Randy and Cara Randall on tue 16 mar 04
Hi! I joined this group hoping for some answers. I'm an extreme newbie in
any kind of clay venture. In a few years we'll be leaving my family's farm
to move to our own home, and I want to create some beads and/or pots from
clay found on the farm. We have 80 acres, and a stream runs through the
farm, and there is heavy clay soil. Can anyone give me some tips as to how
to proceed finding the clay, processing it, and then firing it in a wood
fire?ANY information or ideas would be greatly appreciated, as this is a
project very dear to my heart. This will be a way for me to remember my
native soil when I am far away. One day we know the farm will be sold, and
it will pass out of my family, so this is a method of keeping it with me.
Thanks,
Cara Randall
Logan Oplinger on wed 17 mar 04
On Tue, 16 Mar 2004 08:59:06 -0500, Randy and Cara Randall
wrote:
>Hi! I joined this group hoping for some answers. I'm an extreme newbie in
>any kind of clay venture. In a few years we'll be leaving my family's farm
>to move to our own home, and I want to create some beads and/or pots from
>clay found on the farm. We have 80 acres, and a stream runs through the
>farm, and there is heavy clay soil. Can anyone give me some tips as to how
>to proceed finding the clay, processing it, and then firing it in a wood
>fire?.....
>Thanks,
>Cara Randall
Hello Cara,
Welcome to Clayart! Your question has been asked several times over the
years on Clayart, and information and different ideas on how to prepare and
use local clay has been given in the answers. If you do a search in the
Clayart archives using the words "clay processing", you will get
66 "hits". Go to:
http://lsv.ceramics.org/scripts/wa.exe?S1=clayart
Type "clay processing" in the search dialog box and click on the search
button.
Good luck!
Logan Oplinger
Another Tropical Island
Randy and Cara Randall on thu 18 mar 04
I went looking for clay yesterday around the creek beds where the earth is
cut deeply. It was then that I realized I didn't know if I was looking at
clay or just mud. I grabbed up a sample of what looked "clay colored" and
brought it to my grandfather. He said that it wasn't clay, and that clay in
this region of Indiana is yellow! My grandmother said she thinks he's crazy,
and in the banks of their creek at her old home there were large chunks of
clay and it was grey in color. Grandpa then informed her that that was
"marl", not clay. Okay, wonderful. Now I'm completely confused! What is
marl? How do I tell if I am looking at clay. I have used clay in art
classes, but surely it isn't like just like that in its natural state, is
it?
Thanks for any help...
Cara
Bob Masta on sat 20 mar 04
Cara:
Marl is sediment with lots of lime in it. Definitely
not clay, since it isn't "plastic". If you can roll
your sample into a little coil and bend that around
to make a hoop, you've probably got clay. Also, when
clay dries it holds its shape well and has a certain
amount of strength; marl just gets really crumbly.
The clay you find should indeed be pretty much like what
you used in art classes, assuming you were using pottery
clay and not plasticine modelling clay. The color is
probably not a very good indicator, since it can change
greatly due to presence of organics or iron. And the
stuff you find may have some grit in it that you might
not have had in your classroom clay. That's not
necessarily a problem, and in fact may be helpful,
if there is not *too* much.
The main thing to watch out for is bits of lime
in the clay. This is definitely a Bad Thing, because
after firing they will expand when exposed to
moisture (even humidity in the air) and pop out
of the piece: the much-dreaded "lime pops". If there
is marl in your area, lime in the clay is a definite
possibility.
The usual references tell you to test for lime by
dropping bits of clay into a weak acid and to watch
for bubbling. This may be overly-strict, since you
will see bubbling from *any* lime, even lime that
is so fine that it will never be a problem. (Of course,
if it doesn't bubble you are all set.)
In my own case, I wanted to use clay from my garden
for purely sentimental reasons. And my clay is indeed
full of lime bits. If that turns out to be your case
as well, and you can't find lime-free clay, don't
give up. You can run the clay through a very fine
sieve (I used 80 mesh), and any lime that passes
through will be so fine it won't cause problems.
You'll want to wait until you have made your clay
into a smooth liquid slip before you do this.
It would of course be impractical for any production
potter to consider, but for small amounts like you
need the added labor is not a problem. The sieve
will also trap any other particles, including sand
that you might actually want as a filler, so you
may need to later add back some clean sand that
you are sure has no lime.
One other option that I experimented with is
milling the lime-laden clay in a ball mill until
the lime was so fine it wasn't a problem. However,
since I was milling the included sand as well, the
clay ended up very "short" and un-plastic due to
the added silica. I'm sure the vitrification
temperature must have gone way up as well, but as
it turned out this worked OK for press-molding
small knobs for drawer pulls, which were only
fired to cone 2. Not vitrified, but then neither
is a lot of low-fired earthenware.
As far as the basic processing, see the archives
as others have mentioned. The basic steps I use
are:
1) Let the clay dry *thorougly*.
2) Crumble and break the dry lumps and put through
a sieve made from an old aluminum window screen.
This is labor-intensive, and raises dust so you
should wear a respirator and/or work outdoors.
You'll be practically grinding the clay by
rubbing chunks against the sieve.
In my case this not only allowed removal of
pebbles and twigs, it created a product that
dissolved easily in the next step. Some folks
say you don't need to do this, that small
chunks will rehydrate on their own, but that
wasn't my experience.
3) Add the powdered clay to a large bucket of
water. There should be way more water than clay.
Mix thoroughly into a thin liquid.
4) Cover the bucket and let it sit for a few days.
5) Pour off the water from the surface. Let sit
a few more days and repeat as needed.
6) When it gets so it's not practical to pour off
any more water, you can dry it to working
thickness by pouring it onto plaster bats.
That's the standard way, which I used at first,
but it is really cumbersome and you must of
course have a big plaster bat. A better way
that someone on Clayart suggested is to pour
the semi-liquid into a sturdy cloth bag or the
leg of old jeans tied shut at the bottom. Hang
it somewhere to dry for a few days, and let Nature
do the work.
The only thing I haven't perfected yet is how to
remove the clay from the bag without a shower of
dry clay flakes from the sides of the bag falling
onto the moist clay... I have to pick them out or
cut off the outer layer of clay. (Anyone?) But
I still like this method way better than the plaster
bats method, which requires constant attention to
keep from over-drying the surface in contact with
the plaster. The bag method is nice and gradual
(though not as fast) and you can just poke the bag
every day to see if it is ready.
Hope this helps!
----ORIGINAL MESSAGE---------
From: Randy and Cara Randall
Subject: Re: Finding clay in Southern Indiana
I went looking for clay yesterday around the creek beds
where the earth is cut deeply. It was then that I realized I
didn't know if I was looking at clay or just mud. I grabbed
up a sample of what looked "clay colored" and brought it to
my grandfather. He said that it wasn't clay, and that clay
in this region of Indiana is yellow! My grandmother said she
thinks he's crazy, and in the banks of their creek at her
old home there were large chunks of clay and it was grey in
color. Grandpa then informed her that that was "marl", not
clay. Okay, wonderful. Now I'm completely confused! What is
marl? How do I tell if I am looking at clay. I have used
clay in art classes, but surely it isn't like just like that
in its natural state, is it?
Thanks for any help...
Cara
-----------------------------
Bob Masta
pots@daqarta.com
E.G. Yarnetsky on sun 21 mar 04
Hi !
There is also a blue-grey clay here. The blue is from an impure form
of iron, and when you fire this clay it turns brown. It is a low fire
clay and is quite abundant.
Darlene Y. Madison IN
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