Lori Leary on thu 5 feb 04
Here's my question ....why use a pyrometer or cones at all for raku?
I've always have great results just by watching the kiln and glazes
closely.....Of course this works only for glossy glazes. For dry, matte
glazes you can either fire a glossy piece at the same time or you can
learn to approximate what temp the kiln is at by the color inside the
kiln. (orange, yellow-orange, yellow, ect.)
When firing a glossy glaze, there will usually be a period when the
glaze starts to melt and gets *really* ugly and bumpy. One has to
watch very closely after this....the glaze will begin to smooth
out....when it is almost done, I cut back the flame a bit and put the
kiln in light reduction by partially covering the exit flue. (no
need to have flames shooting out everywhere) This helps even out the
kiln temp and ensure an even glaze melt. I then "clear the kiln" (open
the damper) for a few minutes and pull the ware. CAUTION: If your
glazes goes 'ugly' for a second time, it's usually overfired and there
is not much you can do with it.
Our own Steve Branfman's book has an excellent description of this process.
All of the above info refers to firing an updraft, by the way.
I have to add this.....a raku kiln that takes 90 minutes to get to temp
is a BIG waster of time and energy. Refractory products are not THAT
expensive. Get rid of the old kiln and just build a new efficient
one. I know some may say they couldn't do that...no time, money,
skill..... Really, it's not that hard. I have built many raku kilns,
both fiber and brick and it's not difficult at all. And the energy and
time savings are well worth it.
Email me privately, if you have any questions,
Lori L.
...not firing much raku these days, but still does occasionally
Lori Leary on thu 5 feb 04
If you prefer a pyrometer, that's fine. But you would be amazed at just
how accurate one's judgement of kiln temp by color can be after a bit of
experience. A pyrometer is not neccesary, nor are cones. I would hate
for anyone to feel they can't raku because they don't have a pyrometer.
To be honest, I've seen more bad raku firing results from people
watching cones and a pyrometer rather than the pots. Knowing how to
monitor the status of a raku firing without a pyrometer or cones is a
handy skill. Knowledge and skill will never fail you once you have it.
(By the way, when I say "you" I mean it in the most general way...not
you personally, Susan.)
I have to say though, I don't agree with you about the overfiring. I've
never seen an overfired raku pot that looked like anything other than it
is....an overfired pot.
Lori L.
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