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Wednesday, December 9, 2009

Unbelievable !!!

The only thing going thru my mind right this instant is: this is totally unbelievable !!!
Unaccountable, without rhyme nor reason, illogical, implausible, mind-boggling, unbelievable.

For 3 years, i've tried to get my gas kiln to reach temps even approximating 2167 °F. Have prayed, sworn a blue streak, researched extensively, and with a heck of a lot more patience than my personality type normally exhibits - tried, tried and tried again.

Finally, as most of y'all know, decided to modify all my glazes down to ^01 which this kiln will do with ease.

Overnight temps here in the valley reached a high of minus-12 degrees last night and by 6am twas only basically zero. In the attached garage, the temperature gauge read 15 degrees. Figured that was too cold for the electric kiln's digital-programmer to function.
Guessed that i could figure out how to run the gas kiln in straight oxidation.
Have never tried this before. Gas kilns are for reduction firing, right?

Oughta mention here, that i always stack a kiln immediately before using. Otherwise the glazed pots sit in the house where normal temps range at 68°. Carried them out to the garage, loaded the kiln (which was icy cold) and started the pilot. Normally, the kiln is run on pilot for 2-hours before turning the main burners up.
But this is very early am and i'm not quite awake. It occurs to me, that pots which are already 68° might not survive being rapidly cooled to 15° and then reheated.
There was also the kiln factor. Figured the pilot burner was not going to heat that kiln much above the garage temps.
Cranked on the main burner just as low as it would go and waited. Two hours later, it was holding at 1000°F. Pushed the main lever ¾'s open with the draft completely uncovered and all ports open. (Trying for oxidation.)
From past experience, was expecting that in about another 2 hours, temps would have reached around 1827° . Of course, in the past have gone for body reduction at ^012 or around 1550 - 1620°.

Ah but no, the Cosmic Joker was messing with my mind but once again !!!
The thermocouple in the top port read: 2400°F ! The middle port temps were: 2350°F

Just couldn't believe what my eyes plainly saw. Stood for several minutes switching the thermocouples from one port to another - top, bottom, middle. Letting the thermocouples reach room temp and reinserting them into the peephole ports.

Yep! They actually did read 2400°F at the top; 2350°F at the middle.
And climbing !!!

The glazes are going to be fried, of course. More pots to add to the reject pile which is growing well-nigh out of hand. And actually, until the kiln can be opened tomorrow - am not even sure the Cone 6 clay didn't melt to puddles in cone 10 temps !!!

Main question here is: is this a fluke? Somehow related to the zero temps outside? Or is this a repeatable operation?