Lee Love on sun 4 apr 10
All
If you do not have experience with natural clay, but only refined
industrial clay, it is understandable that you might not understand
the Thixotropic nature of some of them. It is related to soluble
organics in them.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Edouard Bastarache on sun 4 apr 10
All
Good observation Lee,
a boarding school in Nicolet, Quebec, 60 miles
from here and the surroundings went into the
Nicolet River decades ago; the Govt engineers
explained to us that the broken sewage system
produced humic acid which rendered the underlying
clay liquid, and zoom into the river.
They called the phenomenon "thixotropy".
It was presented on our science TV channel,
"Canal D"
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://edouardbastarache.blogspot.com/
http://www.flickr.com/photos/30058682@N00/
http://cerampeintures.blogspot.com/
http://albertpaintings.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://edouardbastarache.blogspot.com/
http://www.flickr.com/photos/30058682@N00/
http://cerampeintures.blogspot.com/
http://albertpaintings.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
----- Original Message -----
From: "Lee Love"
To: "David Woof"
Cc:
Sent: Sunday, April 04, 2010 11:18 AM
Subject: Re: Thixotropic clay? smash bag on floor etc. James, Ivor, Vince,
All
If you do not have experience with natural clay, but only refined
industrial clay, it is understandable that you might not understand
the Thixotropic nature of some of them. It is related to soluble
organics in them.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=94 --Rumi
Lee Love on sun 4 apr 10
All
From an old 1998 post:
Sheilah Bliss on mon 14 dec 98
Hi Ken -
Pulled out my old "Ceramics-A Potters Handbook -- 5th Edition by
Glenn C. Nelson, and found the thixotropic formulae. Fascinating
stuff! I've been telling myself for a huge time now that I'm gonna
make some of this.... wish I'd take myself seriously.
Apparently, Carol Jeanne Abraham gets credit for discovering it by
doing some "experiments in the particle suspensions of various clay
bodies" and came upon thixotropic clay. Thixotropy is "the property
exhibited by some gels of becoming fluid when shaken or stirred and
setting again to a gel when allowed to stand. In a clay body this
means that the clay becomes fluid when
manipulated, then sets up again when the motion is stopped." The
pictures of this stuff look really intriguing. You don't even work it
like "regular"clay.
Listed are both Cone 5 and Cone 9 clay bodies:
^5 ^9 '
25 25 Kentucky Ball Clay
15 15 Spodumene
15 15 Kona F-4
15 15 Kaolin (EPK)
10 25 Flint (silica)
20 5 Ferro Frit #3110
Also listed is a glaze for thixotropic clay body:
(Cone 5, crazes at Cone 9)
16 Kaolin (EPK)
24 Nepheline Cyenite
60 Fetto Frit #3124
The book explains how to manipulate the clay - kind of pulling and
shaking it at the same time - with pictures. Probably a good idea
to get the book. ( I found a copy at a used book store....) If
you get around to creating this stuff and working with it, hope you
let us know how it turns out. I'd love to hear about it!
Sheilah
Bliss Pottery
BlissPots @ aol.com
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Eva Gallagher on sun 4 apr 10
All
I've also seen that in local clays. Years ago I dug up some local clay that
came in red and gray layers about 1/4 inch thick. It was very short and
would crack until it was wedged and the layers disappeared.
However if the clay was left lying around the layers would start
reappearing - after a year it would be not exactly back to the original
layers but you could see them starting again. The clay would solidify again
as well. I guess because of these other forces at work that Neon-cat talked
about. Very interesting discussion.
Eva Gallagher
Deep River, Ontario
http://newfoundoutpotter.blogspot.com/
http://www.valleyartisans.com/gallagher/Gallagher.htm
----- Original Message -----
From: "Lee Love"
To:
Sent: Sunday, April 04, 2010 11:18 AM
Subject: Re: Thixotropic clay? smash bag on floor etc. James, Ivor, Vince,
All
If you do not have experience with natural clay, but only refined
industrial clay, it is understandable that you might not understand
the Thixotropic nature of some of them. It is related to soluble
organics in them.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=94 --Rumi
Maggie Furtak on tue 6 apr 10
All
Maybe I missed it, but was there any discussion of what happens with sand a=
=3D
t the tide line? =3DA0Seems like a related phenomenon to me and as far as I=
k=3D
now the key ingredients there are fine particles of sand and salt water. =
=3D
=3DA0
There's that point at the beach where the sand is perfect for dribble castl=
=3D
es. =3DA0If you slap the sand there repeatedly with your hand it miraculous=
ly=3D
ceases to be solid and becomes a thick soup. =3DA0Insert your hand into th=
e =3D
soup of sand and wiggle it around. =3DA0Stays nice and soupy. =3DA0The mome=
nt y=3D
ou try to pull your hand out, however the sand is miraculously solid again,=
=3D
trapping your hand like a chinese finger trap. =3DA0Quicksand!! =3DA0Enter=
tain=3D
s small children for hours. =3DA0
Does this mean this effect is to do with particle size and the proportion o=
=3D
f water present? =3DA0Is this even remotely the same thing that we see with=
c=3D
lay? =3DA0
-Maggie=3DA0=3D0A=3D0A=3D0A
Lee Love on wed 7 apr 10
All
Not all natural clays are Thixotropic. Mashiko clay is mined from
between bands of yellow sand, is very sandy and is not Thixotropic.
Ko-shigaraki, on the other hand, is. And Ko-shigaraki throwing waters
stinks to high heaven in the summer.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
ivor & olive lewis on thu 8 apr 10
All
Dear Lee Love
Without an analysis of the Mineral content of a clay and swabbing and
culturing to reveal and identify biological or organic contamination we
remain ignorant of facts relating to the causes of both Thixotropy and the
rich aromas associated with some wet clays.
Ralph E. Grim, in "Applied Clay Mineralogy"(1962) presents evidence and
discusses Thixotropy. On the question of Organic substances he seems to be
uncertain suggesting they may cause the clay to become hydrophobic or
hydrophilic. Informative reading If you are interested in these topics.
Regards,
Ivor Lewis,
Redhill,
South Australia
Lee Love on fri 9 apr 10
All
Ivor,
Shigaraki clay is finer than Mashiko clay. So, particle shape/size
might be a factor.
I have only experienced thixotrophy in organic, unrefined
clays. That have solubles and organics present that are removed from
industrially refined clays. Living clay vs. "killed clays." I am
not so interested in the explanation of why it happens as I am in the
superior qualities of potter specific clays compared to industrial
ones.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
douglas fur on fri 9 apr 10
All
Ivor
My recollection was that thixotropy was more related to the ammount and
particle shape of the silt portion. Is this how Ralph E. Grim, in "Applied
Clay Mineralogy' see's it? The article I read had dramatic pictures of
slides from Norway. Around here the common blue clay heads down hill after
heavy rains and vibrations from a small earthquake or just traffic. Often
someone will have built a house on top of the hill for the view and their
excavations will inject run-off into the clay. Then when their house takes
off the run around blaming anyone else.
DRB
Burien
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