I'm an amateur potter

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Orange Shino on B-Mix

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.

Large Vase with wine coolers

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.

Orange Shino Bowl, side view

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.

Orange Shino Bowl, top view

2012-10-18 21:48:28 GMT Comments (0 total)
From the workshop

Here are a few of my pots that were fired at the workshop.

Blue Matt Vase

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.

Large Bowl

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.

Funky Red Vase view 1Funky Red Vase view 2

This vase was thrown using Coleman Porcelain. It sagged in an interesting way. The glaze is Vegas Red.

2012-02-06 01:16:04 GMT Comments (0 total)
Geil/Coleman Workshop - Jan, 2012

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:

Some Tom Coleman pottery

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.)

open kiln

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.

2012-02-10 16:19:44 GMT Comments (1 total)
Having the right tools
Nut driver with extension,wooden skewer,wrench
My kiln has not been performing well for about a year. It all started after I did a cone 10 glaze firing then immediately went on vacation. The firing was complete - all except cooling down the kiln. I closed the doors to the kiln room and left. That was a big mistake! The air flow through the kiln room was insufficient to cool things down at a reasonable rate so everything in the room got very hot. It was hot enough to cause plastic things in the room to deform - including the housing for the kiln controllers.
Since then I bought and installed new controllers but the replacements were different from the old controllers (which are no longer manufactured). After that I had trouble with cone 10 firings.
On February 4-6 I attended a workshop at the Geil Kilns home office in Huntington Beach, CA. (MORE ON THE WORKSHOP, LATER - IT WAS GREAT!) After some discussion with Paul Geil and Tom Coleman it was decided to increase the orifice size on my burners. The orifice is like a nut with threads on the outside and a small hole in the center. The gas passes through that small hole. The new orifices have a slightly larger hole. Paul provided the new orifices -- all I had to do was install them.
After looking at the burners I finally figured out what I needed to remove the old orifices and replace them with the new ones. The tools are pictured above.
The burners look like this:
full burner burner close-up

On the left is the full burner including an on/off valve at the bottom and a ceramic cylinder at the top. On the right is a close-up of the metallic housing in the middle where the orifice resides.
The ceramic top slides off after loosening the screw that holds it in place with the box-end wrench.
The orifice is screwed into the burner 10 inches below the floor of the kiln. I needed a 10-inch (or longer) extension for my nut driver. Removing the old orifices was then just a few twists of the nut driver.
Installing the new orifices was a little tricky. If I put the new orifice in the nut driver then tried to position the nut driver over the place where it needed to be screwed in, the orifice would fall out of the nut driver before it was in place. My first solution to the problem was to use a small piece of a post-it, the slightly sticky paper, to hold the orifice in the nut driver until it was in the correct position. This worked for some of the burners but not all. I had trouble finding the correct position on some of the burners. Then I found another solution. A 12-inch wooden skewer, the kind often used for Shish Kebabs, worked perfectly as a guide for the new orifice. The skewer fit through the hole in the orifice. I could put the skewer into the pipe where the orifice was going to go and drop the orifice over the skewer. It was then in the correct position. I could reach into the burner assembly with my fingers to get the screw started then remove the skewer and use the nut driver to tighten the orifice.
The new orifices are now installed and I will be doing a glaze firing soon.
2012-02-08 23:18:36 GMT Comments (0 total)
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Disclaimer: The opinions expressed here are mine and mine alone.