Kiln not getting hot enough

[Katie S]

Hi everyone!

 

I recently purchased a used Olympic Kiln 1214-120T. It has a kiln sitter and I’ve familiarized myself with how to use the kiln, but I’m running my first cone 6 attempt and I don’t think it’s getting hot enough.  It’s been on high for about 6 hours and was slowly ramped up from low to medium over a four hour period. I have witness cones in the kiln and the middle cone isn’t bending yet. Any guesses?

[Katie S]

To add to this, the outside of my kiln indicates it gets up to cone 6, but it looks like more recent models only get to cone 4.  I’m wondering if my kiln will even get hot enough. 

[Bill Kielb]

Post a picture of the kiln tag but you are right in saying the newer models are only rated to cone 4 or perhaps derated a bit over the years to cone 4. For kilns that need to get to cone 6 repeatedly you will find folks buy a kiln rated to cone 10.

This may sound counter intuitive but really the maximum rating is a number something could get to at its very very best. When electric kilns fire the elements wear a little each time. So a reasonable rule of thumb is a cone 10 rated kiln will usually fire maybe 150 firings at cone 6 before it wears enough to require element replacement to make cone 6 in a reasonable timeframe (prox. 8-12 hours).  Clay and glazes depend on a maximum temperature but also a minimum speed of firing or heat work. Really not unlike baking so 350 degrees for 25 minutes to make a great pizza  would be considered appropriate but if it took hours just to reach 350 degrees our pizza would likely not be tasty in the end.

Post a picture of the kiln tag to confirm , but it likely is more suitable for low fire (cone 04) work or perhaps even built more for glass firing.

Edited June 29, 2023 by Bill Kielb

[Katie S]

That's really good to know, I had no idea!

I've been trying to post a photo and it won't let me - but I imagine that's exactly what the problem is.  Thanks so much for taking the time to respond!

[Pres]

@Katie S, Rating on the kiln from the manufacturer is Cone 4. Give away for me is the 120V  with the 20 amp breaker. I would say you should be looking at a cone 4 clay body, or even a little lower, as the is the max on the kiln. 

IMHO, of course, but the specs are there. Sorry to be a bearer of bad news, as it seemed you were looking for a ^6 glaze firing.

best,

Pres

[Mark C.]

23 hours ago, Katie S said:

That's really good to know, I had no idea!

I've been trying to post a photo and it won't let me - but I imagine that's exactly what the problem is.  Thanks so much for taking the time to respond!

Make the photo smaller pixel wise-read the header on posting photos-

Here

 

I run mine thru my mac I photo to meduim size mail them to myself and post from there-PC is another animal. They are to big most times so make them smaller

Edited July 1, 2023 by Mark C.

[Katie S]

On 6/29/2023 at 8:04 PM, Pres said:

@Katie S, Rating on the kiln from the manufacturer is Cone 4. Give away for me is the 120V  with the 20 amp breaker. I would say you should be looking at a cone 4 clay body, or even a little lower, as the is the max on the kiln. 

IMHO, of course, but the specs are there. Sorry to be a bearer of bad news, as it seemed you were looking for a ^6 glaze firing.

best,

Pres

I have an older version of this kiln from 1990 and the panel on the outside of the kiln says it's cone 6.  I actually emailed olympic and they said that they changed it to cone 4 since it was more reliable.  Makes sense!