Tag Archives: teabowl

Firing for anyone

In Japan, people often visit pottery studios for a short pottery experience, either painting something or making something small to be glazed and fired later by the studio owner or a craftsman. This has always seemed so limited to me, and the inevitable comment, “Oh, you are so lucky, I wish I could do this every day!” always prompts my response: “Yes, me too!”. Most people just don’t have any idea what goes into a finished pot. Turning it on the wheel is maybe 10% of the overall process, much less if you gather materials yourself and/or wood fire  your work. And customers rarely see the failures, or all the polishing that goes into a piece and assume the potter just opens  the kiln door to a batch of warm, super looking, ready to sell pots.

Finding a way for people to experience more of pottery making is a challenge, because of the time it takes drying, bisqueing, firing, and waiting to cool down. Raku firing abbreviates this a lot, but still requires a lot of specialized equipment in most cases. Shichirin fired pottery, for me, is a good way for anyone to have a firing experience, including the excitement of the fire, the engagement with the work, the post fire polishing and critiquing, and even the failures and serendipitous successes.

Lately I’ve been working on a firing method that is accessible to everyone, with items available at most home centers. I got this idea years ago when a Japanese potter named Yoshida (don’t remember his first name) made a splash by introducing “Shichirin Togei”, which used a  small Japanese BBQ, called a shichirin, to fire small objects. This developed into a book called Minigama, which I never read, but outlines the construction of small handbuilt kilns from fireclay and fired with wood, charcoal, and forced air. I think the book is out of print now.

I liked the idea of shichirin togei, but thought the open shichirin was maybe not so efficient at getting up to temp, so I added another one on top, like a clamshell, with both shichirin wadded together with a coil of clay. The bottom damper is the air port, and the top damper is the chimney opening and stoke hole.

You start by packing some charcoal into the bottom of the chamber, around a stilt on which the pot will sit. Then place the pot on the stilt and continue covering with charcoal. Then place a coil of soft clay around the mouth of the shichirin, and overturn the second shichirin over it.

Now that that is done, time for the fun to start! Use a hand torch to light charcoal, then use a hair dryer to get things burning hot.

Now just wait for things to heat up, it will take a few minutes, after which flames will start to emerge from the top damper hole.

This flame should continue to grow and get jumpy, making noise as unburnt gases from inside the chamber exit and combust when they meet more oxygen.  Keep slowly adding pieces of charcoal from the top stoke hole (damper), keep that flame extended. As it gets nice and hot, you’ll be able to tell how the kiln breathes every time you put in a piece of charcoal, and you’ll get a sense of when to stoke.

The first firing might take about 45 minutes, because of the time to heat everything up. From the second firing, 30 minutes seems to be enough to fire the clay. If you have time, you can go longer, and ash from the charcoal will leave more green ‘glaze’ on the surface of the pot.

Gas Firing 2016.02.20 Comments and Notes

This firing of the kiln went too long, resulting in Orton cone 11 flat.  Ideally, it would be cone 11 touching, then sagging a bit.

Upon unloading the kiln this morning, one thing was immediately apparent: the right side was far more reduced than the left. Yellower glazes and more slumping. Even on the left side there was some slumping, because of the excessive temp., and because of the clay which contained some low temp high iron clay to help seal the ware against leakage.

Left side, sagging only slightly, white surface.
Left side, sagging only slightly, white surface.
Right side sagging badly, white glaze turned yellow.
Right side sagging badly, white glaze turned yellow.

Chosen Karatsu came out pretty good, but the white was on too heavy, running down the pots too much.  It still came out looking ok because of the clay.

Most of the teabowls warped or sagged, so I only get to keep 2 or 3 of the 15. This is why teabowls are expensive, kids…IMG_3399 IMG_3398

All in all, not a bad firing, but need to adjust clay bodies, and pay closer attention to cones. Also, figure out the over reduction on the right side. It might be that one burner that sounds a bit off.

Kakewake CG bowls
Kakewake CG bowls
guinomi, need more sand in the clay
guinomi, need more sand in the clay
crystals, only grew on the right side, where reduction was strongest.
crystals, only grew on the right side, where reduction was strongest.
cylindrical tea bowls
cylindrical tea bowls
yunomi
yunomi
shells on feet
shells on feet

IMG_3437

saggared and much improved.
saggared and much improved.
porcelain, saggared
porcelain, saggared

IMG_3464 IMG_3463 IMG_3462 IMG_3460 IMG_3459

 

2015 Christmas Firing

was a real nail biter.  At 4am, 10 hours into the firing, I realized that I had not gauged my propane reserves properly, when I looked at the tanks and realized that they were only about 1/5 full and covered with a thick layer of ice. I immediately put the water hose on them to melt the ice and keep them from freezing again, then I chewed my nails until 8:30 am when I could finally call the gas company for fresh tanks. They arrived just after 9am, and good thing to because I only had about 2 inches of fuel left in the tanks at that point.

The firing ran a total of about 18 hours, which is fairly normal for this type of firing, and most things came out ok, with a few exceptions:

Fall Open Studio

Just a short post of some pictures from the studio sale this weekend.

Coil and paddle

I have been working on coil and paddle pots these last few days. This is a sequence of photos from a jar I made today. It’s not very big, probably about 36 cm across.


  
  
  
  
  

Rainy Season Is Here

A lot has happened over the last month since the Karatsu pottery festival, mostly cleaning, shelf building, and shifting things around in the studio in preparation for the open studio event which happened this last weekend from June 19th to June 21st.

In rough chronological order, here is what has happened in May:

Plates formed over wood slabs of various sizes

Paddled slab plates en masse...
Paddled slab plates en masse…

We got our garden planted and our first Jalapenos soon followed!

This year's small Jalapeno crop. Not many, but it's a start.
This year’s small Jalapeno crop. Not many, but it’s a start.

Another type of crop: Good batch of Madara Karatsu guinomi from late April firing. Body is mostly crushed sandstone with a bit of native low iron clay to help keep things together.

Madara Karatsu guinomi from spring gas firing.
Madara Karatsu guinomi from spring gas firing.

In prep for the open studio event, I cleaned the deck and brickwork of the backyard. I did not realize just how overgrown with algae and moss it had become until it was clean again.

The deck and bricks after being power washed. Almost like a new backyard.
The deck and bricks after being power washed. Almost like a new backyard.

One of the worst sections, but it felt really cathartic blasting all of that green away, leaving nice clean trails of clear, brown wood.

Before After pic of the deck, what a difference!
Before After pic of the deck, what a difference!

Entrance to the yard event space, tents and blue tarps up to  keep out the rain. Luckily, although it threatened a few times, it never really rained, and the last day was actually sunny and hot. This is  the middle of monsoon season folks, we totally lucked out.

Emeth and Shimauchi san's burgers. Best burgers in Nagasaki. Best burgers in Saga for 3 days only.
Emeth and Shimauchi san’s burgers. Best burgers in Nagasaki. Best burgers in Saga for 3 days only.

The spot for gamblers. 500 yen per turn, no losers. One grand prize, 15 second place prizes, 25 3rd place prizes, and 100 4th place prizes. One grand prize went out every single day of the 3 day event. Happy customers!

Pot lottery wheel. No losers here, everyone walks away with a pot, some better than others...
Pot lottery wheel. No losers here, everyone walks away with a pot, some better than others…

This discount table was a new strategy for me. Turned out to be great for turning older pots into cash and additional storage space in my studio showroom.

My discount table, holding everything I haven't sold in 6 years that I couldn't bear to hammer. I think about 300 of these pots found new homes.
My discount table, holding everything I haven’t sold in 6 years that I couldn’t bear to hammer. I think about 300 of these pots found new homes.

Knife and tool maker, really nice stuff for reasonable prices

Knives and tools from Matsubara forge, in Nagasaki.
Knives and tools from Matsubara forge, in Nagasaki.

Really big caterpillar!

A friend I discovered during the open studio event. Never seen one like this before.
A friend I discovered during the open studio event. Never seen one like this before.