Sunday, June 26, 2011

Firing Down in Electric Kiln

While my wood-fired pots have been getting most of the attention on this blog lately, I still fire the electric kiln quite regularly. I unloaded a kiln full of cone 6 pots glazed with a seafoam green glaze that I got from Richard Zakin's book Electric Kiln Ceramics. I think it's called K151 in the book.

A few years ago, I programmed the kiln to "fire down," that is, I slowed the cooling of the kiln from 1900 degrees F. to 1400 degrees. This promotes tiny crystal growth in the glaze and produces a much richer surface on some glazes. It worked a charm on Zakin's glaze, and I love the results.

When I unloaded the electric kiln yesterday, I was surprised to see that the glaze had turned darker than usual, a result of using a different clay body and having the glaze mixed a little thicker than usual I think. The clay is Little Loafer's Glory from Highwater Clay.

This piece blew me away, as I was worried that
the carving might have been obliterated.

Tree Stamp

Tree Stamp

One curvy line

Saturday, June 25, 2011

New Pictures of Latest Work

Here's some latest pots from our Manabigama Wood-fired kiln at From the Ground Up:

Click on an image and a "Light Box" slideshow should start. Then click on "next" at the right side of picture. Or just scroll down and click on pictures, then click outside the picture to come back to my post.

Summer Solstice Colors Clay

Levi and I unloaded the front of the kiln yesterday afternoon, but left the larger pots inside to cool until today. We're delighted with the results - lovely streaks of fuzzy green ash and brilliant soft orange mixed with copper.

Levi fired this kiln load, and I assisted. A tightly packed front and a loosely packed middle and back - in my opinion - caused the kiln to climb quickly once we began to stoke in earnest and climb above 2,000 degrees F. We shut the kiln down about two hours earlier than we usually do, but we managed to get close to cone 10 in the back of the kiln.

Ash buildup was minimal in much of the kiln. Flashing - where the flame actually creates color changes in the clay surface - seemed to dominate this firing.

I'll post more pictures later, but here's three of Levi's tall pots:

It was difficult not to pull these out
yesterday, but we felt they were too
hot to pull out until today.

The tallest of the three is 31 inches

Back side of pots.

The glass we placed on the large pot
melted onto the floor, so we'll have to
use a diamond blade to cut through
the glass to release it.

Thursday, June 23, 2011

First Peek

This piece is in the very back of the kiln.
I shoved a few pine sticks next to it
through the passive dampers in the chimney,
likely enhancing the flashing on the white slip.

This little vase thrown with fresh clay from our property
was pulled out of the kiln at around cone 10.

Wednesday, June 22, 2011

Summer Solstice a Hot Day for Firing

We blew a bit of extra ash into the kiln during this firing.

My daughter holds a board in front of the stoke hole
with a bit of ash deposited on the end, and I use an extractor
fan for an electric kiln to blow the ash into the kiln.

Thanks to Levi's midnight to 5 a.m. shift, we were able to finish up the firing today by 8 p.m., a 20-hour firing. We had three large pots fired green, so we took everything real slow.

WARNING: The following might be too much information if you're mostly interested in pottery and not pottery making.

We had thought we would be firing until after 10 p.m., but the kiln's temperature shot up quickly at the end, giving us a little scare at first.

We watched cone 10 drop in the front of the kiln, and an hour later cones 13 and 14 dropped. It usually takes about three or four hours to get cone 13 down after cone 9 begins to bend. I added cone 14 this time, thinking it wouldn't bend, so I was surprised when I noticed it was all the way down.

Cones (called pyrometric cones) are one of the most accurate ways of measuring temperature and heat work in a kiln. You place them in a kiln so you can see them during the firing and gauge your firing time. Cone 10 is about 2,340 degrees F. And cone 14 is about 2,530.

After we noticed all our cones in the front of the kiln had dropped, we fretted a while about the possibility of overfiring. Certain clays are designed to be fired to specific temperatures, and some of the clay we use undergoes a lot of stress at these high temperatures.

In the end, we decided to stoke until cone 9 was down in the back of the kiln (naturally a cooler area of the kiln because it's furthest away from the firebox). Once again, we essentially ignored the temperature in the front of the kiln to get the back up to a decent enough temperature. One of the reasons, we kept going was that we realized that the kiln didn't actually feel as hot as we normally get when at the end of the firing. I wonder about the accuracy of cones sometimes when firing in a wood kiln. All that ash melting on the cones...

We had some bloating (probably caused by overfiring) in one of the clays we used during the previous firing, so we were a bit worried about getting things too hot this time. We got cone 10 down in the back last time (our highest temperature yet in that section of the kiln). So, this time we shut the kiln down when we saw cone 9 down.

Everything looked good during my last peek into the kiln before sealing it up and going upstairs for some dinner.

Monday, June 20, 2011

Firing Levi's Big Pots in this Load

We're anticipating some interesting results in our next firing. We loaded three large pots that Levi created. They take up a huge chunk of kiln space, but we managed to get quite a few other pots in the kiln as well.

We'll be preheating the kiln with a gas burner tomorrow afternoon (maintaining a low temperature) and firing with wood beginning around midnight. Levi wants keep the kiln rising in temperature about 50 degrees an hour for the first nine or so hours.

Soul pots rest on top of Levi's special order
rain barrels in the back of the kiln.

The large vase wasn't easy to load.

We placed a planter on top of the large
vase and some small mugs on top of that
There's actually a pot inside each of the large
pieces as well, and a bit of sawdust in one as well.

Our only set of shelves is in the front

For more detailed photos of loading the big vase, click here.

Saturday, June 18, 2011

Customer Appreciation

Emma and Kate, sisters who live in New Salem, NC,
pose for a picture while Dad looks in through the doorway.
I was glazing some small mugs for the wood kiln, and I
decided to let the two girls decorate a mug with their finger.
Kate Rose made the mug on the left, and Emma Grace
made the mug on the right. Hopefully, the mugs will
survive the firing and the girls will be back for them.
As it turned out, Emma is left-handed and Kate is right-
handed, and the decorations were done on the correct
side of the mug so they could see the finger swipe while
holding the mug.

Friday, June 17, 2011

Prospecting for Clay

Chunks of raw clay drying in the sun

I've been walking regularly for a while now - using a trail I created off an old road bed in the back of our property. The old road bed crosses a creek, which is now dry, and I always look at the clay showing through the ground where four wheelers have gouged a trail.

Today, Levi and I dug up some of the clay and brought it back to give it a try on the wheel and in our kilns. We both grabbed a handful of some of the softer clay and wet it down and smacked it together a few times, then threw a piece on the wheel. I think it shows some promise. It's very similar to what I've dug up on another part of the property, but it seems to have some bluish clay in it as well.

We're both hoping that if we keep digging, we'll hit a vein of blue clay. We'll see.

Tuesday, June 14, 2011

Tree Platters

These platters are about 24 inches wide. They can be used to serve food and/or to accent a space on your wall. Cost: $350. The trees are individually stamped into the clay using my own stamps. The design in the center is a triskele, an ancient design representing the underworld, the middle world and the upper world, corresponding with the roots, trunks and limbs of the trees.

Monday, June 13, 2011

Electric Peek

I've never done this before, but it's such a sweet-looking platter.... Here's a sneak peek into the electric kiln at around 600 degrees.

A translucent blue glaze over Little Loafer's Glory,
a fine white clay from Highwater Clays in Asheville.

And here's five bowls using the same clay, stamped
with one of my tree stamps.

Saturday, June 11, 2011

New Work for the Wood Kiln

Just a quick update:

Levi and I are planning on firing the wood kiln this month with three large pots Levi created recently. Actually, they've been sitting and waiting to be loaded for a couple of months now. They'll take up most of the space in the kiln, so we've been making some smaller pieces to fill in around them such as small mugs, soul pots and tree vases.

I spent much of last week cutting and stacking wood, as Levi made pots. I reached a point where I was sick and tired of electric saws and wood slabs and pallet parts and spent a couple of days recently making some large soul pots and a few pieces that customers ordered.

Our next show is Art in the Park July 16 in Blowing Rock.

Four tall pieces Levi made for the wood kiln

Recent work for the wood kiln

Levi brushes a flashing slip on a tall vase