Will my kiln reach temp?

[CabinClay]

Hello all and thanks in advance for any help!

I'm currently bisque firing to cone 04. I have an older, small Olympic kiln with a kiln sitter. Single control with low, medium and high settings.

I switched things to high over 6 hours ago, after running 4 hours on low and 4 on medium. Usually it reaches cone 04 after less than 2 hours on high. 

At what point do I give up and accept that this firing won't complete? I keep thinking that maybe it will reach temp if I give it a bit more time.....only to find that the sitter still hasn't fallen. 

Unfortunately I don't have witness cones for my bisque firings, nor do I have a pyrometer that reads at a high enough temp. Both if which I now realize I should have. I'm still relatively new to all this, so it's all a learning curve. 

Should I shut things off and give up for this firing? Or is it possible I might still teach cone 04?

Once the kiln has cooled I plan on checking elements and all connections. Just wondering what I should do in the meantime. 

Thanks for the help!

Mandy 

[Bill Kielb]

Your are at three times the length of time, If it does not complete, it’s only bisque, they can be refired.. Crazy idea but if you have a pyrometer you could see if it’s climbing at a slow rate. I assume you do not have one so for me personally, I would switch it off and repair it.

Edited July 26, 2022 by Bill Kielb

[Mark C.]

No and cones no pyrometer is firing blind. You can tell by color if you are trained in looking in on that . I'm with Bill turn it off repair and get cones and a pyrometer . You would never drive a car blind right gas cost to much and what else may happen?

[CabinClay]

Thanks for the advice!

I did end up turning it off, realizing it wasn't worth the potential lost work. 

I ended up pushing down on the kiln sitter a bit to help make it drop, which it did with limited extra weight. I wasn't able to do that earlier when I checked. I'm wondering if that means I was close to the temperature range of the cone in the sitter?  I actually had a cone 03 in the sitter, because my kiln fires cold with regards to the sitter (I fire to cone 7 in the sitter, in order to get a cone 6 witness cone to bend properly). 

Is it worth test glazing and firing a few pieces to see if they were bisque fired to a hot enough temp?

For reference, I used to bisque to a cone 06 (in my sitter), until I was advised to bisque to a cone 04. I also realized my kiln fires cool, and so now have a cone 03 in my sitter currently. When bisque firing to cone 06, I wasn't having any major glaze issues. 

Thanks again for help! 

Mandy

[CabinClay]

I should add that I would of course figure out the problem and fix it first! I'm just wondering if it's worth doing a test before re-bisque firing everything.

Thanks!

[Mark C.]

I suggest resetting your cone sitter with a guide to get that right-especially as this is your only point to tell whats going on temp wise.To tune it you will need a few guide cones as well to see if its working well. Neil posted a link recently on sitter issues.

Pretty good chance the ware will not need rebisqueing if they got hot enough-you can tell by the ring

[Bill Kielb]

8 hours ago, CabinClay said:

I should add that I would of course figure out the problem and fix it first! I'm just wondering if it's worth doing a test before re-bisque firing everything.

My opinion, timer to go through and make sure your elements are all good, or they have not worn more than 10% by measuring their resistance. After which if all good calibrate you’re sitter so you have something consistent to work with. Then re- bisque or just glaze firing is up to you based on the importance of the piece and whether you bisqued some test tiles in this run.

[CabinClay]

Upon inspection this morning I found that the failure was caused by a melted connection between the top element and the electrical wire coming in. This caused 2 elements not to work, as they run in series. My kiln only has 4 elements, so losing half probably means I didn't come as close to my goal temp as I hoped. 

I plan on re-bisque firing everything to be safe. Though I do have test tiles that I could run some tests on. Do you think it's worth it? Considering I had lost half my elements? I'm a little hazy about how this whole "heat work" thing might calculate into the fact that my bisque fire ran for so long. The cone in the sitter was not bent like I hoped. Thoughts on maybe just re-firing to a cone 06? To avoid things possibly ending up overfired?

Thanks again for the help!

[CabinClay]

I'm also looking into getting a pyrometer and was wondering if you would advice for or against any? They seem to vary quite a bit in price, from $50 to almost $200. I'd prefer not to spend a fortune, as the costs these days seem to be piling up.

Can I get away with a cheaper digital thermometer as long as I'm using a decent high temp probe? 

Thanks!

[Mark C.]

A cheap digital pyrometer is all you need-60$-the pyrometer probe needs to be better quaility-drill and install it in side of kiln in middle

If you need new elements get all of them not just 1/2 of them-you will need to ohm test them 1st

rebisquing will not hurt the pots

[Bill Kielb]

1 hour ago, CabinClay said:

The cone in the sitter was not bent like I hoped. Thoughts on maybe just re-firing to a cone 06? To avoid things possibly ending up overfired?

Re bisque them

1 hour ago, CabinClay said:

Can I get away with a cheaper digital thermometer as long as I'm using a decent high temp probe? 

 

Cheap is fine, use a regular high temp kiln thermocouple though.

I would also suggest measuring your elements and recording where they are from a wear standpoint.

[CabinClay]

Will do. Thanks again Bill!