Sunday, March 28, 2010


Sorry for the delay getting these pictures up. Over all we had a good firing. As always there are things to improve. First thing to improve is probably our clay body. We keep getting small cracks on our pots in the front of the kiln, and this firing a couple of the larger platters slumped slightly. Not much but enough that what used to be a nice platter now looks like it was poorly made. Our clay is a mix of kaolin, and ball clay with about 8% neph sy, silica, and grog. We were aiming for a clay that flashed well.

Faceted box from this last firing.

I am pleased with the way our clay body flashes. However the cracking, and slumping aren't so pleasant. Mind you we didn't lose that many pots from this last firing due to clay issues. Still room for improvement though. We'll probably start by taking out 10-20% of the ball clay and substituting some Hawthorne bond clay (fireclay) hopefully we won't lose too much of the flashing we like so much.

Our new glazes were a bit of a mixed bag as well. The whites came out fairly well. In the front of the kiln they got hot enough to become a little more glossy than they were in our test kiln:

Still pretty nice though.

In other parts of the kiln they were much closer to what we were expecting in from the our testing in the small gas kiln.

The green ash glaze was pretty good, though it did run more than we expected, and pooled blue in the center of a few bowls:

This one is a nice example. However in some cases the blue completely masked a decoration I had inscribed in the dish. All in all though I think this glaze is a keeper, we'll just have to use it a little thinner than we did this time, and be aware of it's tendency to run.

The black glaze on the other hand
not so black. It also turned green where it got hot. We don't hate it, but we'll probably keep working on this glaze to see if we can't come up with something better.
That pretty well covers it for news from our last firing. A couple more pots from this last firing:

Christy's been working on different handles for her boxes:

Another nice example of our white glaze:

A large unglazed jar from the front of the kiln. You can see a color change right where the two pieces of the pot were put together. Not sure why...same clay...
not bad though.

Thanks to everyone for encouraging me to try out curved teapot spouts, they are really starting to grow on me.


Linda Starr said...

Great firing, I really like the white pieces, especially the big white platter, and the first faceted box. Strange about the two colors on the unglazed jar, wonder if that could be due to smoothing the surface differently after it was just made?

Ron said...

Hey, Pots look great. I am a fan of the curved teapot spout, esp on those nice forms w. the over head handles.
Why the N.S. in the body as opposed to Custer Feldspar or G-200? I guess I'm thinking the NS is more of a lower range flux. ?? Maybe has something to do w. the slumping. But those big pots seem to be holding up well. I don't know just thinking out loud. Nice color on that first piece esp.

Joe and Christy said...

I have to admit my knowledge of clay bodies is somewhat limited. We did do some testing though. We really liked the sheen we got when we substituted neph sy in for G-200. We don't salt our kiln at all but we enjoy that little bit of self glazing that we can get from the addition of neph sy. I'm sure you are right though and if the fireclay doesn't fix the problem we probably will remove the neph sy. Really we just need to sit down and do some more comprehensive testing to figure it all out. We've done a lot of glaze testing, it's fun and easy to do in our little kiln. Obviously we don't have it all figured out but we at least have some idea how different ingredients will effect the glaze. With clays it's a little harder to test as our little test kiln doesn't provide any real information on how clays will react to the wood firing. So we're still kind of stumbling around with clay body formulation. One of these days will put the work in to start figuring it all out.....

deanandmartinpottery said...

You both had a good firing. We know you all are tired of seeing snow this year. Spring is on the way. The work looks great hope you all are doing well. I noticed that you said that you had some cracking problems in the front of the kiln this time. Are the cracks running vertical from the lip or the foot or are they horizontal and if they are do they go completely thru the wall or are they just in the surface. Is the glaze around the crack rolled back or is the sharp to the touch. Just wondering these things are always tricky but I know you will work it out soon.