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.

11 thoughts on “Firing for anyone”

  1. Thanks for sharing !
    I’m curious to know if the work fired with this technique is fully functional or if it has the same functional limitations as raku ware? (beginner question)

    1. Fully functional! If….you make sure temp is reached for a long enough time. It’s not as tight as a full 18 hour cone 10 firing, and it really depends on the clay you use. I use VERY short, sandy clay to avoid breakage, and it needs a full 30 minutes when the kiln is preheated. For the first piece of the day, I always add 15 – 20 minutes to the firing time, because the kiln isn’t as hot for as long. These firings usual reach 1300C, so are plenty hot to seal the clay body.

  2. Wonderful post. I have experimented with this some, but my results haven’t been great. Can you tell me more about what type of clay body I should use? Also, do the pieces need to be bisque fired first? You also mentioned polishing finished pieces. What type of polishing is necessary? Thanks for the inspiration.

    1. Hi Matt, I’d recommend something very short and sandy, and yes, I always bisque first for this sort of fast firing. I use diamond pads to polish, whatever it takes to knock off the sharp edges. Usually 400 or 800 grit is fine enough not to leave scratches on unglazed ware. For glazed I usually go up to 1500 or 3000 grit.

  3. Thanks for the response. Sorry, one last question. Can you tell me where you picked up your shichirin? Anything I find online looks to be way smaller than what you are using. I’ve made a handful of small sake cups that I want to burn 🙂

  4. Hi Matt,
    Sorry, this answer probably won’t help much, but I got mine at the local hardware store, the caveat being that I live in Japan where all hardware stores carry them.
    The ones I use are about 25cm wide.

  5. Hi I’m an aspiring potter that mostly takes classes at a local pottery hub and I’m looking for ways to fire my wares when I’m not taking classes and I have always been curious about firing with shichirin. This is one of the few resources i could find on the subject so really appreciate your insight. My question for you is: what are the dimensions of the shichirin that you use? I have a goo d amount of experience in firing many different techniques and atmospheres but I’m having a hard time finding what size shichirin to start with any response or further advice would be much appreciated.

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