Making a LARGE custom pot

[Dale Cochoy]

As most of you know ( or should if you read my opening introduction )I am a potter who makes one-of-a-kind stoneware pots for bonsai. I make both traditional and contemporary styles. One of the large parts of my Yakimono no Kokoro pottery business is making custom pots specifically designed for a customers tree. I often take up the challenge to throw or build a pot in a specific color, finish and size to fit a customers existing potted tree or one that will soon be going into a pot.
This is a brief photo show of a large pot I built to a customers specs for a large Shimpaku juniper.
He wanted a round unglazed pot ,with a slightly contrasting textured band on the side that measured 20" INSIDE and 4" deep INSIDE. So, after calculating the size I needed to throw I then calculated approximately how much clay I needed to accomplish it. I needed 50 POUNDS of clay!!
I began. I used my biggest 24" bat to throw on....very carefully and slowly!
First 6 shots are centering the 50 pounds of clay and pulling out the sides and pulling up the wall.

 

[Dale Cochoy]

pot part2

After the pot was thrown it had to be cut from the wheel and dried for a few days before I could trim and decorate it.
Here is where I started having REAL problems!
The pot needed to be "Flipped" several times during working/drying so I had two 2ft X 2ft pieces of plywood cut to flip it back and forth.
Well.... I couldn't do it myself!
It was about 45 pounds of wet clay ( after throwing) on a 24" plywood and formica-faced bat that weighs about 15+ pounds and a 2'X2' plywood slab that weighs about another 15 all in a pile. I couldn't hold in one hand and flip onto other hand!! So, I had to get my wife to help each time I needed to flip w/ each of us with one hand on top and one on bottom!
It was a mini-heart attack at each flipping!! I prayed it wouldn't slide out or we would drop it!
you can see in the sequence of pictures during trimming the bottom and decorating the side with band that I removed probably another 5ish pounds of clay in trimming. I also used an old trick for large pots in which I left a secondary foot ring about mid-span to help with sagging in drying/firing and cracking in drying/firing. This secondary foot ring also allows water to drain.
Please notice that the inverted pot barely fits on the 24" bat!!

 

[Dale Cochoy]

After much flipping and drying for over a month the pot goes into kiln for bisque fire. Up until now it is merely dry clay and requires VERY CAREFUL handly for something that size/weight.
After Bisque firing I can more easily handle it and coloration is applied. Plus a couple new tricks I thought up.
Then it goes into final high fire. Here's a shot at night during reduction firing.

 

[Dale Cochoy]

Pot last page

Here are a few shots of the finished pot.
It measures 22" X 5" outside and 21" X 4" inside.
I'm not sure how much it weighs now!
Note: During firing one burner scorched about a 7" part of the side. I REALLY like these types of flaws in firing and If my pot I would probably pot using this view as the front,
but most would like the flawless side view.

I've enclosed a few photos of me holding the finished pot for scale. The customers tree has been potted in this pot for almost two years now and is doing fine, unfortunaley, even though I am promised, I rarely get photos of peoples potted trees once they receive the pots.

I hope you enjoyed this brief view of making a large pot.
Regards,
Dale

 

[Chris Johnston]

Wow, Dale, that's impressive! Those who have never thrown a pot can't understand the amount of force needed to center that much clay.

How much bigger than the finished product did you need to throw the pot to allow for shrinkage? and can you give us a little better detail on the textured band?

What amazed me was how much bigger the pot seemed in the photo with you in it than without. I think that says a lot for the proportions of the pot.

Great job and great post!

 

[Chris Johnston]

LOL I didn't realize you were still posting here when I replied.

 

[Anonymous User]

I like the thought that went into the design of the "legs" on the bottom, plenty of area for excess water to drain away.

You definitely work magic with pots Dale, and judging by the pictures, you're a real Hairy Potter of bonsai.


Will

 

[PeterW]

Great work.

Thanks for sharing that Dale. The proportions of the pot must be nea perfect! As stated by Chris, in the picture without anything to gauge the size of the thing, it could easily be a very small pot. Well done, you must get great satisfaction out of creating such a beautifull product.
Merry Christmas.
Peter

 

[Bill S]

Very nice Dale, more work than most would think.

Wish my boo boo's looked that good. Cool too that an event like that can make it "unique" and add provanance. I'd put that side where it would be seen.

 

[Dale Cochoy]

Thanks guys.
To answer Chris' question about figuring size.
Most of the clays I use have 10-12% shrinkage if fired to maturity ( a cone 10 clay fired to cone 10 for example). So, if making a round pot you can figure pretty close in what you need. Ditto with a slab built pot, you can figure the sizes of sides/bottom etc. before you start. The tough ones are the ovals. I keep a running chart for those which I add to everytime I make something different.
More than the problems figuring the sides are the problems figuring just how much clay you need when making something new. TOO MUCH is ok, you can use it later after you trim it off. TOO LITTLE is more problematic, that requires making another pot! That happens often.
I have three choices of a pot for a customer in the works right now. I'll post all three when they are all completed. All a tad different in size and style but same finish. You might get a better idea of how problematic it is when a customer wants a certain rim size, certain size inside top, certain size inside bottom ( different than top) and a certain foot design. Those are thrown VERY slowly and mostly figured out as I go. Much more difficult than a fixed size inside and depth that is the same diameter all the way to the bottom.

Sorry no better pictures of the band for Chris other than what I have. It is a decoration treatment I've used for about 8 years. Pretty time consuming, about the same as adding 'rivets'. I'd figure about another 45 minutes on that pot for that, possibly more if problems.

Also, Chris, centering is the most difficult part of throwing and the more clay....the tougher. 50 pounds takes a bit of pushin' and pullin'

BTW Bill, the owner used that "flashed" side as the front.....I talked him into it.

Regards,
Dale

 

[Chris Johnston]

Dale, how do you make that band? Or is that one of your trade secrets?

 

[irene_b]

Dale I have a few questions:
When you remove it from the wheel, just exactly how is that done?
What kinds of tools are used for the sides?
Why does it take so long to dry?
Can't it be dried in the oven?
When you start to fire the pots, is the heat graduated?
What does it mean when Fired to Cone 6?
Thank You for posting this!
Irene

 

[John Hill]

Fantastic Dale!! That is a monster!! Hey just one thing?

Why don't you smile

A Friend in bonsai
John

 

[Bonsai Nut]

What a great series of pics! Thanks for sharing, and just as important, thanks for taking the time to DOCUMENT your work! It must have been a hassle to stop so frequently and snap photos. This is why I love the Internet - it is the next best thing to being there...

Thanks again Dale!

 

[Tachigi]

Great documentation Dale. Centering must be a great cardiovascular work out with a 50 pound lump of clay. The picture of the kiln inside the building was a great shot! Because of the lighting, it immediately reminded me of a scene from Dr. Frankensteins laboratory. For some reason I have this mental picture of you standing in front of the kiln with a manical look saying "its alive". Which I assume wouldn't be to far off the mark with a 50 pound pot.

Great thread thanks.

 

[pjkatich]

Dale,

Thanks for sharing this informative pictorial, I enjoyed it very much. Having made a few bonsai pots myself, I understand exactly the difficulties you talked about. Most people do not fathom the effort required to produce a pot of this size. As always, your work is outstanding.

Happy Holidays,
Paul

 

[No it's not...]

Dale I have a few questions:
When you remove it from the wheel, just exactly how is that done?
What kinds of tools are used for the sides?
Why does it take so long to dry?
Can't it be dried in the oven?
When you start to fire the pots, is the heat graduated?
What does it mean when Fired to Cone 6?
Thank You for posting this!
Irene

I'm not Dale, but I think I can answer some of those (Dale, feel free to correct me if I'm wrong):

Why does it take so long to dry? Can't it be dried in the oven? Clay actually dries fast, but the slower you make let it dry the less it warps.

When you start to fire the pots, is the heat graduated? Yes.

What does it mean when Fired to Cone 6? This link explains it http://www.bigceramicstore.com/Information/ConeChart.html

 

[JasonG]

Hi Dale,

Excellent post! Thanks for taking the time to do this here and giving us all a glimpse of what it takes to make a custom pot. I am sure your customer was very pleased with the outcome of the pot, you did a wonderful job!

Thanks again for sharing!

Jason

 

[Dale Cochoy]

I'm not Dale, but I think I can answer some of those (Dale, feel free to correct me if I'm wrong):

Why does it take so long to dry? Can't it be dried in the oven? Clay actually dries fast, but the slower you make let it dry the less it warps.

When you start to fire the pots, is the heat graduated? Yes.

What does it mean when Fired to Cone 6? This link explains it http://www.bigceramicstore.com/Information/ConeChart.html

Cones:
The linked page is a typical pic of orten cones which is what we use to tell the heat/time relationship of our clay to the firing. All clays have a maturity temperature. If over fired past that they can warp, bubble and a few other things. If fired too low they won't reach the vitrification of the clay that we want or, sometimes, the color. Some clays have a wide range of where they can be fired. Temperature is only PART of the game, the time/heat relationship also come into play. As an example, if I wanted 2,000 degrees I could heat for 5 hours at 400 degrees, 10 hours at 200 degrees or I could heat for 20 hours at 100 degrees, or, I could vary those times/temps as I go along ( which is usually how its done). When the cone gets to the amount of "HEAT WORK" it needs to bend, it slowly does. We need to watch it closely then to tell when to shut down. This gets tricky as top and bottom of kiln sometimes are different temps and heat raises differently.
You place a series of increasing cones in a row and you watch as they go down until you get to the range you want. I'll take a picture of some old cones to show you.
Learning to fire, especially a kiln without a microprocessor takes some time....and ruined pots.
There are many reasons a pot can be ruined along it's journey through making, drying, firing, glazing. They are ALL upsetting but moreso in the last step.

Yes, heat slowly at first, then faster.

Drying is the downfall of many. If drying too fast you can warp or crack the ware ( usually crack).

The tools I use are common ceramic tools plus some specialty tools I make.

All potters have different ways to remove pots from the wheel. This pot was set on the bat a while to stiffen up, then cut with wire and flipped onto other bat. THIS is the tricky part because one person can't hold roughly 70+ pounds of pot and boards and flip it with one hand onto another board. It takes two people.....enter....the wife! .....with explatives

Chris, the band is made by applying slip while the pot is still damp.

 

[Dale Cochoy]

I went out to the kiln shed and took a couple pictures of some cone packs to help better explain cones.
There are two sets of cones from two different firings.
These are set in the top and bottom of the gas kiln ( or any other type of kiln). You view them , with lots of difficulty, through the peep holes. note: you can see peep holes in the earlier picture of the kiln at night with flames coming out of them. Watch your eyeballs and eyebrows!
You monitor them as you fire and make adjustments to air and fuel as you go.
If you look at the cone chart in the previous link you will note the temps that each cone bends when fired at different degrees/hour.
If you look at the cones on the packs the far left cone is cone 7, then 8, then 9, then 10 on the far right. These are fired to approximately cone 9 1/2.
The tough part.....getting them the same at the top and bottom of the kiln!