The temp. climb was steady and I felt good about the whole firing until around 3:30 pm. Cone 8 started bending on the bottom shelf and nada on the top shelf. For the next hour I watched as cone 9 went down on the bottom shelf and....nada on the top shelf- not even 8. At 5pm cone 10 started bending on the bottom shelf and....nada on the top shelf. Grrr. what to do? I waited another half hour and shut the kiln down. Lack of heat balance led to lack of mental balance and I checked out, fearful of overfiring the bottom and deluded myself into thinking the top would be ok.
Well, it isn't :(
I opened her up and...................dull, dull, dull.
The cones on the top shelf barely moved and the bottom shelf showed a perfect cone 10. I think those top cones were giving me the finger!
|Top Peep Hole|
Cue the pouting.
Lucille lacks balance...boo.
Early in the firing I looked into the burner port holes and it seems the target brick on the left is too narrow, allowing too much flame through. That could account for more heat on the bottom. While loading the kiln I moved the target bricks closer to the back, hoping it would drive more heat up because the second firing also lacked balance and over-fired on the bottom shelf. But it looks like that did not make a difference; maybe I need to move it even closer.
I re-read my manual. Yes, move the target brick closer and yes make it wider to keep the flame from going right into the door. I also read that if there is a large heat split between top and bottom it's best to just shut the kiln down because you will never get it to even out- that something needs to be adjusted.
I plan to re-fire the kiln on Saturday and am committed to staying on target to see it through ~ no matter how long it takes.
Thanks in advance for any input you may have~