Sunday, March 23, 2014

Waiting is killing me, but I need the rest

Peeking in the kiln is addictive
I'm sitting here, and I've been sitting here off and on all day, exhausted after firing my wood kiln for 15 hours yesterday. I've peeked inside and I see a lot of potential for nice pots, but I see some potential for not-so-nice pots. It's kind of difficult to tell when peering into an 800-degree F. kiln. I've got a lot of local clay in this kiln load: some high iron clay from my land that I love to throw because it stands up so well on the wheel and still can be swelled out with ease; some clay from my land that comes out of the ground grey with streaks of iron through it and behaves a bit thixotropically (becomes less stable the more you work with it); some yellow clay from my land that behaves terribly when trying to form a pot on the wheel; some local clay from Cameron, NC that threw beautifully once I got some of the sand and grit out of it; and a couple of processed local clay bodies from STARworks Ceramics, one of which can develop pockets of gas that expand and develop bloating if fired to too high in temperature in my wood kiln.

My kiln fires unevenly, so I loaded the kiln such that the clays that don't like as much heat are in the back of the kiln and the clays that can take the heat are in the front of the kiln. Basically, the high-iron clays don't like as much heat, so they are in the back of the kiln, but a few made it toward the front of the kiln as well. The middle of the kiln is mostly a clay from STARworks called Okeeweemee 10 which is a dark clay body which has bloated in the front of my kiln before but seems to take more heat than my local high-iron clay. But there are a couple of pieces in the front of the kiln made from Okeeweemee 10. I think some of us potters like to take chances.

My wood kiln is designed to produce a lot of melted ash and flashing effects on the pots. Flashing is when you get subtle colors of sheen that develop on the outside of the pot. The way you load a kiln affects the way it fires, and with a wood kiln, it affects where the ash deposits occur and the flashing. It's one of the main challenges in loading a wood kiln such as the one I fire. I decorate some of my pots with trees, vines, etc. so I have to think about these things.

I put a small cup made from some of my high-iron yellow local clay right up front in the kiln when loading it, where it would likely get blasted by flame and ash. You can see it to the right of the tall vase at the left. It might have bloated, but it appears okay. I'll be checking it out tomorrow some time.

Tuesday, March 11, 2014

Iron-rich Clay and Trees for Wood Kiln

I've been busy with trees lately - incising them into a variety of my indigenous iron-rich clay, through a fine layer of white clay. I'll be firing them in my wood-fired kiln next week. This iron-rich clay is dug locally, some of which is from my own property. I've got one batch of some of my own clay from a new source on my property and I'm excited to see what it looks like when fired. I'll be firing this load of pots to a lower temperature and doing a slow reduction cool at the end of the firing, something I haven't done with the iron-rich clays. So, I'm excited about that as well, although there's always a bit of anxiety included when doing something ew. These tree designs - especially the more intricate designs - take a lot of time to create. When you subject them to a kiln atmosphere which can produce heavy ash deposits, you've got to arrange them in the kiln such that the designs stay away from the heavy ash. Otherwise, you'll end up obliterating all that intricacy. Here's a few pots I'll be strategically placing in the kiln next week:
Large covered jar
Medium-sized soul pot
Another soul pot with triskele design
Some teapots
Dinner-sized plates
Some pitchers
Upside down vases
Incising with a dull needle tool