to 'off' and said "#@!! -- enough already!"

Am I just having a run of bad luck or is all of this somehow related???

I haven't checked out the small kiln to see if it is, indeed "working fine", but I have ordered a new pyrometer. Meanwhile, does it sound like the control box on the larger kiln can be repaired by an electrical repairman? I'm not sure the old larger kiln (18x18 chamber) is worth the expense of taking it to a distant kiln repairman, given that I was trying to "make do" with it until I can afford a newish 7 cu ft or larger kiln. Or do I need to give up and replace the whole kit and kaboodle?? I'm utterly baffled and I don't know where to turn.

Any advice or diagnosis or.....?? appreciated! Jayne

#2 DAY

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Posted 09 December 2012 - 07:20 AM

Your "oldie" is no longer a "goodie". Sparks from the control box mean parts need to be replaced. Depending on the make, parts are most likely available. That is what is great about L&L kilns- they stock parts for every kiln they ever made.

#3 TJR

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Posted 09 December 2012 - 12:07 PM

I guess my obvious question would be;"Why do you need a pyrometer?"
If you are firing manual kilns with kiln sitters, the cone in the kiln sitter will shut off the kiln. The moving of the pyrometer back and forth between kilns is what has caused it to fail. Unless you are doing something highly techical like crystaline glazing, or large sculpture, you don't need the pyrometer. What you do need is a good electrician to rewire your controls on the kiln. Any electrician should be able to do this for you. It just costs money, but cheaper that buying an entirely new kiln.
TJR

#4 Mark C.

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Posted 09 December 2012 - 12:24 PM

A pyrometer usually has three components-the gauge-the wire(which goes from gauge to thermocouple -the thermocouple(which is incased in some porcelain spacers)this part goes into kiln and has some metal looking heavy wire wielded together at tip.
Your story is a bit hard to follow-but I think your thermocouple is toast you cannot solder the tip to save it-buy a new thermocouple and throw the old one away.
Now as to sparks from the control box-you now need an electrician to look at it and fix it-you will need more parts most likely.
Mark
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#5 Isculpt

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Posted 09 December 2012 - 08:48 PM

A pyrometer usually has three components-the gauge-the wire(which goes from gauge to thermocouple -the thermocouple(which is incased in some porcelain spacers)this part goes into kiln and has some metal looking heavy wire wielded together at tip.
Your story is a bit hard to follow-but I think your thermocouple is toast you cannot solder the tip to save it-buy a new thermocouple and throw the old one away.
Now as to sparks from the control box-you now need an electrician to look at it and fix it-you will need more parts most likely.
Mark


Thanks, Mark, TJR and Day.

TJR, the reason that I use the pyrometer is that a couple years ago the kiln sitter failed to turn the kiln off. It's very humid here, and I think moisture prevented the sensing rod from releasing the trigger. That overfiring debacle was before I had a sense of how long it took the kiln to reach temperature, and with hours left on the timer, the failure to turn itself off was memorable! All it takes to shake my confidence in a piece of equipment is one disaster, so now I try to keep the timer set closer to the expected time needed, and I rely on the pyrometer in addition to the kiln sitter.

Mark, I didn't realize that I couldn't solder the tip of the thermocouple. Good to know. It's also good to know that an electrician can fix the control box once he figure out what I need and I order the repair parts.

Day, this is a Skutt kiln; I hope they follow the same parts practice as L&L.

Sorry the sequence of events was hard to follow. I guess the thermocouple breaking, the unexpected glass-like blob where the cone had been, and the sparks shooting out of the control box (all within a week) were unrelated....very weird.

Thanks again. Now I know how to proceed, even if I don't know why it happened!!

#6 JBaymore

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Posted 09 December 2012 - 09:36 PM

I guess the thermocouple breaking, the unexpected glass-like blob where the cone had been, and the sparks shooting out of the control box (all within a week) were unrelated....


Don't bother to buy a lottery ticket this week. ;)src="http://ceramicartsda...ault/wink.gif">

best,

....................john
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#7 Isculpt

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Posted 09 December 2012 - 10:14 PM

I guess the thermocouple breaking, the unexpected glass-like blob where the cone had been, and the sparks shooting out of the control box (all within a week) were unrelated....


Don't bother to buy a lottery ticket this week. ;)src="http://ceramicartsda...ault/wink.gif">

best,

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


YA THINK? (On second thought, John, I think I'm overdue for some good luck here...!)

#8 Mark C.

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Posted 10 December 2012 - 01:52 AM

My advice (I own two skutts) is tune up the kiln setter (adjust as manual says) and test with a guide cone (thats a large cone on same level as setter is on in spy plug hole area so it can be seen) Have the control box fixed (skutt parts are easy to order from skutt) get a new thermocouple (these wear out over time and give bogus reading before they completely fail )
Then you will have the kiln tuned up and working like new again for many years.
hopefully your pyrometer gauge is a digital one not an analog oldie.

I think all the woes where just coincidence. Spend your loto ticket money on kiln parts(better spent)
Mark
Mark Cortright
www.liscomhillpottery.com

#9 DAY

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Posted 10 December 2012 - 07:16 AM

"TJR, the reason that I use the pyrometer is that a couple years ago the kiln sitter failed to turn the kiln off"


Sitter failure is RARE, but when it happens the result can be a disaster! I have an old kiln that I do not entirely trust, and that is why I use a cone pack in front of a peep hole.

#10 Isculpt

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Posted 10 December 2012 - 11:00 AM

My advice (I own two skutts) is tune up the kiln setter (adjust as manual says) and test with a guide cone (thats a large cone on same level as setter is on in spy plug hole area so it can be seen) Have the control box fixed (skutt parts are easy to order from skutt) get a new thermocouple (these wear out over time and give bogus reading before they completely fail )
Then you will have the kiln tuned up and working like new again for many years.
hopefully your pyrometer gauge is a digital one not an analog oldie.

I think all the woes where just coincidence. Spend your loto ticket money on kiln parts(better spent)
Mark


Thanks, Mark. I don't have a manual -- this is an ooooold kiln that was loaned to me 3 years ago for my first firing by a potter who simply moved away without asking for it back! But I went online and found instructions for tuning up the kiln setter, so I'll do that and test it. No, my pyrometer gauge isn't digital, but I'm looking at ordering one. Anybody have a favorite? I've scouted a number of ceramics supply websites and found the prices range from $75 to $350 for a whole new pyrometer and thermocouple.

#11 Mark C.

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Posted 11 December 2012 - 02:17 AM


My advice (I own two skutts) is tune up the kiln setter (adjust as manual says) and test with a guide cone (thats a large cone on same level as setter is on in spy plug hole area so it can be seen) Have the control box fixed (skutt parts are easy to order from skutt) get a new thermocouple (these wear out over time and give bogus reading before they completely fail )
Then you will have the kiln tuned up and working like new again for many years.
hopefully your pyrometer gauge is a digital one not an analog oldie.

I think all the woes where just coincidence. Spend your loto ticket money on kiln parts(better spent)
Mark


Thanks, Mark. I don't have a manual -- this is an ooooold kiln that was loaned to me 3 years ago for my first firing by a potter who simply moved away without asking for it back! But I went online and found instructions for tuning up the kiln setter, so I'll do that and test it. No, my pyrometer gauge isn't digital, but I'm looking at ordering one. Anybody have a favorite? I've scouted a number of ceramics supply websites and found the prices range from $75 to $350 for a whole new pyrometer and thermocouple.


If you fire under 2000 degrees there are some very low price digital units if you need over 2000 degrees I suggest a used fluke off e-bay- price range is 50-80$
There are a few posts already coving this in detail-the thermocouple is a separate purchase -you will also need the wire with a plug that fits your pyrometer gauge.
Mark
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#12 Isculpt

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Posted 11 December 2012 - 09:41 AM



My advice (I own two skutts) is tune up the kiln setter (adjust as manual says) and test with a guide cone (thats a large cone on same level as setter is on in spy plug hole area so it can be seen) Have the control box fixed (skutt parts are easy to order from skutt) get a new thermocouple (these wear out over time and give bogus reading before they completely fail )
Then you will have the kiln tuned up and working like new again for many years.
hopefully your pyrometer gauge is a digital one not an analog oldie.

I think all the woes where just coincidence. Spend your loto ticket money on kiln parts(better spent)
Mark


Thanks, Mark. I don't have a manual -- this is an ooooold kiln that was loaned to me 3 years ago for my first firing by a potter who simply moved away without asking for it back! But I went online and found instructions for tuning up the kiln setter, so I'll do that and test it. No, my pyrometer gauge isn't digital, but I'm looking at ordering one. Anybody have a favorite? I've scouted a number of ceramics supply websites and found the prices range from $75 to $350 for a whole new pyrometer and thermocouple.


If you fire under 2000 degrees there are some very low price digital units if you need over 2000 degrees I suggest a used fluke off e-bay- price range is 50-80$
There are a few posts already coving this in detail-the thermocouple is a separate purchase -you will also need the wire with a plug that fits your pyrometer gauge.
Mark


Hmmmm. Hadn't considered the wire as extra. Thanks alot. I'll go look for the forum discussions re pyrometers.

#13 TJR

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Posted 11 December 2012 - 10:01 AM


A pyrometer usually has three components-the gauge-the wire(which goes from gauge to thermocouple -the thermocouple(which is incased in some porcelain spacers)this part goes into kiln and has some metal looking heavy wire wielded together at tip.
Your story is a bit hard to follow-but I think your thermocouple is toast you cannot solder the tip to save it-buy a new thermocouple and throw the old one away.
Now as to sparks from the control box-you now need an electrician to look at it and fix it-you will need more parts most likely.
Mark


Thanks, Mark, TJR and Day.

TJR, the reason that I use the pyrometer is that a couple years ago the kiln sitter failed to turn the kiln off. It's very humid here, and I think moisture prevented the sensing rod from releasing the trigger. That overfiring debacle was before I had a sense of how long it took the kiln to reach temperature, and with hours left on the timer, the failure to turn itself off was memorable! All it takes to shake my confidence in a piece of equipment is one disaster, so now I try to keep the timer set closer to the expected time needed, and I rely on the pyrometer in addition to the kiln sitter.

Mark, I didn't realize that I couldn't solder the tip of the thermocouple. Good to know. It's also good to know that an electrician can fix the control box once he figure out what I need and I order the repair parts.

Day, this is a Skutt kiln; I hope they follow the same parts practice as L&L.

Sorry the sequence of events was hard to follow. I guess the thermocouple breaking, the unexpected glass-like blob where the cone had been, and the sparks shooting out of the control box (all within a week) were unrelated....very weird.

Thanks again. Now I know how to proceed, even if I don't know why it happened!!

Isculpt;
I am thinking that your kiln sitter is dirty. You mention a blob of glass sitting on it[which would have been the melted cone]. Those two metal "t" shaped pieces on the inside of the kiln are removeable. Either replace them-cheap, or get a pair of vice grips, a bench grinder, and GOGGLES. You can grind them off and stick them back in. There is a guide for the sitter prongs so you can adjust them. I also place mine cone on the ends of the prongs rather than close to the kiln wall, so you have a better chance of it melting easily. The pyrometer is not a bad idea, now that I think of it. But Mark is right-you can't solder it back together. Doesn't solder melt at 200F?
Ain't Ceramics grand? We have all been there, mate. This was just your week.:Dsrc="http://ceramicartsda...t/biggrin.gif">
Tom Roberts




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