Old Dawg, new trick!
I just unloaded my first firing of Sweet Baby Jane and I quickly got busy glazed up another load and she’s firing again tonight. I really hadn’t made pots for this kiln so I was thankful to have a couple of boxes full of slab trays that Andrew made for me during the summer. I couldn’t resist some temmoku- the glaze that potter’s love and never sells. I got carried away with a cobalt blue glaze Jane gave me. I was thinking of paying bills and remembered the motto- if it doesn’t sell reglaze it blue and if it still doesn’t sell salt fire it.
One of the many reasons I like the carbon trap glaze is that it does make the pot look wet again. Wet pots especially freshly slipped ones are my favourite time in a pots life. Because it looks wet it is hard to photograph so I just am showing some close ups. It is dark, I’m tired and I’ll be up till 3:30, teach tomorrow, meeting tomorrow night and then the gang arrives here for a 3 day marathon wood firing. No rest for the wicked!
So the new trick is how this kiln fires. The program Geil suggests for carbon trapping has the kiln go into light reduction around 1650F. It doesn’t go to the extremes of pushing the damper in and having smoke coming out every peep and around the door. Something I used to do. It moves slowly up to medium reduction and holding up to around 2200F. I was talking to Jane on the phone at about this time and she asked “ Has it dropped yet?” I didn’t quite get it, hung up and went out to check the kiln. There was a green flame out the stack, and both peeps. Good back pressure and the gas had been turned up and the damper opened. Oxyprobe reading neutral to really light reduction. What the Sam Hell? I had always fired all the way up to Cone 10 in reduction with the damper a whole lot further in. Who am I to argue with a computer that is likely smarter than me. Well the computer wins. The glaze is a nice smokey shino wth little mouse gray spots of carbon trapping. This firing I still have the blues I've just tuned them down.
When we got our Geil kiln at school back in 2009 I started firing like we were taught in school, heavy smoke and flame coming out of every oriffice. I soon learned after getting an oxy-probe through a grant, that I could get quite good reduction with no smoke or flames coming out of the stack, just good back pressure at the spy holes. I then set the primary air disks on the burners open just to the with of two stacked popsicle sticks, drew lines every 1/8" on the damper and used 1/2 the gas pressure recommended by Geil. After getting to the top gas pressure I would use during the firing, the only adjustment I made was moving the damper in, then back out 1/4"! Damn fine kiln!
..... And the good don't need it Good firing Señor