Vince Pitelka on tue 20 sep 05
> Does anyone have a good recepie for an insulating clay/cement coating
> for a wood fired kiln? One that will set hard, be durable in the outdoors
> of Minnesota (we have a covered shed but open side walls) will seal the
> kiln well and provide some insulating benefit. We have a 9" thick hard
> brick brick shell and need just an exterior coating material. In other
> words, no fiber blanket as we also want to provide some lateral structural
> support.
Joe -
I've used an inexpensive insulating mixture that would meet your needs.
This is a cold-face refractory, intended for insulation outside of the
primary hotface refractory layer. In a cement mixer, combine 20 pounds
Portland cement and 50 pounds fire clay (or any scrap claybody). Add water
until the mixture is quite liquid. Dump the mixer into a large tub or
stabilized wheelbarrow, and with a hoe, start blending coarse sawdust into
the mixture, and keep adding it in until you have a mixture that can be
packed into place by hand. If it helps, you can stretch a layer of chicken
wire over the kiln to hold this packed mixture in place as it cures. This
stuff will produce a lot of smoke during the first few firings as the
sawdust burns out, but that will taper off. After it stops smoking,
weathercoat the surface with a 50-50 mixture of portland cement and clay
blended to a slurry.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Joseph Passofaro on tue 20 sep 05
Does anyone have a good recepie for an insulating clay/cement coating
for a wood fired kiln? One that will set hard, be durable in the outdoors
of Minnesota (we have a covered shed but open side walls) will seal the
kiln well and provide some insulating benefit. We have a 9" thick hard
brick brick shell and need just an exterior coating material. In other
words, no fiber blanket as we also want to provide some lateral structural
support.
Thanks in advance,
Joe Passofaro
Paul Herman on tue 20 sep 05
Joseph,
We used a homemade mix for the shell of our wood kiln. It uses a
material called diatomacious earth, which I can get at the auto parts
stores in Reno. The product is called "Floor Dry", and is used to
soak up oil and grease from the garage floor. It comes in two grades,
fine and coarse (about 12 mesh and 6 mesh).
DE is a natural refractory material, composed of the skeletons of
tiny marine animals. It has a history of being used as a cheap high
temperature insulation.
The mix we used is this:
fine DE 2
coarse DE 2
clay 1
cement 1
Mix it sloppy, and trowel on. With a nine inch hard brick wall, I
would be inclined to lay it on thick, several inches.
good firings,
Paul Herman
Great Basin Pottery
Doyle, California US
greatbasinpottery.com
On Sep 19, 2005, at 9:03 PM, Joseph Passofaro wrote:
> Does anyone have a good recepie for an insulating clay/cement coating
> for a wood fired kiln? One that will set hard, be durable in the
> outdoors
> of Minnesota (we have a covered shed but open side walls) will seal
> the
> kiln well and provide some insulating benefit. We have a 9" thick
> hard
> brick brick shell and need just an exterior coating material. In other
> words, no fiber blanket as we also want to provide some lateral
> structural
> support.
>
> Thanks in advance,
>
> Joe Passofaro
>
Steve Mills on thu 22 sep 05
Another variant of this mix which we have used very successfully is to
substitute chopped straw for the sawdust; roughly chopped into 2 inch
lengths (its not critical), the straw helps to bind the mix onto the
Kiln wall while at the same time helping to reduce shrinkage cracking.
Adding a reasonable percentage of sand as well is also helpful in the
shrinkage stakes!
Steve
Bath
UK
In message , Vince Pitelka writes
>> Does anyone have a good recepie for an insulating clay/cement coating
>> for a wood fired kiln? One that will set hard, be durable in the outdo=
>ors
>
>Joe -
>I've used an inexpensive insulating mixture that would meet your needs.
>This is a cold-face refractory, intended for insulation outside of the
>primary hotface refractory layer. In a cement mixer, combine 20 pounds
>Portland cement and 50 pounds fire clay (or any scrap claybody). Add wat=
>er
>until the mixture is quite liquid. Dump the mixer into a large tub or
>stabilized wheelbarrow, and with a hoe, start blending coarse sawdust int=
>o
>the mixture, and keep adding it in until you have a mixture that can be
>packed into place by hand. If it helps, you can stretch a layer of chick=
>en
>wire over the kiln to hold this packed mixture in place as it cures. This
>stuff will produce a lot of smoke during the first few firings as the
>sawdust burns out, but that will taper off. After it stops smoking,
>weathercoat the surface with a 50-50 mixture of portland cement and clay
>blended to a slurry.
>- Vince
>
>Vince Pitelka
--
Steve Mills
Bath
UK
Lee Love on fri 23 sep 05
From: Steve Mills wrote:
>Another variant of this mix which we have used very successfully is to
>substitute chopped straw for the sawdust
They use nuka (rice husks) here. I got 3 bags of nuka ash ash today, from one of Jean's English students. I gave her a small dish as a thank you. Another student (our landlord's daughter) brought us freshly harvested rice as a gift from her family. "New" rice takes less water to cook. It is tender and has more flavor. These kinds of exchanges is why I wanted to live here.
Yesterday, another student gave us a bag of giant Japanese grapes (they are as big as plums back home.)
Hey, the teacup on ebay is going cheap! You can see it here:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=7713918126
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://seisokuro.blogspot.com/ My Photo Logs
"Our scientific power has outrun our spiritual power. We have guided missiles and misguided men.
--Martin Luther King Jr. (1929 - 1968)
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