Thursday, February 24, 2011

Firing Today in Car Kiln

After struggling with the flu/cold for the last week, I was finally able to fire the large gas kiln today. It was actually the first day that I have had enough energy to do this firing, although the pots have been ready for a week. The photo below is of two large covered jars, which if all goes well, will be a beautiful copper red. So much can go wrong with these and I am a bit apprehensive, though it appears that things went well.

Above this saggar, are several shelves of dinner plates and bowls, and a couple of horse sculptures by my friend Bill Schaaf. There are also some oilspot bowls hiding here and there.

I must say that when I tried to push the car in, things were a little cramped and minor surgery had to be performed to get the car to settle correctly, well not quite correctly, but close. There was about a quarter inch at the bottom where the car did not touch and I did not notice it until the kiln was already hot.


John Bauman said...

Nice visual. I was just talking with another potter about saggaring copper glazes. Do you do it to keep the copper around the piece, or to control the atmosphere? (or neither?)

John Tilton said...

I don't know. It just seems to work for me and the way I fire. At one time I got some Empire splits and painted them with copper red glaze on one side, and that did not seem to do anything. But I still use the splits; in fact you see every single one I have left in that photo.

I know a lot of people just fire them as they fire and those copper reds are nice too, but I get flashing if I don't saggar.

sheapottery said...

I'm wondering how your oilspots come out if you're firing in reduction. Do you get any spotting? My understanding is that to get the spotting you should fire it in oxidation. Do you get copper flashing from firing them in the saggar with the copper reds?

Any possibility of posting a pic after the firing?

John Bauman said...

Now I'm even more intrigued. I semi-saggar my copper green (build a wall of soft brick around the piece) so that it will stay green. If I don't -- especially in areas of the kiln with lots of draft, the copper gets spent and the glaze goes white.

When I noticed that, I started firing copper red shard pins in the shadow of my copper green pieces. Sure enough, the copper red became never-fail due to the copper migration from the green pieces.

Furthermore, any clear/transparent glaze I fired next to my green glaze acquires a pink blush.

John Tilton said...

Jim, well you are right, at least mostly right. It's true that the oilspot mechanism happens in oxidation, but I have read that some of the best ones may not have been fired in total oxidaton. However in my case, these are refires.

I have a tendency to take something that does not look good and try something, anything, to try to help it. That is the case here. Might get a good one though.

Kevin Carter said...

Nice looking glaze, John!
What do you put on top of your sagggar? an old shelf?

John Tilton said...

I just go up with regular shelves. It might look like it's really unstable, but my post configuration is under the bricks so it was easy to just continue as if there were no saggar.