I think Lee briefly addressed this question for me a year ago but I'll
ask for more comments. anyway, I have built a small prototype of a
wood burning brick raku kiln. I have used hard fire brick for the fire
box and am going to build a brick firing chamber that I plan to line
with 1-inch 8-pound density fiber blanket. The chamber lid will also
be fiber lined. My gas fiber kilns fire great and last forever, so
far, without applying any coating to the fiber. Will the fiber hold up
with the wood ash? Any forseeable problems? What do you think? I have
provided a link to the fire box.
http://mudwerks.blogspot.com/2009/09/raku-kiln-fire-box.html Thanks.
Jeff
Coon Valley, WI
Ya Jeff, I have seen a guy on youtube spraying kiln wash on fiber blanket lining the arched top of a hinged lid on a kiln. However, with wood fuel I would recommend the hard brick be covered with the blanket and then a layer of IFB or red brick. The blanket insulates so well that when you open the kiln to remove the pots all the heat goes with and after reloading you start out with basically a cold kiln. With the hard brick liner you develop a heat sink that keeps the kiln warm while changing the load and needs less fuel to get going back up to heat again.
> From: Jeff Guin <mudhea...@hotmail.com>
> Subject: *WoodKiln* Wood Firing and Fiber
> To: "WoodKiln" <woodkiln@googlegroups.com>
> Date: Wednesday, September 16, 2009, 9:19 AM
> I think Lee briefly addressed this question for me a year
> ago but I'll
> ask for more comments. anyway, I have built a small
> prototype of a
> wood burning brick raku kiln. I have used hard fire brick
> for the fire
> box and am going to build a brick firing chamber that I
> plan to line
> with 1-inch 8-pound density fiber blanket. The chamber lid
> will also
> be fiber lined. My gas fiber kilns fire great and
> last forever, so
> far, without applying any coating to the fiber. Will the
> fiber hold up
> with the wood ash? Any forseeable problems? What do you
> think? I have
> provided a link to the fire box.
> http://mudwerks.blogspot.com/2009/09/raku-kiln-fire-box.html > Thanks.
> Jeff
> Coon Valley, WI
I am also about to venture into the wood fired fiber kiln arena,
however I have a boatload of 2ftx2ft and 1x2 kiln shelves available
and plan to line the inside of the 3x3x2 ft kiln with them and have
the fiber blanket and board between the shelves and a brick wall that
is there mostly for support..I have kept the Bourry firebox and
chimney from the train kiln we had, never really had good results
getting an even fireing in the train, even with sidestokeing...I am
unsure from my reading how much benift a single inch will provide
verses the surface deterioration of the blanket leading to debrie on
the pots..Niles Lou's book does not recomend backing fiber with hard
brick(reference from memory) but the book is pretty old relitive to
the advances in fiber....maybe you can tell us about the gas fiber
kilns you had and how they were put together..one advantage of the
kiln shelf lineing is the idea we could do salt at some time..warmest
regards, Mike Banyai Petoskey Michigan
So in Petoskey have you run into Jeff Cline? We usta fire in Kalamazoo.
This is the first I've heard of using kiln shelves for a the walls so it will be interesting to see how they handle the sharp changes it heat with the blasts of fresh stokes. I guess you must be using a cubeish chamber. Do you have any drawings?
I think one problem with the train being so uneven is the square shape does not simulate the shape of the large flame as it expands from the throat arch of the bourry box similar to the shape of early porcelain kilns in China. Another suspicion I have is most chimneys are not tapered to make a venture effect.
I don't know much of Nel's book but I read Frank Colson's "Kiln Building With Space-Age Materials" from which I decided on a 4½" hard firebrick, 1" fiber blanket ( I called Tim Fredricks about using board and wetting it like drywall so it would bend over the curved shape of the chamber and he said board was way too expensive per square foot), and 2½" of IFB. If you already have the board that's cool but I pretty much covered my chamber with a 100'x2'x1" roll. I needed about a 2'x4' area I had to fill in with scraps from mu old kiln and another barrel raku kiln Dart gave me but I covered it with some scraps left over. A hundred bucks of fiber goes a long way. You might be able to get cut off roll ends for a discount from Industrial Firebrick in Grand Rapids but a roll is easier to afford than I thought. However, I don't think it holds up with ash and salt bombardment so hard brick is the best choice for a liner.
I'll add that in a couple test warm-up fires in the Hobagama earlier in the year I took it to about 475° in fount and after letting it set it would cool down a bit and hold itself front to back within 50° and the chamber is 9' long. I now managed to load a third of the chamber and leave an unobstructed secondary stoke hole near the tail that will hold one 12"x1" stick of Maple onto a slab piece one at a time if I need to bump the temperature a little.
Give Jeff my regards if you run into him and stay in there eh!
> From: Micahel Banyai <mikeban...@gmail.com>
> Subject: *WoodKiln* Re: Wood Firing and Fiber
> To: "WoodKiln" <woodkiln@googlegroups.com>
> Date: Tuesday, September 22, 2009, 7:54 AM
> I am also about to venture into the wood fired fiber kiln
> arena,
> however I have a boatload of 2ftx2ft and 1x2 kiln shelves
> available
> and plan to line the inside of the 3x3x2 ft kiln with them
> and have
> the fiber blanket and board between the shelves and a brick
> wall that
> is there mostly for support..I have kept the Bourry firebox
> and
> chimney from the train kiln we had, never really had good
> results
> getting an even fireing in the train, even with
> sidestokeing...I am
> unsure from my reading how much benift a single inch will
> provide
> verses the surface deterioration of the blanket leading to
> debrie on
> the pots..Niles Lou's book does not recomend backing fiber
> with hard
> brick(reference from memory) but the book is pretty old
> relitive to
> the advances in fiber....maybe you can tell us about the
> gas fiber
> kilns you had and how they were put together..one advantage
> of the
> kiln shelf lineing is the idea we could do salt at some
> time..warmest
> regards, Mike Banyai Petoskey Michigan
i have a train and it has taken me awhile but i can get her "mostly" even. the keys for me have been the loading and how long i soak. i use both tumble stacking and shelves to push the flame around and the longer i soak the better. the shelves that act as a lid are covered by fiber and then a layer of ifb. i have had some problems when i unload in that the fiber doesn't want to release from the shelves. for the next firing i will cut the blanket to fit each shelf, with a small flap to overlap and use strips on top of that, then continue with the ifb layer. i wouldn't use it inside the chamber unless it was covered by something else to keep the dust and debris from flying around. i made the lower stoke/ash port of the bourry box a bit larger a few firings ago. i used a shredded paper/fireclay/sand/crushed ifb mixture troweled on to make a smoother openin and it has held up pretty well-few cracks. a little alumina added to it might help it as well. i would use it inside to fill in where bricks have chunked out and to round some of the corners in the exit wall.
T. E. Brown Each year nearly 5 MILLION healthy animals are euthanized in the US. Be a part of the solution. Spay and neuter your pets.
tb wrote: > the shelves that act as a lid are covered by fiber and then a layer of > ifb. i have had some problems when i unload in that the fiber doesn't > want to release from the shelves.
-- Des & Jan Howard Lue Pottery Lue NSW Australia 2850
I think that there is no reason not to put the firebrick first on the
shelve lid and then the fiber. The shelve lid gets to the temp of the
kiln, namely cone 12-14 depending on where you are, most all fiber
will not stand up to these temps, where as the soft brick will do
fine..The one fiber blanket that is rated for high temp is the
CeraCrome..it is however not one of the "safe" fibers and the dust is
truely not good for you. A better plan is to use the brick first and
then a safe , but lower temp range fiber on top of that, in my
opinion. I am useing the CeraCrome in my walls, but it is locked away
between the brick and the kiln shelf and does not need to be moved,
ever, I hope..I plan to get some pics up soon but have no drawings as
it was all in my head..and really does reflect the stuff we had used
as effectivly as I could figure out..the one thing that I did not
think of when I was building the train, was that one does not have to
limit the cross span to the width of a kiln shelf..this one will have
a width of three feet, still with a kiln shelf lid, but the mid part
will be supported but ware shelfs as part of the loading process, just
think of it as the top shelf, but no ware on it(grin)..the train or
cross draft is a grand design in my opinion,the Steve Harrison Burry
box is awesome.. but the with of only 18-20 inches limits good temp
difusion even with sidestokeing, which by the way I would replace with
a RAKU propane burner(feel free to throw bricks my way (grin)) I am
suspecious that the amount of BTU's introduced in side stokeing verses
the amount of cold air introduced is of dubious benifit..oh I know you
have do it and it is grand and it does raise the temp..but it does not
make as much sense as the propane, again in my opinion..you can still
get a lot of ash back there but the last boost to melt the ash is the
trick....we need to keep thinking of possible ways to do this that is
best for you..yea I know for some it is a fiancial question and for
others it is the ambiance of WOOD..but for some of us the idea of many
days is just time that can be used other ways..best possible is to be
able to pick what suites you..your mileage may vary..Mike Banyai
Petoskey Michigan
You can get some pretty thick commercial foil too.
-- Lee Love in Minneapolis http://mingeisota.blogspot.com/ "The intuitive mind is a sacred gift and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." -- Albert Einstein
If you look to the reference cited, the aluminum foil was used to good
effect on the top of the blanket between the blanket and steel cage to
contain the fiber particles off the top of the blanket..they then
mention they are going to put the foil on the shelf between the shelf
and the blanket..I plan to try this on the next fire as I would like
to see how this works..wonder if it will just vaporize at the 2400
Temp..one reference I found said that AL melts at 1220 F.. Mike Banyai
You ever burn a beer can in a campfire? Well the aluminum foil will
oxidize and turn into Al2O3 which melts at (drum roll please) cone 42!
In fact, cone 42 is composed of pure alumina, and is high as the cones
go.
> If you look to the reference cited, the aluminum foil was used to good
> effect on the top of the blanket between the blanket and steel cage to
> contain the fiber particles off the top of the blanket..they then
> mention they are going to put the foil on the shelf between the shelf
> and the blanket..I plan to try this on the next fire as I would like
> to see how this works..wonder if it will just vaporize at the 2400
> Temp..one reference I found said that AL melts at 1220 F.. Mike
> Banyai
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