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olsen fast-fire kiln

updated sat 26 feb 00


Joan L. and James D. Warren on fri 25 feb 00


I built the Olsen fast-fire fifteen years ago, and it's still going strong.
It's a great kiln. BUT, not if you intend to bisque in it, or if you plan
to go for natural ash glazes from the fly ash in the kiln. You need at least
a 24 to 36 hr firing time for the ash to build up on your pots and get that
thick ash melt. I glaze my pots, and rely on the ash to enhance the glaze
ie: a beautiful wood-ash lustre . You can also get good copper reds, and
good blushes on your clay body . (Even more if you spray the unglazed
areas with ash water.) Any greenware I've put in has exploded because I
find it impossible to control the heat at that 900 degree F. quartz -
conversion period.

Except for the metal frame-work, I built it myself when I was almost 50.
I'm now in a new decade and still fire it by myself. I used the plan from
Olsen's first book and like you, drew out my own plan course by course and
color-coded the different bricks I would need.

I made some changes, which I'm glad I did. Things to increase its longevity.
I put soft brick on the floor of the kiln over the mullite shelving, then
increased the height of the chamber one brick width to compensate. I raised
the whole thing by building it on two courses of cement blocks, about 18
inches. I now have a low chair on wheels which I wheel back and forth
between fireboxes. Why I can still fire it! I used the Rhodes kiln idea of
insulation-- a layer of insulating board, then an outer layer of red brick.
(My husband did the red brick) This has made it a very permanent kiln, and
why it has lasted. I used 2300 bricks (better insulation), but think 2800
would be better. Even though the bricks have gone brittle, and shrunk some,
the arch is still tight BECAUSE once a year I soak kayo-fibre in kiln cement
and pack it between the arch bricks with a needle tool. This keeps it
So, yes you can reach cone 10 in 2 to 3 hrs, using about a quarter cord of
wood, but your pots will look like it. You'll reach cone melt, but not work
heat. Probably why a lot of people have given up on this kiln. I now fire
to cone 8 to 9 for about 6 to seven hours and use about 6 wheelbarrows of
wood. I use fir and cedar in 3 to 3 in width and ONE FOOT lengths placing
the pieces in the back of the firebox with raku tongues. A clean burn with
little smoke. My neighbors never know when I fire because there's only
smoke at start-up time and when I reduce. You may have a longer firing
using hardwood fruit wood but if you're young and strong that may not be a
bad idea. It takes practice to keep the temp up and control the burn. It's
a great kiln, once you know what it can do for you! I fire by sound, color
and cones-- chucked the parometer because it gave me false readings.

Hope this is of help. Joan Warren
Island B.C. Canada