I've been working with a new clay body (for me) - B-Mix with grog from Aardvark. It works well for large pots. This vase is 19 inches tall.
The vase is flanked by some wine coolers (bisque-fired pots that can be soaked in water and will keep a wine bottle cool after it has been opened).
The vase was glazed with Orange Shino glaze from Aardvark. The top part of the vase was glazed with Snow Cap Shino, a simple glaze from Tom Coleman's glaze book. The Orange Shino glaze on B-mix is orange when it is thin but has a metallic sheen when it is thicker. The bowl shown below is another example.
The bowl is shown on a wooden coffee table. The bowl was glazed by spinning it on a wheel and pouring the glaze into it. The bowl continued to spin while the glaze dried so the glaze was thinner on the bottom of the bowl than on the sides. You can see that the bowl is orange on the bottom. Before firing I placed some peanut shells in the bowl. Here is a view of the bowl from the top.
Here are a few of my pots that were fired at the workshop.
They had an interesting glaze at the workshop. It was nominally called a blue matte glaze but, as you can see, it shows flashes of red when reduced. I wish I could get that glaze.
This bowl is 13.5 inches wide at the top and 7 inches tall. It was thrown using Vegas Buff clay from Aardvark and glazed with Orange Shino glaze.
This vase was thrown using Coleman Porcelain. It sagged in an interesting way. The glaze is Vegas Red.
I attended a workshop at the office of Geil Kilns in Huntington Beach, CA, on the weekend of January 28-30, 2012. The weekend was fun, informative and sometimes even exciting.
On Saturday morning we gathered and met the other participants. We had people from British Columbia, Canada, and as far away as Detroit, Michigan. Many were teachers who came to learn more about firing their Geil kiln. Some were like me, retired or soon-to-be retired. One was a local young man, Zac Hould.
We all brought some bisque ware to be glazed and fired during the workshop. Tom Coleman demonstrated the use of a spray gun to glaze pots. I had tried it on my own before but thought it was too much extra work. Now I have a better idea of how to use a spray gun. It is really the only method to use when you have a large pot to glaze.
Tom also introduced us to shino glazes with added decorations like "crocus martus", a very fine form of iron. It can add shiny rust-red high-lights to a shino-glazed pot. Peanut shells on a shino-glazed pot can also introduce interesting designs.
After we all glazed our pots Paul Geil demonstrated how to properly load the kiln. This was a big revelation to me. I had been loading the kiln with two stacks of shelves running side-by-side lengthwise into the kiln. (You can see some pictures of previous firings in previous blog entries.) The better way is to turn those 2 shelf stacks by 90 degrees so the shelves run side to side instead of front to back. Then you can place pots in front of the flew hole to partially block it. That causes the hot air to work its way around the pots before going up the chimney - it can not head straight for the flew opening without warming any pots. This new stacking method should solve some of my heating problems. Paul and Tom also stressed that the kiln should be as full as possible.
After the kiln was loaded Paul showed how to start a glaze firing. The Geil kilns come with a controller that allows you to set a target temperature and a time interval. The controller will then adjust the gas gas flow to raise the temperature to the desired level within the specified time. (I simplify the controller here. You can actually set multiple times and targets.) Paul set the controller to heat the kiln to 1700 degrees over night, about 15 hours. We could then all leave for the night and come back the next day with the kiln primed to finish the cone 10 firing. No one needs to watch it and make adjustments during the night.
The next day, Sunday, we finished the firing. Paul demonstrated how to finish a cone 10 reduction firing manually - by-passing the controller. This was also a revelation for me. I had previously relied on the controller for the entire firing. Paul demonstrated how to test for proper reduction. After making the initial damper and gas flow adjustments there were surprisingly few changes made during the remainder of the firing.
Paul noted the temperature about every half hour and started checking the cones (top and bottom) when the temperature reached about 2000 degrees. He also tested the back-pressure (flames coming from the peep-holes) from time to time and adjusted the damper a little (one-eighth inch adjustments) from time to time. The damper started at 2 and one-eighth inches and ended at 2 and one-half inches -- very small changes. When I allowed the controller to control the firing, it moved the damper a LOT. I plan to over-ride the controller on my next firing.
The firing was complete by 1 PM on Sunday. We just had to wait til the next morning to see the results.
While we were watching the kiln get hot and then cool down, Tom Coleman demonstrated some throwing and decorating techniques. I enjoy watching master potters do their thing. Here are a few of the pots he produced:
Tom's technique is quite different from Claudio's but both achieve wonderful results. (See previous blog entries concerning Claudio Reginato, the Italian master potter.)
The exciting moment was Monday morning, the opening of the kiln. I was quite pleased with some of my pieces. I'll share them in the next blog entry.
We only get about 2 inches of precipitation a year here in Henderson, NV, so when it rains I like to capture as much water as I can. I use it to water the potted flowers. I made this "rain catcher" pot and I set it to catch the run-off from the roof.
The rain catcher is 19 inches tall and 9.5 inches in diameter at the top.
It works well. We just had our first rain in a couple of months. It lasted about 5 minutes and didn't fully wet the street. Fifteen minutes after the shower the streets were dry again but the rain catcher was nearly full.
As you may have read, I've been trying to glaze some pots with a red glaze (see "Vegas Red ... or not") but have not had a lot of success. I decided to try a different glaze formulated by Dan Dermer. (See Higher Fire Studios)
Before moving away from the Bay Area (San Jose, CA) I asked Joanne at Blossom Hills Crafts for the formulas she uses for her glazes. She was kind enough to provide them and more. She also gave me some glaze formulas by Dan. His "Copper Red" seems to work well in my kiln. And it works on different clay bodies.
Copper Red on Long Beach
This goblet is 6 inches high and 4 inches in diameter. The Copper Red glaze was applied by dipping. The iron in the Long Beach clay body does burn through the glaze a little where the glaze is thin but the color you see is definitely red.
Copper Red on Colman Porcelain
This vase is 9.75 inches tall and 3.5 inches in diameter. The glaze was applied by spraying. The thickness was not uniform so I'm showing two sides.
Copper Red on Vegas Buff
I saved the best for last.
This vase is 8.5 inches tall and 6 inches in diameter. The bottom part is glazed with "Leach White", another glaze formula from Dan Dermer. The inside was glazed with a clear glaze. The Copper Red was sprayed on, the other glazes were poured and dipped.
Dan's Cone 10 Copper Red Formula
Dan has consented to share his Copper Red formula with the world. So here it is:
The basic glaze is this:
| Component | Percentage by weight |
|---|---|
| Gerstley Borate | 11.79% |
| Whiting (Calcium Carbonate) | 13.62% |
| Custer Feldspar | 13.01% |
| Nepheline Syenite | 29.20% |
| EPK (pulverized Kaolin) | 1.70% |
| Flint (Silica 200) | 30.68% |
That totals to 100%. Then add these colorants:
| Tin Oxide | 1.75% |
| Copper Carbonate | 0.50% |
NOTE:
The glaze does require a reduction firing to cone 10 (about 2320 degrees F) and it will run if applied too thickly.
I did another glaze firing in October. (Busy with family and friends and holidays since then.) Several of the pots were glazed similarly. Ida's White is a glaze formula that I got from the Blossom Hills Crafts studio in Los Gatos, CA. It produces a creamy white mat surface. Adding some red iron oxide (RIO) results in a beige color. I added a little too much RIO so the fired glaze was a pretty dark beige - more like brown.
I applied the glazes by dipping. Where the Beige and Ida's white overlap the color is a lighter beige.
A Vase/Jar
The dark spots (freckles) are caused by the iron in the clay body - "Long Beach" from Aardvark.
A Bowl
This one doesn't have freckles because the clay body, "Hopkin's White" from Aardvark, doesn't have iron in it.
Another view:
A Pasta Bowl
A Pitcher
One of the glazes sold by Aardvark is called "Vegas Red". It's one of the glazes formulated by Tom Coleman, a local pottery expert. It needs to be fired in a reduction (oxygen starved) environment. So far, I have not had much success.
I tried to do a reduction firing a couple of months ago and the Vegas Red pots came out mostly gray (with hints of red).
Last week I tried a firing procedure used by the University Of California at San Diego's ceramics studio. They have a Geil kiln with an atmosphere controller. That's what I have. The difference is that their's is a DLB-40S (See http://kilns.com) and mine is a smaller DL-18F so I was not surprised when their firing procedure did not work for me. My kiln did not reach the desired temperature within the time allotted so I extended the time. Some of the pots came out mostly gray again.
One of the pots was a large bowl (12 cm high, 32.5 cm wide). Although it did not come out all red it did come out looking good. Here it is. It is resting on a black and white granite counter top.
Top View
Side View
The bowl was thrown using T2 clay from Clay Planet (in San Jose, CA). It is a smooth, tan clay body. The iron from the clay body caused the dark streaks.
I'll try another Vegas Red firing some time but for now I am avoiding it. I'd be interested in hearing how other potters are getting high-fired red results.
We lived in Illinois one year before moving to California. We were near the Haeger Pottery factory. They produced slip cast vases with vivid colors. We bought 2 of them. One was a tall orange pitcher. We moved that pitcher from old home to new home 5 times before it finally broke. That pitcher was the inspiration for the pitcher shown above. This pitcher is 13.5 inches high and about 4.5 inches wide at the widest point.
For the other potters reading this, notice the spout. I call it a potter's joke because the spout is the natural result of throwing a pot slightly off center. I didn't know that when we got that pitcher from Haeger Pottery but I recognize it now.
I made a vase in the traditional Grecian urn shape and added the handles to make it look even more like a Grecian urn. It is 10 inches tall, about 3.5 inches wide at the base and 6 inches wide at the widest point (not counting the handles). It is 9 inches wide from handle to handle. The clay body is Long Beach. The handles, rim and stripe were glazed with Tenmoku then everything was dipped in clear glaze. The clear seems to come out gray and it changes the Tenmoku from a dark red to a black. I like the result.
