Tuesday, October 22, 2013

These are all the pots you can fit in a 4 cu ft soda test kiln; but since it's all I have these days, it's better than none at all. I'm still finishing up the bisque I brought from North Carolina and it's going to take me a long time to get them all fired since I can only fire when I have 3 guaranteed, clear, no rain days. And here in Southern Oregon that pretty well limits me to the summer and early fall.
I finally got this little Olympic to fire evenly, but the firing was not without problems. I really babied this kiln throughout, which is why I didn't get anything else done yesterday. I'm still getting back burning on the pilot burner, but it didn't seem to be problematic with the firing.. It's been that way from day one, so I'll have to see if I can remove that burner and figure out what's going on.

The firing was going great. I was dead even on temperature, top and bottom, and started the first round of soda spraying when Cone 8 was around 2-3 o'clock. I did two rounds of spraying, and toward the end of 3rd round, the kiln just uttered a horrible, burping sound and shut off. The temperature dropped like a rock. It took me a few minutes to turn it back on, but by then it had dropped about 200 degrees! OK, a pain in the butt glitch, but I got it back on  up to temperature. Then I  decided to do a final, light spraying and the darned thing  repeated the burping scenario and turned off again. This time I just surrendered and closed it down. Cone 9 was down flat with 10 starting and I know my liner glazes are fine at cone 9.
One of the good things about these portable, single IFB lined kilns is that they cool fast - really fast!  I checked the kiln around 9am this morning and it was already down to a hair over 100 degrees. So I unloaded, taking photos of each layer. After getting this thing to fire evenly, I was definitely going to get a photo record before I shrouded it in it's bright blue tarp, and rolled it under the eaves till the next firing,

In the next couple of days I'll get those burners cleaned out and wire brush the horizontal bar and see if I can find what's causing the back burning on that pilot burner.I just hope I can get those burners off. I'll probably need to make a trip to Lowe's for spray to unlock them, since I don't think I have any on hand. 
I'm not sure why those burners shut off other than perhaps the soda caused some back pressure to blow out the pilot, but why didn't it do it the first two rounds of spraying which were as long as the third and  twice as long as the fourth???? It is a puzzlement. I'm just wondering if the regulator is going; but they usually last more than 3 firings! Next firing I may just depress the red button with a C or similar clamp before I start spraying, or just get Jim out there to depress it and be there as an extra set of hands in case it happens again.

The pots came out well, but not as reduced as much as I  expected, based on how early I started reducing and reduced till the end.  In fact, I was concerned that my oribe accent on one of the pots might go livery red, and was amazed to see a bright, beautiful oribe.  My blue green celadon liner was reduced enough to be pale green but not the deeper richer color it can be with a stronger reduction. The flashing slip wasn't as rich an orange that I can get with the addition of a bit of salt to the mix. It looked more like it would without the soda, but no real problem there.
All in all I'm happy and very relieved that the pots survived those two shutdowns. Only one of the small bowls had a tiny piece of kiln wash find it's way in the bottom. I'll need at least a week before I even consider another soda firing; and it may be longer since I don't think this lovely, sunny weather is going to last this time of year.
Meantime I need to get to the pottery supply for the few things I need to batch up my other liner and accents glazes. Other than that, the rest of today is going to be a day of rest and paperwork and make a clean chart of the firing that I can follow next time.

There's not much work to show for the time spent firing such a tiny kiln, but the win for me was getting this kiln to fire dead even, and of course, freeing some space on my ware cart in my current, limited, studio space helps as well.


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