Hank Murrow on tue 12 jan 10
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On Jan 12, 2010, at 1:24 PM, MacIntire, Matt wrote:
> I've always wondered... when people fire an anagama for 100 hours,
> does it
> necessarily take 100 hours to get to temperature? Or are people
> extending
> the firing deliberately, to get the desired ash build up?
>
> In other words, would it be possible to fire an anagama to a similar
> endpoint (cone 12 or whatever) in 30 hours? Obviously the results
> of a 100
> hour firing would be different from a 30 hour firing. I understand
> WHY
> people might want to fire for long periods.
Dear Matt;
Having fired several anagamas, I feel safe in saying that temperature
can be achieved in three days. However, EVEN temperature cannot be
had in such a time frame. It takes a long while for the floor and the
rear of these kilns to get up there, and 20_30% success in one of
these kilns would be counted as failure, IMHO.
Last May, we had a sort of 'good old days' firing at the Jewel Creek
anagama on the Oregon Coast, former U of Oregon ceramics majors and
former faculty, along with the regular crew from Portland. We had the
front up to Cone 10 in 28 hours, and the rest of the kiln followed
suit over the next 18 hours. We finished the firing @ 92 hours with
C14 down in front, C13 in the middle, and C10 at the very rear. A
lovely fire revealed itself at the end of a week's cooling. Lots of
ash buildup, and rich surfaces on all the clays. We only side stoked
on the last full day........... a relaxed and wonderful experience
indeed.
>
> What I am trying to understand is if it is actually necessary to
> fire for
> days, due to the nature of the kiln, or if that schedule comes from a
> deliberate decision to use the kiln in that way.
I have fired a Donovan catenary 'fast fire' for 30 hours, and while
it makes lovely surfaces, the shorter firing could never be mistaken
for the results from a long-fired anagama, IMHO.
I will be joining the 25th anniversary firing of the East Creek
anagama in March, and expect a calm and deliberate firing of 100+
hours....... can't wait to see what that kiln will give me again, as
I have not fired it for ten years or more.
In such firings, C10 and above for three or four days......., one has
to be mindful of cristobalite formation and adjust one's clays to
avoid it. My favorite Tea & Sake body is 1/3 ball, 1/3 kaolin, and
1/3 Kyanite...... no spar at all, and no silica either. Bulletproof
and pretty with lots of ash fall; and somewhat porous which is a Good
Thing for both uses.
Cheers, Hank
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Paul Herman on tue 12 jan 10
Hi Matt,
Good and interesting questions you are asking here, I'll take a stab
at some of them.
First off I'll state that time spent in the heat can have a profound
effect on the finished fired object. Think of how cones will melt at a
lower temperature if brought to up heat slowly, and melt at a higher
temperature if fired quickly. The reactions that take place in our
kilns require heat AND time to achieve, and neither operate in a
vacuum, by themselves. Heat and time go hand in hand. People
definitely extend the firing time to achieve desired effects.
We fire our anagama for about 72 hours usually, and have often talked
about making it a four day firing, but it hasn't happened yet. Some
potters I respect have intimated that if we ever did do a four day, we
would never want to go back. The very fine ash that glazes our work
would be more pronounced with another day. Firing the kiln is an
arduous process, and by the third day everyone is pretty tired. So you
can kinda see where we are stuck.
Svend Bayer said something like he could fire his big kiln in a day,
but the results were bland. Run it out for 3-4 days and you'll get
some good stuff, lots of fine ash glaze.
For our kiln, it just has evolved into the 72 hour firing cycle, as a
natural, slow and easy way to get that big pile of bricks hot enough.
I'm hoping to do a four day one of these times, but it won't happen
this spring.
good firings,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Jan 12, 2010, at 1:24 PM, MacIntire, Matt wrote:
> I've always wondered... when people fire an anagama for 100 hours,
> does it
> necessarily take 100 hours to get to temperature? Or are people
> extending
> the firing deliberately, to get the desired ash build up?
>
> In other words, would it be possible to fire an anagama to a similar
> endpoint (cone 12 or whatever) in 30 hours? Obviously the results
> of a 100
> hour firing would be different from a 30 hour firing. I understand
> WHY
> people might want to fire for long periods.
>
> What I am trying to understand is if it is actually necessary to
> fire for
> days, due to the nature of the kiln, or if that schedule comes from a
> deliberate decision to use the kiln in that way.
>
> Thanks in advance.
Nils Lou on tue 12 jan 10
We are loading the end of February for the 25th anniversary
celebration of the East Creek anagama. Back in 1985 while=3D20
Katsuyuki Sakazume was at Peter's Valley having built the
3rd Cent. replica anagama there he came to Oregon and laid out
the plans and foundation for an 8th Cent. replica of a Korean
anagama. Diane Lou is constructing a documentary book of the last=3D20
25 years covering 101 firings. Potters from twelve countries have
participated in that time. It is a lovely kiln, firing with ease
after gentle tweaking over the years. We use six cords of fir and
oak--sometimes alder. 100 hours is the usual fire time with a week
of cooling. For the last ten years or so Cindy Hoskisson has been
the fire master/organizer/boss. I still make a few pots for the=3D20
fire. Lately we fire 2-3 times a year. Any wishing to visit during the=3D20
celebration firing are welcome. Starts first Wednesday in March...
nils lou, professor of art
http://nilslou.blogspot.com
www.tinyurl.com/bpc5nm
503.883.2274
"Play is the essence of creativity", and
"What is not brought forward into consciousness....
we later call Fate", Carl Jung
MacIntire, Matt on tue 12 jan 10
I've always wondered... when people fire an anagama for 100 hours, does it
necessarily take 100 hours to get to temperature? Or are people extending
the firing deliberately, to get the desired ash build up?
In other words, would it be possible to fire an anagama to a similar
endpoint (cone 12 or whatever) in 30 hours? Obviously the results of a 100
hour firing would be different from a 30 hour firing. I understand WHY
people might want to fire for long periods.
What I am trying to understand is if it is actually necessary to fire for
days, due to the nature of the kiln, or if that schedule comes from a
deliberate decision to use the kiln in that way.
Thanks in advance.
Mike on wed 13 jan 10
Hello Matt,
Yes, it's absolutely possible, and you're also right about the time spent b=
uilding up ash. Potters fire with wood primarily here where I live. Mostly =
anagama and noborigama, and various permutations of somewhere between eithe=
r one. 40 hours would be considered a long firing, usually the number is cl=
oser to 30 or less. So I think that to answer your question, it's a delibe=
rate decision to fire the kiln a certain way for particular results.
One potter I know fires in about 5 hours, and he once fires. It blew me awa=
y when he told me, but the proof is in the pudding, as they say, and he has=
very nice pots. According to him, he cut the firing time by half when he s=
topped using hard fire brick in his kiln, half again when he stopped using =
shelves.
Keep in mind that I'm talking about people firing glazed ware, at least the=
vast majority. In a 'standard' anagama, 30 hours will get you some very dr=
y pots if you're doing unglazed ware.
That said, the glazed work coming out of the wood kiln is usually much more=
interesting (I'm talking about Karatsu style pottery here) because of the =
color and textural variation that is achieved in the clay and glaze surface=
s, even with a relatively short firing. That is why although I fire with ga=
s currently, I'm working hard on getting a wood kiln built.
Mike
in Taku, Japan
karatsupots.com
karatsupots.blogspot.com
karatsupots-workshop.blogspot.com/
-----------------------------
Date: Tue, 12 Jan 2010 16:24:53 -0500
From: "MacIntire, Matt"
Subject:
Re: east creek anagama
I've always wondered... when people fire an anagama for 100 hours, does it
necessarily take 100 hours to get to temperature? Or are people extending
the firing deliberately, to get the desired ash build up?
In other words, would it be possible to fire an anagama to a similar
endpoint (cone 12 or whatever) in 30 hours? Obviously the results of a 100
hour firing would be different from a 30 hour firing. I understand WHY
people might want to fire for long periods.
What I am trying to understand is if it is actually necessary to fire for
days, due to the nature of the kiln, or if that schedule comes from a
deliberate decision to use the kiln in that way.
>
MacIntire, Matt on wed 13 jan 10
Thank you to everyone who helped me understand how an anagama's protracted
firings work. I appreciate your helpful insights.
Even though I had suspected much of this, I'm glad to have a much better
understanding. It is always interesting to hear what people are doing.
so FWIW... I fire a two chamber noborigama style kiln that I built, (~60
ft3 total) which is a hybrid of a few different designs. Not at all a
traditional design. I mostly had insulating bricks available, so I used
them and coated them with ITC. Seems OK so far and it heats up fast and
cools down pretty slowly. The first chamber takes about 12 hours to fire,
the second fires off in 2-3. So I knew fast fire with wood was definitely
possible. Of course, we don't get much ash buildup. So we use glazes
rather liberally, especially shinos. What we get is more like super strong
flashing. What comes out is way more interesting than results from a
standard gas kiln, IMO.
We are putting small salt cups throughout the setting to enhance these
flashing effects. This has been working great for us. We get very strong
flashing and spot glazing throughout the kiln, even in what would otherwise
be "dry" spots away from the firebox. I like that it is very localized and
doesn't affect the whole pot. Being able to place the cups gives us a
degree of control over where the flashing happens, which I also like.
Since we are not purists, we've also experimented with blowing in ash. Thi=
s
seems promising, but mostly effects the pots right next to the firebox.
Next time I want to try much finer ash to see if it will disperse deeper
into the stack. I'm also tempted to add some goodies to the ash before we
blow it in. What the heck, right? I've met one guy who blows in GLAZE!
There are a lot of ways to get good results. I'm proud that I'm not a
purist.
Anyway, thanks again to everyone for their helpful responses. Keep busy ou=
t
there.
Craig Edwards on thu 14 jan 10
Hello Matt and all: You've already received excellent answers from some
qualified potters that I respect. Here are a few random thoughts.
I have found that there seems to be a natural pace that wood kilns fire at.
You can speed up the pace, but you will be at odds with the kiln. Exhaustin=
g
at best, disastrous more likely. Have a dialog with the kiln, it has a
reality of it's own, it will tell you what is natural and what is forced.
Try not to machine time into hours and minutes, Fire until the pots have
the effects that you are looking for, then stop. Very simple. My firing
used to last 5 days, the concern was layers and colours of ash. Now I'm mor=
e
concerned about the effects of long firings have on glazes, the firing last=
s
about 3 1/2 days. Some may achieve what they want in a shorter time. Are
long firings exhausting? Physically yes, mentally no... because I enjoy
them!
If you have some time to waste, there are pictures posted on my blog from
the last firing.
Enjoy woodfiring
--
Make Good Pots
~Craig
New London MN
http://woodfiredpottery.blogspot.com/
Kiln building workshop October 15-22
Taku, Japan
karatsupots-workshop.blogspot.com/
On Wed, Jan 13, 2010 at 10:53 AM, MacIntire, Matt wrote:
> Thank you to everyone who helped me understand how an anagama's protracte=
d
> firings work. I appreciate your helpful insights.
>
> Even though I had suspected much of this, I'm glad to have a much better
> understanding. It is always interesting to hear what people are doing.
>
>
> so FWIW... I fire a two chamber noborigama style kiln that I built, (~60
> ft3 total) which is a hybrid of a few different designs. Not at all a
> traditional design. I mostly had insulating bricks available, so I used
> them and coated them with ITC. Seems OK so far and it heats up fast and
> cools down pretty slowly. The first chamber takes about 12 hours to fire=
,
> the second fires off in 2-3. So I knew fast fire with wood was definitel=
y
> possible. Of course, we don't get much ash buildup. So we use glazes
> rather liberally, especially shinos. What we get is more like super stro=
ng
> flashing. What comes out is way more interesting than results from a
> standard gas kiln, IMO.
>
> We are putting small salt cups throughout the setting to enhance these
> flashing effects. This has been working great for us. We get very stron=
g
> flashing and spot glazing throughout the kiln, even in what would otherwi=
se
> be "dry" spots away from the firebox. I like that it is very localized a=
nd
> doesn't affect the whole pot. Being able to place the cups gives us a
> degree of control over where the flashing happens, which I also like.
>
> Since we are not purists, we've also experimented with blowing in ash.
> This
> seems promising, but mostly effects the pots right next to the firebox.
> Next time I want to try much finer ash to see if it will disperse deeper
> into the stack. I'm also tempted to add some goodies to the ash before w=
e
> blow it in. What the heck, right? I've met one guy who blows in GLAZE!
> There are a lot of ways to get good results. I'm proud that I'm not a
> purist.
>
> Anyway, thanks again to everyone for their helpful responses. Keep busy
> out
> there.
>
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