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TonyC

L&L CNOS Adjustment Needed? Help

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I have the following:

2007 L&L e23S-3 kiln with Dynatrol 700.   Changed elements and thermocouples ~1.5 yrs ago, but only ran kiln 6 times since then (moved and had to rewire new house).

Recently slow bisque fired to Cone 06.   CNOS was adjusted to 9020 due to previous "hotter" firings (based on previouys actual cones).   I checked cones after this firing and the Cone 05 had bent some (see pic - Cone 05 left, Cone 06 right), and the Cone 06 was completely bent over.

Per the system, final temperature reached was 1804 F (with 20 degree offset = 1824 F).   Per the Orton information, the Cone 05 at the 1 3/4" height is equivalent to 'self supporting' data or 1888 F (cone 06 = 1828 at this height).    

QUESTION:   Is it okay for the kiln to demonstrate this kind of offset between thermocouple readings and actual?    I don't know how to interpret the latest Cone 05 bend, and how to correct the system for it.   Should I be offsetting 30 degrees or more?   BTW:  I had checked the kiln after reassembling it in the new house, and I know the thermocouples were pushed to the end of the ceramic tube.

I will welcome any help or additional questions.  Thank you.

Tony

 

2019-01-05 Cone Bisque Firing.jpg

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I'm not getting how those cones were placed in the kiln. Are those small or large cones and were they in a cone plaque?

edit: page 8, how to make a cone pack. 

Edited by Min
added link

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Yeah that's interesting, but using the cones like that won't give you an accurate reading, they need to be vertical at the angle indicated by the bottom, gravity has too much say when they're placed horizontally and it would be hard to tell when they've tipped

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25 minutes ago, liambesaw said:

Yeah that's interesting, but using the cones like that won't give you an accurate reading, they need to be vertical at the angle indicated by the bottom, gravity has too much say when they're placed horizontally and it would be hard to tell when they've tipped

Oh.   I have only put the cones in this way.  Ughh.   I put them in exactly as the picture shows.   All are basically at 3 o' clock (side view) going into the kiln.   I thought this would be okay.   "Min" above has added a link for a proper cone pack.    I better do it that way next time.    

 

For now, should I not trust that the kiln is 'too' hot?    I guess I won't know until next firing.

 

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3 minutes ago, TonyC said:

Oh.   I have only put the cones in this way.  Ughh.   I put them in exactly as the picture shows.   All are basically at 3 o' clock (side view) going into the kiln.   I thought this would be okay.   "Min" above has added a link for a proper cone pack.    I better do it that way next time.    

 

For now, should I not trust that the kiln is 'too' hot?    I guess I won't know until next firing.

 

Correct. You need to fire again with the cones set properly.

It doesn't matter what the temperature readout on the controller is. It only matters that you're getting the correct results. If that means cone 05 is bent perfectly but the readout is 20 degrees off from the Orton chart, that's fine.

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35 minutes ago, Min said:

I'm not getting how those cones were placed in the kiln. Are those small or large cones and were they in a cone plaque?

edit: page 8, how to make a cone pack. 

Min, it looks like I completely messed this up.   The cones were simply layed out sideways as in the photos (with the exception of the bending).    Someone told me this would be okay, but it appears not.   I reviewed your link, and will be sure to do it this way next time.   I am so glad that I asked.   Thank you for the feedback.   

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2 minutes ago, neilestrick said:

Correct. You need to fire again with the cones set properly.

It doesn't matter what the temperature readout on the controller is. It only matters that you're getting the correct results. If that means cone 05 is bent perfectly but the readout is 20 degrees off from the Orton chart, that's fine.

Thanks for the feedback.   My next firing should be glazing, but now I'm concerned that the kiln may not be best calibrated.   I wonder if I should consider bisque firing again.   I have less to lose that way.

 

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You have to remember that TC offsets affect every temp, but cone offsets affect only that cone. I would put everything back at factory defaults and do test firings with cones at both bisque and glaze (assuming they're different cones), and then determine which adjustment should be made.

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1 hour ago, neilestrick said:

You have to remember that TC offsets affect every temp, but cone offsets affect only that cone. I would put everything back at factory defaults and do test firings with cones at both bisque and glaze (assuming they're different cones), and then determine which adjustment should be made.

Just to add , test firing an empty kiln is ok, but you will need to test fire under loaded condition as well. Self supporting cones make this easier to do as it ensures they are initially set at the correct angle. Cones are made of glaze about six cones less than their firing temperature so as they soften gravity pulls them down.

as Neil said  desired results are most important, so as long as you are not significantly under or overfiring most folks put the greatest importance on experience and  the intended result for their glaze / work product.

Edited by Bill Kielb

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