mft like kiln

updated mon 14 mar 05

Pfeiffer, Dan R (Dan) on wed 9 mar 05

I saw a pic of a MFT like kiln , from the very little you could see in the
pic, that looked like it used folded kaowool to make the roof of the kiln.
My guess is they put long pins through the folds to hold the kaowool up.
This looks like this would be a very light roof and could make building easy
and not need to put steel straps to hole the sides in as I would think the
roof pins just sit on the walls. Anyone familiar with this type kiln? Is it
cheaper to use brick or fiber? good points and bad?

Dan & Laurel in Elkmont Al

Jim Larkin on sat 12 mar 05

Dan and Laurel from Elkmont say:
the=20=20
pic, that looked like it used folded kaowool to make the roof of the kiln.
=20=20
My guess is they put long pins through the folds to hold the kaowool up.=20=
=20
This looks like this would be a very light roof and could make building
easy=20=20
and not need to put steel straps to hole the sides in as I would think the
=20=20
roof pins just sit on the walls. Anyone familiar with this type kiln? Is
it=20=20
cheaper to use brick or fiber? good points and bad?=20=20
=20
Dan & Laurel in Elkmont Al >
Dan and Laurel,
I haven't seen an answer to this, so I'll wade in:=20
The folded kaowool modules you saw were probably Z-Block modules made by
Thermal Ceramics. I seriously doubt they were just folded kaowool with
long pins run through. Although the Z Blocs will work, Thermal Ceramics
manufactures a better fiber module (in my opinion) called Pyro-Bloc
modules. They come in 12" X 12 " squares, with whatever thickness you
want. They are a more dense product than the Z-Blocks. The Pyroblocs have
a stainless steel rod through the center of the module with an eyebolt
tee coming out the backside. You can order the end of the tee threaded,
or unthreaded and weld the end to an outside metal skin. I've used the
threaded type by welding a heavy expanded metal inside the frame of the
kiln, with angle iron bracing strips horizontally welded across the
outside frame of the kiln to help rigidze the expanded metal. The module
is then pushed into place with the threaded tee extending through the
expanded metal to the outside, and a washer and a nut put on to bolt the
pyrobloc module in place, then the next module is placed in beside the
first, compressed into place and bolted, and so on until you have "tiled"
the space.=20
The trick is to really compact the module into place by pushing it in hard
from two sides with a couple of metal plates the same dimension as the
sides of the module. You also alternate the "grain" of the modules. If
you don't really compress the modules into place very firmly, you'll have
shrinkage gaps between your modules after firing. (You'll still have
some, but not enough to be a problem.)
This will work well for a roof, or an entire kiln, using a soft brick
floor.=20
Is this style building worth it? Depends on your welding skills (to build
a good, square and plumb freestanding frame), and your tolerance for
working with fiber.It isn't a cheap way to work. The kiln I built in '99
with these modules has about 25 cubic feet of firing space and used 98
modules 5" thick for the walls, door and roof, at a cost for the modules
alone of $22.00 per module. It has held up very well with many, many
firings, and it does not cool too fast, as some folks say fiber kilns
will. If you do something like this for a roof, spray the inside and out
with itc or some other sealer to keep fibers from powdering.
As far as just folding fiber and running long pins through the folds to
sit on the walls, it sounds like a recipe for disaster. Don't do it.
Hope this helps,
Jim
=20
Jim Larkin=20
Fox Pass Pottery=20
Hot Springs, Arkansas=20
71901=20
foxpass@aristotle.net=20
www.foxpasspottery.com=20