Jim West on fri 27 nov 98
I ve got a question concerning the preparation of local clay for throwing.
I dug some clay from my property and made a bowl that turned out pretty
good. Preparing this clay was quite a chore. As dug it is too dry to throw.
I used a putty knife to smear it then add a little water. It takes a lot
of smearing to get enough to throw a pot. I ve been trying to find a good
way to get larger quantities of this clay into a throwable consistency.
My first attempt was break the clay into fist size chunks and soak it in
water. I let it set for several months and it made very little difference.
My most recent attempt was to use a cheese grater to shred the moist clay
into a 5 gallon bucket of water and then use a paint mixer to create a
slurry. I used about 1/3 clay and 2/3 water. This worked real well. The
result was a very uniform creamy liquid with only fine grit in suspension.
The plan was to let this set, siphon the liquid off the top, and then dry
the result to a throwable consistency.
But here is the problem. The stuff is not really settling out. I get about
1/16th inch of clear liquid per day on top which I siphon off. The slurry
is still pretty homogenous. A sample of the top 1/2 had larger gritty
particles in it. On the top, I can see a very fine cracking of the
solids. Almost like the clay is in swirling vertical sheets with clear
water between.
So the question is; is there anything I can do to get the solids to settle
out so that I have a reasonable consistency to start drying it. Right now I
have 10 gallons of this stuff and don t really have the facilities to dry
that quantity.
Any help would be greatly appreciated. And have a great Thanksgiving!
Jim West
June Perry on sat 28 nov 98
Dear Jim:
You need to let your dug clay dry completely. Then break it up into little
chunks and cover it with water to slake. It should do take very little time
for the bone dry clay to absorb the water.
Covering leather hard clay with water doesn't work very well; but bone dry
clay will very quickly absorb water.
What I've done it strain the slaked clay through some coarse mesh screening to
remove any large foreign matter and then run it through a finer screen after
that. Then you can just let it dry out naturally, or if you're in a hurry you
can let it settle and siphon off the water and dry the thicker slip on plaster
bats or specially made plaster tubs or any other method that you think will
work. Some people just put the clay in old pillow cases (purchased very
cheaply at Good Will Stores) and hang those up and let the slip drain and firm
up into a workable mass.
Enjoy!
Regards,
June
Joanne Van Bezooyen on sat 28 nov 98
I tried this once myself and used a screen to sieve it through to remove sand.
That took care of the solids, but mine needed other 'stuff' to be workable the
way I wanted it to be.
Joanne
Jim West wrote:
> ----------------------------Original message----------------------------
> I ve got a question concerning the preparation of local clay for throwing.
> I dug some clay from my property and made a bowl that turned out pretty
> good. Preparing this clay was quite a chore. As dug it is too dry to throw.
> I used a putty knife to smear it then add a little water. It takes a lot
> of smearing to get enough to throw a pot. I ve been trying to find a good
> way to get larger quantities of this clay into a throwable consistency.
>
> My first attempt was break the clay into fist size chunks and soak it in
> water. I let it set for several months and it made very little difference.
>
> My most recent attempt was to use a cheese grater to shred the moist clay
> into a 5 gallon bucket of water and then use a paint mixer to create a
> slurry. I used about 1/3 clay and 2/3 water. This worked real well. The
> result was a very uniform creamy liquid with only fine grit in suspension.
> The plan was to let this set, siphon the liquid off the top, and then dry
> the result to a throwable consistency.
>
> But here is the problem. The stuff is not really settling out. I get about
> 1/16th inch of clear liquid per day on top which I siphon off. The slurry
> is still pretty homogenous. A sample of the top 1/2 had larger gritty
> particles in it. On the top, I can see a very fine cracking of the
> solids. Almost like the clay is in swirling vertical sheets with clear
> water between.
>
> So the question is; is there anything I can do to get the solids to settle
> out so that I have a reasonable consistency to start drying it. Right now I
> have 10 gallons of this stuff and don t really have the facilities to dry
> that quantity.
>
> Any help would be greatly appreciated. And have a great Thanksgiving!
>
> Jim West
The Brinks on sat 28 nov 98
At 10:20 AM 11/27/98 EST, you wrote:
>----------------------------Original message----------------------------
>I ve got a question concerning the preparation of local clay for throwing.
>I dug some clay from my property and made a bowl that turned out pretty
>good. Preparing this clay was quite a chore. As dug it is too dry to throw.
>I used a putty knife to smear it then add a little water. It takes a lot
>of smearing to get enough to throw a pot. I ve been trying to find a good
>way to get larger quantities of this clay into a throwable consistency.
>
>My first attempt was break the clay into fist size chunks and soak it in
>water. I let it set for several months and it made very little difference.
The main first point is: don't try to do ANYTHING with the clay while it's
wet...get it totally BONE dry first, then add water to it in a bucket. I
also do about 1/3 clay and fill it almost to the top with water. After a
few days you should be able to reach in and stir the chunks into smaller
ones. With my clay, I let it sit a few more days and can pour off quite a
bit of water. I hope your clay will respond better if you start with dry
clay. If not, I would try making your slurry a lot thinner (more water) .
If the mixture is too thick, the grit will be held in suspension even if it
is heavier than the clay. Good luck; it WOULD be wonderful if you could
use clay from your own property. I don't know if your sample pot was of
any size; as you go larger you may find you have to add other clays to
prevent cracking while drying. I have to add grog to my river clay, but
your clay may already having something in it, like fine grit. Good luck.
Ann Brink
I
>
>
>
>
>
>
e-mail billann@impulse.net
Karen Gringhuis on sat 28 nov 98
Jim - I don't know about getting any grit out. I blunge my recycle
(Or new that's too dry) porcelain clay to pudding consistency, then
spoon off what water I can after it sits a few days. I even blot up
water w/ paper towels or newspaper. Then I scoop it out onto any
kind of plaster bat to dry to wetter-than-working-consistency.
Then ball it up and bad it to be mixed w/ virgin clay when I
wedge. I've been told that my success is because I have a fairly
LOW percentage of clay in my body. (Wish the same could be said of
fat in my corporeal body!) I try to dry the bats overnight and just
keep at it every day. Good Luck, Karen Gringhuis
P.S.
You deserve a prize for even trying this! Did you check Michael
Cardew's book for instructions - or the book by Harry (?) Davis?
I think it's called The Potter's Alternative?
Vince Pitelka on mon 30 nov 98
>But here is the problem. The stuff is not really settling out. I get about
>1/16th inch of clear liquid per day on top which I siphon off. The slurry
>is still pretty homogenous. A sample of the top 1/2 had larger gritty
>particles in it. On the top, I can see a very fine cracking of the
>solids. Almost like the clay is in swirling vertical sheets with clear
>water between.
Jim -
Your method (shaving with a cheese grater) seems pretty labor intensive.
The standard approach I have used for processing local clays is to let them
get absolutely bone-dry, and then completely immerse them in water. They
always slake down to a slurry overnight. After 24 hours I decant off the
extra water on top, and then mix thoroughly with a drill-mounted
jiffy-mixer. Finally, I work the slurry through window screen to remove
large particles and contaminants. This still leaves some fairly coarse
particles, but for my needs this hasn't been a problem. If you do not want
the coarse particles, you may have to work through several steps of
screening, using a finer screen each time. If you contact a wire supply
place like Western Wire in Portland, OR, you can order brass or stainless
screen in any mesh you want and make your own screen frames.
To salvage the barrel of slurry you have on hand, I would flocculate the mix
by adding some epsom salts. I think that your deposit of clay may
naturally be alkaline, due to the slow dissolution of soluble fluxes, which
makes it behave as if deflocculated. This will lessen the plasticity in a
clay, and will keep the particles in suspension in a slip or slurry. To
flocculate the slurry, take a pint or so of very hot water, and add epsom
salts, mixing with a hand blender, until no more will dissolve into
solution. Add this solution to your slurry a tablespoon at a time, mixing
thoroughly with the drill-mixer, until the slurry seems to thicken up
noticeably. At that time it may be thick enough to spread on canvas or
plaster to stiffen it up. Or, if you leave it for a few days, you should be
able to skim even more water off the top.
Good luck -
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Pat Porter on thu 3 dec 98
Hi Jim:
Just some thoughts........
Have you tried a portable cement mixer, adding a little water at a time??
And for the sludge that you have now, a couple of solutions. 1) Roll up
newspapers and tape them. Set them in the sludge containers. This should
soak up the necessary water, then pour the sludge onto a plaster of paris
dish to soak up the remainder of the water. 2) Pour the slip through many
layers of cheesecloth to act like a sieve. Then turn the stuff out onto a
plaster of paris dish.
Hope that helps.
Pat Porter
kitties@pcisys.net
Aurora Colorado
-----Original Message-----
From: Jim West
To: CLAYART@LSV.UKY.EDU
Date: Friday, November 27, 1998 8:20 AM
Subject: Need help w/local clay
----------------------------Original message----------------------------
I ve got a question concerning the preparation of local clay for throwing.
I dug some clay from my property and made a bowl that turned out pretty
good. Preparing this clay was quite a chore. As dug it is too dry to throw.
I used a putty knife to smear it then add a little water. It takes a lot
of smearing to get enough to throw a pot. I ve been trying to find a good
way to get larger quantities of this clay into a throwable consistency.
My first attempt was break the clay into fist size chunks and soak it in
water. I let it set for several months and it made very little difference.
My most recent attempt was to use a cheese grater to shred the moist clay
into a 5 gallon bucket of water and then use a paint mixer to create a
slurry. I used about 1/3 clay and 2/3 water. This worked real well. The
result was a very uniform creamy liquid with only fine grit in suspension.
The plan was to let this set, siphon the liquid off the top, and then dry
the result to a throwable consistency.
But here is the problem. The stuff is not really settling out. I get about
1/16th inch of clear liquid per day on top which I siphon off. The slurry
is still pretty homogenous. A sample of the top 1/2 had larger gritty
particles in it. On the top, I can see a very fine cracking of the
solids. Almost like the clay is in swirling vertical sheets with clear
water between.
So the question is; is there anything I can do to get the solids to settle
out so that I have a reasonable consistency to start drying it. Right now I
have 10 gallons of this stuff and don t really have the facilities to dry
that quantity.
Any help would be greatly appreciated. And have a great Thanksgiving!
Jim West
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