I thought I would do a progressive photo article on making a LARGE round pot.
A few years ago I received a commission for a round pot that would be the biggest I had thrown on a wheel up to that point. The customer gave me the INSIDE diameter and depth that he wanted and explained that he wanted it made from stoneware and finished as some of mine he had seen that I had made in smaller versions.
After calculating out shrinkage for the clay I was using I began the job. This calculation is important as most stoneware clays shrink 10-13% during drying and firing and you must figure out just how big you need to make the pot to arrive at the desired size after all of the firing is finished.
I then needed to figure out about how much clay I’d need for the pot and started to center it on the wheel. I started with 50 pounds of clay which is a job to center!
After centering I began to expand the ball and open it up.
As I expanded the pot I had to constantly keep in mind the size and depth I needed to throw to arrive at the correct commissioned size after drying and firing.
Please note that the bat I am throwing on is 24 INCHES IN DIAMETER!
After I got the walls and bottom the thickness I wanted I then trimmed the rim to the height I needed.
After a couple days of slow drying the pot became the right level of ‘leather hardness’ so I could carefully flip it over and trim the bottom and add some decoration to the sides. On pots over 12 inches I trim in an inner ring that helps support the pot while drying/firing and helps keep it from cracking while drying/firing. Here are some shots of the pot being trimmed.
Pots this size and weight can be a challenge to flip during construction, finishing and drying. Some pots require flipping many times. Try thinking about holding a 24 inch/50 pound pot between two pieces of board out in front of you and flipping it over quickly without dropping it! This is accomplished by two people placing boards on both sides and quickly flipping it as you press on the boards. To make it even more difficult it is often placed on layers of slippery plastic which acts as a slide bearing while the pot is shrinking during drying.
Here are some shots of me flipping a different large oval pot I constructed. The photos explain the process pretty well.
Here are a few photos of the pot after trimming is complete and drainage/wiring holes added and signature. I have also added a band around the outside of the pot rim in a contrasting color of clay as the customer desired. This takes quite a while to do neatly.
The next photo shows the pot coming out of the kiln after being bisque fired to around cone 04. This burns impurities out of the clay, and makes it easy to handle and to finish with stains or glaze. This bisque firing is to around 1,920 degrees F and leaves the clay in hardness and porosity similar to terra cotta pots.
The next photo shows the pot after applying an oxide wash to darken and enhance the color of the clay during high firing.
The next three photos show the pot after high firing to cone 10 (about 2,350 degrees F.) in my gas kiln. This leaves the stoneware clay with only a slight amount of absorption (of water) which makes it fairly safe to use as a bonsai pot and fill with soil which might freeze in the winter. If practicing bonsai in a climate that will allow pots to freeze it is very important that they be made from a good quality clay that is fired to maturity which will leave it ( and the glaze if used) , in a glass-like state that is mostly unable to absorb water. We call this ‘Vitrification’. A vitrified pot is very important in cold climates but lower fired pots with more absorption to the clay can be used in warmer climates where freezing is not a concern. However, quality clays and matured clay firing levels are desired so your pots don’t absorb too much water and leave salts, etc. dried on the outside surface.
You can see some firing marks on this pot where flames were hitting the sides of the pot. This is a great effect which I feel is desirable and I suggested that this be the ‘front’ side of the pot when the tree was potted.
The next two photos are of me holding the pot so as to give you a good finished scale view.
This large pot has been potted with the intended tree for about 3 years now. It is a very large San Jose Juniper. Here is a photo from 2010 winter in storage. I hope to see the tree in a symposium bonsai display within the next few years. The owner says it’s getting close to being ready to show.
Here are a few other photos of customer’s large commissioned pots that I’ve made over the last few years. They are potted with their trees. These are all in the 16 inch to 21 inch range.
I hope you enjoyed this brief view of making a large wheel-thrown bonsai pot.
Dale, I really enjoyed the article. I knew that pot as your profile picture on fb, but the true story behind this massive pot I didn’t know. Looks like a lot of work is put in this pot, good work!
Thanks Youri,
I’m glad you liked it.
I often get comments from non-potters about how they never realized how much work it all was or how risky they often are to get completely finished. I always tell folks that it’s not a Bonsai Pot until it comes out of the LAST firing OK.
Although I probably shouldn’t mention the tree owners name online, he did tell me that he purchased the San Jose from Mike Levin at Bonsai West and that it came from a Japanese grower on the west coast.
Hey Dale…
Enjoyed your posting !!
I wonder how many pounds of clay would it take for a Cypress?
Best Always
Gary
Gary,
I guess that depends on the size of the cypress!?
There is a limit to what I can throw on my wheel, handle and fire in my kiln. This is about it!
Dale,
You’re a big boy…you need to think larger…larger wheel…larger kiln…lower prices.
Gary, at 62 I’m as large as I want to be ( in every way! :>) )
I am nursing my electric kiln along so as not to have to replace it before I retire.
Wheels don’t really get bigger, just the bats you throw on. They do a bit bigger in horsepower but I am already exceeding my motors weight with no probs. But at 24″ I’ve found that as my max for FLIPPING. There is only so much weight you can hold out in front of you and flip! :>)
Larger kiln does NOT equal lower prices.
BTW, I HAVE been thinking smaller since I dug that Bald Cypress with you. It almost killed me!
Dale, beautiful work. A suggestion on a safer way of flipping your larger pots.Take two pcs. of plywood that you use to flip your work, drill 5/16 holes @ corners for threaded rod ,center a large wooden dowel @ right angels on one pc. of plywood and firmly screw. fashion pillow blocks to fit dowel. Screw pillow blocks to saw horses. pillow blocks should have removable tops. Space saw horses ,attach plywood with dowel onto pillow blocks .Shore up plywood assembly so it won’t spin.Place pot and clamp other pc. of plywood with threaded rod and nuts. Happy flipping!
Fabulous posting. I’ve been attempting to make “larger” bonsai pots for myself and others over the last year or so. Mainly teaching myself. Made lots and lots of mistakes, so this is most helpful! Its great to have some potters willing to share their craft.
Fiona,
I taught myself. I made a few in college, small stuff, about 35 years ago! Had to buy EVERYTHING I needed as I went when I started in 1998. No College equipment for me to use.
I didn’t know you’d been potting. You should show some on IBC. Europe can always use more potters! :>)
I’ve ALWAYS shared my craft, I used to be a public school teacher in another time, it just depends on who you ask if I do it enough :>(
Cool post Dale-
I definitely understand what you mean by EVERYTHING being spent on your business. I am in the same boat, what with having already spent up to 15 grand of my own money on equipment AND materials/supplies.
Anyhoo,
Hope to see more informative articles from you again…
Peace,
Rob Addonizio
Very cool! I actually read this, then read it again! The pot featured is very beautiful.
Ken,
Wow! A double-read! Thanks.
I’m glad you enjoyed it.
I might work on a few others.
Very great job Dale, thank you for sharing your artwork.
Regards,
Giang
I dream of a day when I have trees worthy of pots such as that.
Dale… I LOVE this article… I have seen and known a lot about this pot from when you did it, but seeing it all together in one place, I love it!!
You still have the most beautiful bottom(s) I’ve ever seen. lol
Luv yah,
V
Thanks Guys.
Vic, I’m glad you like my bottom(s) :>)
I hope you read my two tree photo essays and watched the two carving tool videos.
Dale