January 2020 Soda Firing

After my first firing at NCC, I was totally excited and ready to go on another soda firing. I was worried about the length of the firing as the last firing was 16.5 hours and with this one, I was hoping to down-fire for a longer period of time and to a lower temperature. Luckily my friend and colleague, Joel Edinger-Willson was interested in teaming up on a firing. We planned that I would do the late-night turn ups, Joel would start the active firing, we would overlap during the day, and I would finish up the firing and down-firing. This was great! It allowed for us to both cut down on active firing hours and not be as sleepy.

Materials:

• My Porcelaneous Stoneware and Continental Clay’s Woodfire Porcelain with 12 mesh brick grog wedged in.

• RF East Soda Flashing Slip from UWRF.

• RF Blue Celadon from UWRF.

• Basic salt/soda wadding and Newman Fireclay wadding.

Notes from the firing up in temperature:

• The kiln had about 15 hours to preheat before the active firing time.

• When Joel came in in the morning to turn the kiln up, it was at ^1.

  • This is beyond my normal reduction cycle of ^011 - ^1

  • Because my midnight turn up was a bit robust.

• At hour 6.75, 7.25, and 9.5, I sprayed 375 grams of soda ash mixed with one gallon of water into the kiln.

• Was kept in a reducing atmosphere for the next hour until the cooling cycle began.

• Overall took about 10.75 hours.

Results / Post Unloading Notes:

• There was a great dispersal of atmosphere and soda ash from top to bottom. I would attribute this to the way that I loaded the kiln to promote more atmosphere to reach the top of the kiln.

• There was some good directionality and flame trails.

• Some halos appeared around the Newman Fireclay wadding.

• There was also lots of reds. I think this is from the reoxidation cycles during the down firing.

• Looking back, the down-firing was more oxidized that I would have hoped. As a result a lot of carbon trapping was lost and some of the matte surfaces and variety of color that I saw in my last firing was also lost.

• The longer spraying cycle also seemed to spread the soda ash out more and possibly leave less intense variety around each vessel.

Next Time:

• Shorter spraying intervals with more reduction between spraying.

• Spray when ^9 is bending or down.

• More reduction during the down-firing.

Summary:

This firing was not what I was hoping for, but I still did learn a lot from it. Skipping my normal reduction cycle at ^011 - ^1 was very informative. This is something that I have thought about trying for a while but was always worried the colors would not be as rich. I was wrong, the colors came out great regardless and I now know that I can pass through this during the overnight preheat leading up to the active firing time. This will allow me to reach hotter temperatures with less effort and give me more energy to focus on the end of the firing and more importantly, the down-firing. As a result of the firing being oxidized through the down-firing of this kiln, I am not very happy with the surfaces, but know what to not do next time; oxidize the kiln during the down fire.