offcntr | Speed run

When I finished loading my last glaze firing, I had so many pots left over, and still felt a little under-stocked for my upcoming show. Jon, another Club Mud potter, suggested I do another firing with a four-shelf footprint; he does it all the time when he hasn't got enough for a full load. I did some calculation, and decided I had enough work to make it go, so the day after our coast trip, I was back in the studio loading the kiln.

Loading goes much faster with only four shelves. I laid them right down the middle of the car, and could reach to set all the shelves from one side, likewise the pots (no more squeezing between the table and the door to get to the back side). With only two-thirds as many pots, the loading also went faster; I started around 8 am, was done by noon. Fit every one of my leftover pieces in, even dusted off a few demo vases from pre-pandemic Art and the Vineyard and glazed them up. Because I assumed the firing would also be faster, I started the pre-heat at 9 pm rather than my usual 8-8:30. As it turned out, I coulda waited until 10; cone 08 was down one the bottom the next morning at 5 am, cone 04 on top. I adjusted the gas and air from warm-up to full and slammed in the damper for a later body reduction, hoped for the best.

Firing day was much easier than usual, because I'd not done any glazing, so didn't have glaze room and floor cleaning. I did mix up a couple of batches of glaze, but most of that had already been done the previous week as well. So I spent much of my morning on the wheel, throwing incense dragons, getting a head start on my next production cycle.

The firing went smoothly, but fast. Cone 8 was down by 1 pm, cone 10 by 3. I soaked it an extra 15 minutes to help the bottom catch up, but shut everything down by 3:15. Shut off the burners, closed the ports, bled off the gas line and shut it down. Recorded the gas usage--55 units, about nine less than last fire.

Forgot to close the damper.

Which I only discovered the next morning, when I came down to box up my dragons to take home. The kiln was already down to under 700° F, way cooler than normal. I slammed the damper closed, praying that I hadn't broken all my pots by cooling too fast.

The suspense lasted until Sunday morning, because Saturday is Market day, and I'm far too tired afterward to even consider going down to the studio. We pulled open the kiln... and it was beautiful. Shiny, creamy pots, just enough iron speckle, lovely colors. Temperature difference between top and bottom less than half a cone. The usual amount of oxidation, but no over-reduction on the top.

The only breakage from the speed cooling was in a couple of Jon's pots, refires with glaze touch-ups. One was a mug he'd ground free of glaze drips, that ran again and stuck to the shelf, then cracked in cooling. The other a very thin bowl that just cracked from rim to base, either from speed cooling, or possibly heating--it was right at the top, which heats up fastest.

Jon says his pots are a little shinier than usual, probably from the cooling (crystal formation takes a slow cool-down). If that's the case, I may do a short speed cool after my next firing--but not all night--to see if it can help control the brown, matte surfaces I can get at the very top of the kiln.

In any case, here are pictures. And I finally feel like I've got proper back stock again.