Wednesday, June 13, 2012

Campfire Pottery

My last 2 campfirings yielded very different results. I decided it might be fun to bust up a pretty budlight platinum bottle - very blue- add some borax and see if I could get it to melt.
Welllllll... it melted, a little, in chunks. Fused some. But, the mule team borax melted in a nice puddle in one of the pots.  Glaze, actually. But, the pots cracked completely and fell apart. No good.

So, I decided that maybe if I wedged (mixed for you nonpotters) some borax into the clay, it might help it to melt at a lower temp- this clay is very sandy and kind of short (cracky) so improving that would be good, but it wasn't as much my motivation as trying to get the pots to crack less in the firing.

I'm pleased that mixing in the borax actually did improve the workability of the wet clay, which was a pleasant unexpected bonus. Too much borax actually made it too sticky and wimpy, so there is a limit.

The last firing I did yielded some really beautiful orange pots with only a couple of cracks in the rim, and I was pretty aggressive in shoving them into the coals.  I preheated the pots for about an hour at the edge of the fire, and then just shoved them under the logs. They weren't even buried in coals, so I'm wondering if there was a temp. difference which caused the cracks.  I am, however, pretty pleased with the results. 

My next plan is to mix some salt along with the borax into the clay and see what happens. Stay tuned. Camp starts next week!

Tuesday, May 01, 2012

I am very pleased with my new lace pottery dinnerware. Each piece came through the glaze firing beautifully. This tableware is thrown on the potter's wheel and made from food safe clay and glaze. They'll be tested in my kitchen before I offer these in sets for sale. This evening, they passed the steak test. yum.

Tuesday, April 17, 2012

Lace Pottery Thrown on the Wheel

I'm so excited about these I couldn't wait until they were fired to share them. I made a set of battenburg lace printed plates on the wheel. I love how this dogwood pattern takes waterfall brown glaze- the glazed plate shown is slab built, but I wanted to do them on the wheel. I'm pleased so far. If they turn out well, the first set is mine!

Monday, April 09, 2012

Primitive Back Yard Firing #2-

No cracks on this one- Sandy clay, right from the ground, no additional sand added.

Wednesday, April 04, 2012

Primitive Firing- Making Pottery Without a Kiln

Success! I fired my "homemade" clay-(see my previous post for directions to dig and screen your own clay)- in my little backyard fireplace. I learned so much and it was really fun so I plan to do it again soon. Besides, I've got 15 lbs of clay to play with.
If you try this, BE SAFE. Two of the pots exploded- not a project for kids without close adult supervision, and safe practices- protective clothing, face gear, tongs, gloves- you get the picture.
My initial feelings after reading a few articles and having a few failures was that moisture was my enemy. That seems to be only part of the issue. Thermal shock also matters big time. The 2 pots that survived had alot of sand in the clay- some of which came from the ground already in the clay, some of which I added to one of the pots. Too much sand and the clay is "short" or cracks easily as you work it. The pots that made it were kind of cracky, but I could still throw the clay on the wheel. I will add ball clay to my next batch (to make it more plastic) and see what happens.
Another thing I learned was to be patient in preheating the pots. I did kind of just put a couple right into the coals, and they blew up within 5 minutes. So, the others were put along the side of the fire and gradually moved in over probably an hour to 90 minutes time. So, I guess patience is my and learn.
Here's a link to a slideshow with more pics and notes on the process:

Sunday, April 01, 2012

Pottery "From the Ground Up"

I have recently become interested in making pottery without using a kiln. This summer I am teaching a pottery class at Camp Asbury titled "From the Ground Up." The focus is on making tools, preparing clay from the ground, and primitive firing.

Step 1. Clay. Easy to find in Ohio, just dig a hole and it's there. Step 2. Let it DRY. Completely. Then, add water and it will disintegrate and slake down into fine mud. Mix it up, and screen through an old metal window screen to remove, sticks, stones, stuff you don't want in your clay. Step 3. Dry your slurry into workable clay. This can be done by putting the slurry in an old pillowcase and leave it out on the concrete. I have a plaster top wedging table where I dry my clay. Hardi backer cement board or old drywall would also make a good surface. NOTE: if you use a plaster surface, DO NOT get plaster into the clay.
Once the clay is a workable consistency- test it by squishing it up until it feels right. Then, you can make some pinch or slab pots from the clay. I made 4 pots for my first test firing.
Pot (A) is homemade clay with white stoneware mixed in and "marbled."
Pot (B) has brown stoneware added, because I felt the clay right from the ground was a bit cracky, or short.
Pot (C) has some sand added to the clay, which made it even more cracky.
Pot (D) has nothing added and is thrown on the potter's wheel.
I tried to keep the pots even in thickness, no thinner than 3/8" - 1/2". Also, I have placed the pots in my kiln to preheat at 200 degrees for several hours. I have never successfully fired green clay in an open fire without cracks and explosions. I'm convinced that moisture is my enemy. Smarter people than I have been doing this for thousands of years, so what's my problem?? My attempt to be SURE that the pots are really dry is to preheat them for several hours in my kiln. This could also be done in an oven.
Keeping my fingers crossed and hoping to have pics of fired, undamaged pots later!