Tall, Dark, and Mysterious

7/15/2004

Raku fire

File under: 1000 Words, I Made It Out Of Clay. Posted by Moebius Stripper at 6:11 pm.

Most of my pottery is fired in an electric kiln, which is easy to maintain and operate, but doesn’t lend itself to very bright or metallic colours. In a raku fire, the pots are left to burn in a sealed metal container, and the fire must leach oxygen from the glazes in order to burn. The results are varied:

A smoked effect, obtained by painting a pencil holder with a thin layer of iron oxide and firing it in the raku kiln.

Some other oxides - alas, I forget which - and oil on red clay.

White crackle glaze over B-Mix clay (which is magical - it’s got all of the good characteristics of porcelain - its colour, its texture - but with considerably greater structural integrity. It’s the only clay I’ve ever been able to make tall vases with) and trailed with oil. The unglazed bottom of the vase turned black. This vase also cracked in the raku fire, which is more stressful than the traditional cone 6 oxidation fire, but happily it cracked cleanly into two large pieces which I sealed together with Shoe Goo - the crack looks like a deliberate part of the crackle pattern.

5 Comments

  1. Wow! I think the last one is particularly stunning.

    What is the effect of the oil?

    (BTW, nice site.)

    - Sam — 7/15/2004 @ 7:50 pm

  2. Heh. I thought all the cracks were the glazing crackles.

    - meep — 7/16/2004 @ 1:29 am

  3. Hey, Sam -

    I don’t know the chemistry behind the oil, but on the white crackle, it gives the bright red, while alone, I think it’s the goldish colour on the middle vase, but I don’t remember. (Also, raku glazes vary considerably from firing to firing.)

    - Moebius Stripper — 7/16/2004 @ 6:02 am

  4. Wow! Another mathematician doing raku? Go figure. I love it. Wish I could see your pics (none are showing - I’ll check back later).

    I have always prefered pit kilns myself. Once saw a 50′ climbing pit kiln in Riegger’s beautiful book on Raku when I was in high school. Breakage is why we make kiln offerings - you are, aren’t you - a simple “kiln god” will usually do. ;)

    Have built many pit kilns since then (and one two venturi burner cantilvered arch brick kiln once). Don’t get the time for it that I used to though. Raku seems as rare as a sygygy or a quaterniaon for me these days. Nice to run into your post.

    25 years later, Amazon came along and it only took a few months to locate a copy.

    I’m moving in two days to a property better suited for Raku work. Can’t wait.

    - Markus Sandy — 6/15/2005 @ 3:05 pm

  5. Wow, another MS who does math and pottery! Cool.

    The pictures are back - don’t know what happened there. Alas, I haven’t had a chance to do much pottery at all this year - hopefully I’ll be able to move back close to my old (wonderful, wonderful) studio, or get a permanent place where I can set up a wheel. I only did raku that once, and with a lot of help, but it seems like the easiest and cheapest method of firing stuff on your own. Might look into it more at some point in the near future.

    - Moebius Stripper — 6/15/2005 @ 4:11 pm

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