Mark Duerr on wed 28 feb 01
Howdy. . .
I'd like to make some specialized high fire bricks
that will remain stable, heating and cooling repeatedly. I need
to make bricks of unconventional shape ruling out standard
fire brick. If anyone has experience in this type of brick
making and would be able to help me out with clay types, temp.
and grog it would be very much welcomed. If you would like
to respond off list, my e-mail address is:
Thanks in advance. . .
regards,
Mark Duerr
Mark Duerr on thu 1 mar 01
>If you get recipes off list rather than on, I would love a
>copy of them if you wouldn't mind.
>Margaret Forbe
Margaret,
So far I've seen one posting:
50% Fire Clay
50% Plaster Sand (Silica)
I built a neolithic updraft kiln last summer with
hard brick. I saw a design from 125 B.C.E. Rome that had
a removable top to get the pots in and out without a lot
of rebuilding. (The first "Weber") The kiln fired like a
dream for me but the weber top was pretty brittle and
cracked when I opened it up after cool down. My mix was:
50% Silica sand
20% Fire clay
20% red art clay
10% local earth clay
Straw and H20
I mixed it with my feet in a 300 gallon cattle tank.
After that experience I thought that it would be great
if I could find a clay body that stayed more like high fire
brick, thinking the early potters didn't really go and buy
all their brick, "you must be able to make it yourself?". My next
experiment was with the Raku body our clay supplier sells:
80% Stoneware clay (Cedar Heights)
20% Grog
That mix was made into 2"X15"X15" tiles. I let them (35)
dry out for 4 months in a low humidity setting and they looked
good going into the kiln. (no cracks) When they came out it
was a different story. Some were cracked 3"-4" in from the side.
I'd really like to understand the brick technology the
ancients used. When I was in college ('70-'77) I saw a film
about a workshop in the Sierras. The participants dug the clay,
made the brick, built a 6 chamber uphill downdraft kiln, made
pots from the natural clay and ground natural material
for glazing. . .
Does anyone have information about that workshop or remember the film?
Thanks,
mark
>Howdy. . .
>
> I'd like to make some specialized high fire bricks
>that will remain stable, heating and cooling repeatedly. I need
>to make bricks of unconventional shape ruling out standard
>fire brick. If anyone has experience in this type of brick
>making and would be able to help me out with clay types, temp.
>and grog it would be very much welcomed. If you would like
>to respond off list, my e-mail address is:
>
>
P.S. Responding to the list will help other interested potters.
Lili Krakowski on fri 2 mar 01
I fel liek a trained parrot. But again and once more. Look at Andrew
Holden's The Self Reliant Potter for brick making recipes.
out of Print try library.
Lili Krakowski
michael wendt on fri 2 mar 01
Brick making is very easy.
Make enough calcine to mix at least 60% calcined kaolin to 40% unfired
kaolin (or superduty fireclay if you can get it). Since I am at the source,
I use Helmer Kaolin (PCE ^ 32), but any high refractory clay with less than
2% free silica will work. Fire the calcine at least 2 cones hotter than you
plan to fire your products to reduce additional shrinkage during repeated
firings. DON'T add any sand as then you will have to contend with Quartz
inversion which is quite severe. You will find hand molding moist in oiled
metal forms to be fast and easy. Make the forms so that you can spring the
piece out when you finish shaping it.
Regards,
Michael Wendt wendtpot@lewiston.com
You wrote:
I'd like to make some specialized high fire bricks
that will remain stable, heating and cooling repeatedly. I need
to make bricks of unconventional shape ruling out standard
fire brick. If anyone has experience in this type of brick
making and would be able to help me out with clay types, temp.
and grog it would be very much welcomed. If you would like
to respond off list, my e-mail address is:
Michael Mandaville on sun 7 oct 01
On Thu, 1 Mar 2001 16:43:01 -0600, Mark Duerr
wrote:
>>If you get recipes off list rather than on, I would love a
>>copy of them if you wouldn't mind.
>
>>Margaret Forbe
>
>
>
>Margaret,
>
> So far I've seen one posting:
>
> 50% Fire Clay
> 50% Plaster Sand (Silica)
>
> I built a neolithic updraft kiln last summer with
>hard brick. I saw a design from 125 B.C.E. Rome that had
>a removable top to get the pots in and out without a lot
>of rebuilding. (The first "Weber") The kiln fired like a
>dream for me but the weber top was pretty brittle and
>cracked when I opened it up after cool down. My mix was:
>
> 50% Silica sand
> 20% Fire clay
> 20% red art clay
> 10% local earth clay
> Straw and H20
>
> I mixed it with my feet in a 300 gallon cattle tank.
>
> After that experience I thought that it would be great
>if I could find a clay body that stayed more like high fire
>brick, thinking the early potters didn't really go and buy
>all their brick, "you must be able to make it yourself?". My next
>experiment was with the Raku body our clay supplier sells:
>
> 80% Stoneware clay (Cedar Heights)
> 20% Grog
>
> That mix was made into 2"X15"X15" tiles. I let them (35)
>dry out for 4 months in a low humidity setting and they looked
>good going into the kiln. (no cracks) When they came out it
>was a different story. Some were cracked 3"-4" in from the side.
>
> I'd really like to understand the brick technology the
>ancients used. When I was in college ('70-'77) I saw a film
>about a workshop in the Sierras. The participants dug the clay,
>made the brick, built a 6 chamber uphill downdraft kiln, made
>pots from the natural clay and ground natural material
>for glazing. . .
>
>Does anyone have information about that workshop or remember the film?
>
>Thanks,
>
>mark
>
>
>>Howdy. . .
>>
>> I'd like to make some specialized high fire bricks
>>that will remain stable, heating and cooling repeatedly. I need
>>to make bricks of unconventional shape ruling out standard
>>fire brick. If anyone has experience in this type of brick
>>making and would be able to help me out with clay types, temp.
>>and grog it would be very much welcomed. If you would like
>>to respond off list, my e-mail address is:
>>
>>
>
>
>P.S. Responding to the list will help other interested potters.
Hello, Mark and Margaret. I'm glad that somebody else besides me is
interested in making their own firebricks.
From Conrad's "Formulas", it is possible to abstract the following
generalized formula for the making of hard firebrick:
grog: 40-80%
fireclay: 0-40%
ball clay: 10-20%
From this generalized formula you can decide for yourself just how much you
want to control cracking (by adding grog), bonding strength (fireclay), and
workability (ball clay).
Mark, I might should add that you are ahead of me at this game, since I
have not yet fired any brick. I have, however, been doing some "snooping
around" on the internet, and here are a couple of web sites which you might
find to be interesting:
http://www.shol.com/agita/thespiel.htm
and
http://www.gtz.de/basin/gate/brickclamps.htm
One of the interesting things which I have learned from the second site
above is that brickmakers sometimes mix their clay with coal in order to
fire their bricks from the inside out, as well as from the outside in. In
fact, if a person uses the formula for hard brick, but instead of grog uses
pulverized coal, the result would be the general formula for insulation
brick, which should fire more easily. Remember that insulation brick is
also used structurally, and that the air pockets which the coal leaves
behind prevent the heat loss which comes from thermal conductivity. In
fact, this is the kind of brick which I plan on making myself.
There are not a lot of people around who are making their own firebrick, so
_please keep in touch_!
Sincerely
Michael Mandaville
Austin, Texas
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