Tuesday, June 9, 2009
More cone 6 Reduction
I finished up my second cone 6 reduction firing this afternoon. For the non-potters out there, the above picture is of the cones at the end of the firing. The cones measure temperature and are the indicators we use to fire the kiln.
The firing took slightly longer than I had expected. The plan was to fire a little faster. I'm still troubled by how to keep the kiln climbing while gradually backing off on the reduction. I have forced air burners which I can control two different ways. Add to that the gas and the damper and I have too many variables to screw with.
I was reading Val Cushing's notes in which he describes how he prefers to fire using only the damper. He doesn't change the gas or air settings past going into body reduction. I might try that next time since I'm having trouble keeping the kiln climbing at more than 100-120 F per hour post-body reduction. I'm afraid I'm clearing the atmosphere more than I want to just to get the temperature up.
I'm also going to take some measurements of my chimney opening. I have a suspicion that Ian Craven may have made the opening smaller by adding a couple of bricks. When I follow Bailey's instructions my air flow does not seem to be adequate. The top gets around 200-300 F hotter than the bottom until I put it in body reduction. Then it pretty much evens out.
I guess there is a lot to learn, but I'm not going to dwell on all the numbers too much. The Studio Tour is in a few days so there is plenty of other work to do around here. The kids are out of school and there are playgrounds to visit and rocks to turn over. I was up at 4:15 this morning and there is a sack to hit.
This is the only picture I have of this basket. I had some customers stop by yesterday who saw this one and bought it. I only had it out of the kiln the previous evening and wasn't ready to say goodbye. Does anyone else do that: visit with the pots before selling them?