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Duncan Kiln sitter LT3K not getting hot enough

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Hey so I'm some what new to kilns and repairs, I got this kiln from an estate sale it needed a few parts but it was fully functional so far I've successfuly completed 2 full firing cycles bisque and glaze to 1080°c I'm happy with the results. 

I've been planning some cool peices for Christmas presents and I need to fire ASAP but the last fire I did Was a fix up firing for peices that needed to go a bit hotter and the kiln sitter didn't turn off lucky I was there to shut it off, I checked it and the cone 04 hadn't melted, the wares were fine and seemed to have done ok; I hadn't been using witness cones. So yesterday I test fired it for about 2 hours going up to setting 8 which should be s somewhere in the 1200 -1500 range I believe and the sitter still didn't turn off at cone 04 and the cone didn't melt. And the witness cones didn't seem to melt either, so I don't know what's wrong with it I cant see any visable problems except maybe some of the outer metal needs tightening 

(I'm planning on buying a pyrometer and a kiln plug for the peephole, I think converting to digital is a bit hard and expensive) 

Is there an obvious problem? Any ideas how to fix, should I pay for a firing service for my Christmas items? I live quite close to some

Images on Google drive click link


Thanks for any help 



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Well, this is a fiber kiln that I believe we just concluded was rated cone six so as it ages it will not get to cone six. As it ages more it won’t get to cone 04 as well because the elements wear a bit each and every time it’s fired. So our conclusion was since replacing elements in a kiln like this appears to be nearly impossible it should likely have a life as a cone 04 kiln.

Now all of that is true, but really very few kilns produced ever will make it to cone 04 in two hours. Setting it at #8 on the dial only determines how much power is available and really establishes how fast it can fire. For a typical bisque firing for a functional kiln normally the power is turned up gradually so the firing makes cone 04 in about ten hours. Whether yours can achieve this is hard to say from your description of your past firings and your understanding of the dials on the kiln.

Most kilns need all their power to get things done so a typical bisque schedule would be a few hours on low, maybe two hours on medium and the remaining  hours on high. This often gets a nine to ten hour bisque done,

So do you have enough power, It’s hard to say until you turn it all the way on high. Will you have enough power to reach cone six? Maybe, but soon you likely will not because this kiln was really likely intended for lowfire clay work.

Edited by Bill Kielb
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How long are you letting it run? Is there a timer on the sitter, and is the timer shutting it off? You may simply need to turn it to high at some point, and you may just need more time on the timer. As Bill said, you should be firing it in a way that takes more like 8-10 hours to get the best results. Can you post a picture of the controls?

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Thanks guys so I'll do a 12 hour bisque firing and see if it makes it to 04,

So I was not giving it enough time to reach the cones  on the shorter firing 

For my bisque ans glaze firings I have been spending  at least 2 hours on low 2 on medium and the rest on high and that seems to have worked,

 I shall go back to that and see how it goes 

Thanks for help 

Edited by Rorybrittain
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If it doesn’t make it to 04  with the last few hours on  it’s highest setting in twelve hours, it will never make it to cone six in a glaze firing. Time for new elements. LT3K is the model number of the kiln sitter which is just a switch to turn the kiln off when it reaches the appropriate combination of temperature and time often referred to as heatwork. Your kiln  likely is made by Duncan . There should be an equipment tag on it with make, model, serial no. Voltage, wattage, etc.... that you can use to find  the literature on it.

Edited by Bill Kielb
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12 hours ago, Bill Kielb said:

Your kiln  likely is made by paragon .

I don't think Paragon made them, they just took over the servicing of them when Duncan stopped making them.

Paragon has very few parts left in inventory, so Euclids.com is probably the best bet for getting elements.

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