fireblaze on thu 25 may 06
I have been reading clayart for at least two years now. I often go to
the archives to research problems and find great answers. However,
after many months of trying different clays, I now concede and hope that
someone on clayart can help me with a workable solution.
I live in the Pacific Northwest.in a rather humid area. I fire my
pottery several different ways and my current problem is with my
horsehair pieces. I need a clay that will withstand the shock of the
temperature change, will accept terrasig and produce a nice surface, and
one that has enough tooth to allow me to make pieces that are medium
sized. I have tried several different cone 10 clays from my local
suppliers with results that are not, in my opinion, satisfactory. Here
is what I have found:
Clays without sand or grog have had a high loss rate to cracking. Clays
with sand seem to have an orange peel surface (which greatly decreases
the appeal of the surface) after the bisque and I have experienced pop
outs with white dots on at least one of the clays. I have tried two
different Raku Clays with grog which look great right out of the bisque
but within a few days have pop outs with black dots. This is a problem
on Raku fired pieces with areas that have no glaze also.
I researched the archives and the answers I found were to slake the clay
and sieve to about 35 mesh. This isn't a workable solution for me since
I don't have a pugmill and I have arthritis. There is obviously nothing
I can do about the humidity here. I store the pieces in my house
instead of the studio, the pop outs just take longer to appear. I have
talked to local clay suppliers, tried various clays, and have still not
found a clay that will work. The other day I saw that one of my pieces
in a gallery, which had looked great when I took it to the gallery, now
had several pops on the surface. Can anyone recommend a clay that is
available in my area that will work under these conditions or offer a
workable solution?
Many thanks in advance,
Wanda Garrity
Fireblaze Pottery
Port Orchard, WA
www.fireblazepottery.com
fireblaze on fri 26 may 06
Gene & Latonna,
I use the same terrasig on my tinfoil saggar pieces, where I use a
porcelain clay body, and I don't have any problems with pop outs on
them. So why not use this clay for my horsehair pieces? Unfortunately,
when I have tried to use it I have had about 75% breakage.
Wanda Garrity
Gene & Latonna wrote:
"The pop out may be coming from the terra sig rather than the clay. I
have
not had a problem with pop wuts so I don't know for sure."
Snail Scott on fri 26 may 06
At 02:33 PM 5/25/2006 -0700, you wrote:
>...I have experienced pop
>outs with white dots on at least one of the clays. I have tried two
>different Raku Clays with grog which look great right out of the bisque
>but within a few days have pop outs...
That's a lot of lime pop for such a wide range
of clays. I don't believe I've ever had lime pop
from a commercially-made clay body unless it was
due to contact with plaster AFTER manufacturing,
i.e. used on an abraded plaster-topped wedging
table, damaged press mold, broken drywall edges,
etc.
Are you sure there's no source of loose plaster
bits in your studio?
-Snail
fireblaze on fri 26 may 06
Snail,
I don't have plaster or drywall (other than on the walls) in my studio
except for a couple of old plaster molds which I use infrequently for
slumping. All of my horsehair pieces are wheel thrown. My wedging
table is Formica countertop covered with canvas. Most of the time I use
the clay straight from the bag with just a little "slamming" on my
wedging table to soften and shape (again, with my arthritis, I can't do
a lot of wedging).
My studio is very humid (like most of the Pacific Northwest) and the pop
outs don't show up until the piece has been bisqued and then has been
sitting for awhile (either before or after the horsehair or raku
firing). I don't have a problem with pop outs with the grolleg
porcelain, the helmar porcelain, or the "B-mix" like clay that I use. I
use these three for other types of firing but they do not hold up to the
drastic temperature change of the horsehair process. Even with the care
I take in keeping the walls of my pots consistent and using a breeze
block in the process, I still get over 50% breakage when I use these
three for horsehair.
Wanda Garrity
Fireblaze Pottery
Port Orchard, WA
www.fireblazepottery.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Snail Scott
Sent: Friday, May 26, 2006 7:08 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: FW: Clay for Horsehair Firing
At 02:33 PM 5/25/2006 -0700, you wrote:
>...I have experienced pop
>outs with white dots on at least one of the clays. I have tried two
>different Raku Clays with grog which look great right out of the bisque
>but within a few days have pop outs...
That's a lot of lime pop for such a wide range
of clays. I don't believe I've ever had lime pop
from a commercially-made clay body unless it was
due to contact with plaster AFTER manufacturing,
i.e. used on an abraded plaster-topped wedging
table, damaged press mold, broken drywall edges,
etc.
Are you sure there's no source of loose plaster
bits in your studio?
-Snail
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Mud Duck Pottery on fri 26 may 06
Wanda
I use Phoenix clay from High Water for my horse hair with out any problems.
It throws well and can be fired to cone 10. Very snooth finish and takes
terra sig well.
The pop out may be coming from the terra sig rather than the clay. I have
not had a problem with pop wuts so I don't know for sure.
You can see my horse hair at our web site and these were made with Phoenix.
Hope this helps.
Gene & Latonna
mudduck@mudduckpottery.net
www.mudduckpottery.net
----- Original Message -----
From: "fireblaze"
To:
Sent: Thursday, May 25, 2006 5:33 PM
Subject: FW: Clay for Horsehair Firing
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