Sunday, March 3, 2013
Thanks again bloggers!
I spent some time this morning weaving, and that settled me down a bit, and gave me time to think this through, absorb all of your posts and then do some reading in my pottery problems bible. I love this book and can almost always find the answers to my questions here.
It seems hard to believe that I over fired, my pyrometer just barely hit 2205f and I shut down the kiln. I was freezing and ready for supper. Is 2205 too hot? Of course, there is no way to tell if the pyrometer was correct, although it is very reliable when I bisque and raku fire. It is a likely reason for the bubbles though, it happens to me when I raku too hot, but it also happens when I raku too fast.... It would have been most helpful to put in cone packs. I don't use them and the one time I tried to there was no way to see them, there are no spy holes you can view them through, and they matched my pyrometer, so I thought I was good to go. It would have been helpful to have put them in with this firing to see if I did indeed overfire, which is likely.
The other cause for all of this is likely, as you said, rapid firing. The kiln jumped up in temp a couple of times and I got impatient at the end and bumped it up a bit. I ramped up mostly at 270 per hour. Is that too fast? This is the schedule I have used in the past.....
I do know that it's not the clay/glaze fit, I have seen these two together and they are fine.
oh and ps: I was wrong in my comment about the one bowl that bloated, that's it in the top photo, beautiful bowl except for a tumor on the inside, it was the 266 clay, not the raku, and yes, that clay body is prone to bloating, again, maybe over fired. I knew going into this that 266 is a problematic clay, but it is a beautiful clay body, I love throwing it and I love the dark brown raw clay, I do not love the problems it brings with it though. Maybe I will hand build some dishes that aren't glazed with what I have left of it......
Oh well, whatever, I'm over it, ready to move on. I have some tiles I want to make for raku and I have little houses and pendants waiting to be raku fired. I had this thing about bowls that I needed to get out of my system and so I did. I have no desire to make any more right now, maybe later...... for now I will just enjoy all of the great ones I have from other potters.
One other question: would it be worth a refire, or more fun to smash them with a hammer? I could take care of that right now!
Thank you all once again, I truly value your input!!!!!! Wise words and much appreciated sympathy :)