Minigama – Coil Building the New Mini Kiln

minigama the mini ceramic kiln

My concept sketch, or mini-miniagama.

This is my summer 24 project, and I will update this page as I progress.

Minigama

Another low-cost kiln worth taking a look at is the Tin Can Kiln, it has some clear similarities with the Minigama kiln:

Glowing read steel tin can pottery kiln

https://www.woodfireceramic.com/build-a-mini-tin-can-pottery-kiln/

Minigama – Coil Building the New Mini Kiln

The author and ceramist Akira Yoshida has written many books in Japanese, also about the Minigama and other mini-kilns. But I don’t read Japanese: https://www.amazon.com/stores/Akira-Yosida/author/B004LP9V1O

My interest started when I came across the English book “minigama”:

This small booklet, which I do believe only translates a small fraction of Mr. Akira’s know-how about Minigama’s. The booklet gives no hint if Mr. Akira is the inventor of this kiln or the story about its origin.

Here is the front cover of the English booklet:

Book: minigama, by Akira Yoshida

According to the descriptions in Akira Yoshida’s book, a Minigama is a small 50-centimeter pottery kiln hand-built with traditional Raku clay. After it’s dried and burned one’s, it’s ready to be used as a “one Sake cup” ceramic kiln, and can reach 1200 degrees Celsius in about 3 hours. This makes it an interesting quick low-cost test kiln. I guess the name Minigama is a humorous comment on the traditional Asian Anagama kiln, which it also borrows a few concepts from. To make sufficient airflow into this small kiln, it uses a hairdryer to blow air under the charcoal (the combustion material of choice). In my opinion, this simple idea combines traditional ceramic kiln concepts with ideas from the blacksmith. It’s such a simple construction, but it redefines the principles of the traditional pottery kiln. If a motor makes the pressure, you don’t need a draft, if you don’t need a draft, you don’t even need a pipe. Every wood-fired kiln tries to balance the air intake, the firebox, and the wares chamber, against the pipe, to make the right draft. But the hairdryer is the new kid on the block. The Minigama has absolutely some challenges of its own, blowing directly into the fire makes sparks spray around like a Fontane, and a kiln built in clay is just doomed to crack (or worse). Still, this is a dream come true. It is possible to model your own mini wood-fired kiln that works! (with some issues).

Read my review of the book here:

minigama review of the book

One question that makes the Minigama so interesting is why this small device can reach high temperatures in just three hours? Sure the hairdryer makes a fire on Steoroids. But that’s just part of the answer, and I think the thin walls are another reason. Thick walls with a huge isolating potential, also take a lot of time to heat up. The Minigama hardly has mass to heat up. As an example; dug-out-sandbank-kilns take many days to fire, not necessarily because the pottery needs it, but it’s the time needed to heat up the surrounding sand to high enough temperatures.

So the flames themselves are hot enough, it’s all about incapsulating them, but thick incapsulation also needs to be heated. read more about flame temperatures on Wikipedia:

https://en.wikipedia.org/wiki/Flame

I’m convinced it’s possible to mix together a Fireclay for the Minigama that handles the heat and doesn’t crack up. Here I try to find the right refractory materials mix and to make a Fireclay for the Minigama:

https://www.woodfireceramic.com/how-to-make-fireclay/

The pipe – traditionally makes the draft. As this picture shows, a 14 cm high pipe, with a 6 cm inside diameter, makes enough draft to “vacuum” in flames, making them 2 – 3 times higher out from the pipe to the right, than from the opening to the left. Both openings have the same diameter.

Even a short pipe make good draft

Different Minigama movie clips I found on YouTube:

Links on the Internet:

https://elenorwilson.blogspot.com/2013/07/small-japanese-kiln-sequel.html

CMU 442 Kiln Construction Jake Allee: Project 1 (alleekilnclass.blogspot.com)