primalmommy@IVILLAGE.COM on mon 18 jun 01
I'm preparing to make my first batch of terra sig from redart clay, following Vince's recipe. I also have a big bucket of earthenware clay I dug at a lake (wolf lake) in michigan, very plastic, grey-green stuff that fires peach, and melts at high temps to a mustardy green; I'd like to make a small batch of sig from that, too. But it takes, I understand, a lot of clay to make a little sig, and the leftover clay is pretty much useless, once robbed of its smallest platelets.
So here's my question: can I use less clay by using only the finest particles of my wolf lake clay? When I first dug it, I mixed it to a thin slip and poured it through the strainer basket from an old washing machine to get rid of roots and chunks. It has dried into chunks, which I "grate" on a window screen into a bowl before adding water to make clay. What if I ran that dry material through a finer and finer mesh, until I had just "clay flour"? Would that put me ahead, at all, in the amount of terra sig that would hang in suspension in the beaker?
What I'm asking is, (and I apologise if this is a stupid question) -- is there a relationship between the number of "suspendible" platelets and the size of particles in dry clay?
Thanks in advance for any opinions...
Kelly Savino in Ohio
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Khaimraj Seepersad on tue 19 jun 01
Hello to All ,
Kelly ,
down here in the Tropics , we have quite a variety of sticky
surface clays . So I have taken to just collecting the earth
of our canefields.
Now , I just collect a few lumps and dry . Then re-wet , in a
quantity of water , pass through a -325 mesh sieve , thin
to a watery quality and apply to the body .
Polishing is when the object is dried , and has had a thin coat
of soybean cooking oil applied and allowed to soak in .
Cloth or plastic is used depending on what I want .
The cane seems to extract Calcium Oxide from the soil , so
these clays can be self grogged , easily fired to 1100 - 1130
deg.c and will stand , mature and make beautiful objects.
Bloating is at 1150 to 1180 deg.c .
Hope this helps .
Khaimraj
* Linda , Bret and Ivor , I owe you all sensible replies , presently
over loaded , but I will get to you .
Thanks for your patience in advance .
Khaimraj
-----Original Message-----
From: primalmommy@IVILLAGE.COM
To: CLAYART@LSV.CERAMICS.ORG
Date: 18 June 2001 17:45
Subject: quick terra sig question
>I'm preparing to make my first batch of terra sig from redart clay,
following Vince's recipe. I also have a big bucket of earthenware clay I dug
at a lake (wolf lake) in michigan, very plastic, grey-green stuff that fires
peach, and melts at high temps to a mustardy green; I'd like to make a small
batch of sig from that, too. But it takes, I understand, a lot of clay to
make a little sig, and the leftover clay is pretty much useless, once robbed
of its smallest platelets.
>
>So here's my question: can I use less clay by using only the finest
particles of my wolf lake clay? When I first dug it, I mixed it to a thin
slip and poured it through the strainer basket from an old washing machine
to get rid of roots and chunks. It has dried into chunks, which I "grate" on
a window screen into a bowl before adding water to make clay. What if I ran
that dry material through a finer and finer mesh, until I had just "clay
flour"? Would that put me ahead, at all, in the amount of terra sig that
would hang in suspension in the beaker?
>
>What I'm asking is, (and I apologise if this is a stupid question) -- is
there a relationship between the number of "suspendible" platelets and the
size of particles in dry clay?
>
>Thanks in advance for any opinions...
>
>Kelly Savino in Ohio
>
>_________________________________________________________________
>iVillage.com: Solutions for Your Life
>Check out the most exciting women's community on the Web
>http://www.ivillage.com
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Joyce Lee on tue 19 jun 01
ok
----- Original Message -----
From: "Khaimraj Seepersad"
To:
Sent: Tuesday, June 19, 2001 9:11 AM
Subject: Re: quick terra sig question
> Hello to All ,
>
> Kelly ,
>
> down here in the Tropics , we have quite a variety of sticky
> surface clays . So I have taken to just collecting the earth
> of our canefields.
> Now , I just collect a few lumps and dry . Then re-wet , in a
> quantity of water , pass through a -325 mesh sieve , thin
> to a watery quality and apply to the body .
>
> Polishing is when the object is dried , and has had a thin coat
> of soybean cooking oil applied and allowed to soak in .
> Cloth or plastic is used depending on what I want .
>
> The cane seems to extract Calcium Oxide from the soil , so
> these clays can be self grogged , easily fired to 1100 - 1130
> deg.c and will stand , mature and make beautiful objects.
> Bloating is at 1150 to 1180 deg.c .
> Hope this helps .
> Khaimraj
>
> * Linda , Bret and Ivor , I owe you all sensible replies , presently
> over loaded , but I will get to you .
> Thanks for your patience in advance .
> Khaimraj
>
>
>
> -----Original Message-----
> From: primalmommy@IVILLAGE.COM
> To: CLAYART@LSV.CERAMICS.ORG
> Date: 18 June 2001 17:45
> Subject: quick terra sig question
>
>
> >I'm preparing to make my first batch of terra sig from redart clay,
> following Vince's recipe. I also have a big bucket of earthenware clay I
dug
> at a lake (wolf lake) in michigan, very plastic, grey-green stuff that
fires
> peach, and melts at high temps to a mustardy green; I'd like to make a
small
> batch of sig from that, too. But it takes, I understand, a lot of clay to
> make a little sig, and the leftover clay is pretty much useless, once
robbed
> of its smallest platelets.
> >
> >So here's my question: can I use less clay by using only the finest
> particles of my wolf lake clay? When I first dug it, I mixed it to a thin
> slip and poured it through the strainer basket from an old washing machine
> to get rid of roots and chunks. It has dried into chunks, which I "grate"
on
> a window screen into a bowl before adding water to make clay. What if I
ran
> that dry material through a finer and finer mesh, until I had just "clay
> flour"? Would that put me ahead, at all, in the amount of terra sig that
> would hang in suspension in the beaker?
> >
> >What I'm asking is, (and I apologise if this is a stupid question) -- is
> there a relationship between the number of "suspendible" platelets and the
> size of particles in dry clay?
> >
> >Thanks in advance for any opinions...
> >
> >Kelly Savino in Ohio
> >
> >_________________________________________________________________
> >iVillage.com: Solutions for Your Life
> >Check out the most exciting women's community on the Web
> >http://www.ivillage.com
> >
>
>___________________________________________________________________________
> ___
> >Send postings to clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list or change your subscription
> >settings from http://www.ceramics.org/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
> >
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Snail Scott on tue 19 jun 01
At 03:43 PM 6/18/01 -0700, you wrote:
>
>So here's my question: can I use less clay by using only the finest
particles of my wolf lake clay?...What if I ran that dry material through a
finer and finer mesh, until I had just "clay flour"? Would that put me
ahead, at all, in the amount of terra sig that would hang in suspension in
the beaker?
The particle size of clay is pretty much determined
geologically. You're not making the particles smaller
by seiving; you're just filtering out the big ones.
Seiving it first couldn't hurt, to get the odd chunks
out, but even coarse clay particles are still smaller
than a pretty fine mesh screen. ( You'd have to seive
it down to about 300 mesh to make much of a difference,
I'd guess, and you'd still have all that coarse stuff
left over.)
The only way I know of to make the actual clay particles
smaller is with a hammer mill (not a common item for
most of us) or a ball mill. With a ball mill, if you
let it run for long enough, everything that went into
it will turn into terra sig eventually. You'd actually
get a 100% usable result with this method. No loss.
Ball mills aren't terribly difficult to build, and some
people report good success in adapting hobby-type rock
tumblers to the purpose.
If you haven't got a ball mill, and don't want to build
one, why not make life simple and let the coarse stuff
just settle out without all that seiving? It's removed,
either way. (Though maybe it could be used in a low-
shrinkage slip?)
-Snail
iandol on wed 20 jun 01
Dear Kelly Savino,
Good question "suspendible" platelets and the size of particles in dry clay?>
I suggest that there is no direct numerical relationship between the =
size of the particles which fall out of a well mixed clay/water =
suspension and the size of dry particles. Even dry clay, unless it has =
been baked well above the boiling point of water, but lower than the =
temperature at which each molecule looses its hydroxyl groups, will =
contain sufficient moisture for the particles to cohere into clumps and =
I doubt if anyone would go to the trouble of counting the number of one =
in one of the other.
It seems to be your wish to retain your Wolf Lake clay as the basis for =
other modelled or thrown work. My suggestion is to separate the =
superfines by sedimentation to make your Terra Sig. Replace that mass of =
material back into the sediment with a good ball clay which fires white =
or near white to restore plasticity.
I have a feeling that the size spread of clay crystals, the ones which =
are hexagonal plate shapes, is much greater than imagined. This means =
that even large clay crystals settle slowly, though they may flutter as =
they go down. But recall, most natural clays contain a lot of silt and =
sand which is composed of quartz. Although the densities of quartz and =
clay are almost the same, size for size the none clay minerals have =
greater mass per particle because they are chunky so they sink faster =
and settle out more quickly. So repeated sieving through finer and finer =
mesh, even to #200 may not be of any great help.
Learn you skill with Vince's technique with the Goldart and then get to =
work on you native clay.
There is, by the way, an implicit assumption in instructions for the =
preparation of Terra Sigillata. It is assumed that the crystals of clay =
are always flat sheets. However, many native clays contain other =
minerals. A notorious one is Halloysite. Exactly the same analytical =
composition as Kaolinite but because of a difference in the structural =
arrangement of the atoms, it forms crystals which are tube shaped. A =
second one is Montmorillonite which has an extra layer of silicon oxide =
units. in both cases they take in more water and so have a greater =
degree of shrinkage.
Wishing you every success with this venture. I hope you produce articles =
with sumptuous colourful vibrant surfaces.
Best regards,
Ivor Lewis. Redhill, South Australia.
Michael Dickman on sat 23 jun 01
>What I'm asking is, (and I apologise if this is a stupid question) -- is
>there a relationship between the number of "suspendible" platelets and the
>size of particles in dry clay?
>
>Thanks in advance for any opinions...
>
>Kelly Savino in Ohio
This is not a stupid question, just not easy to answer. The number of
suspendible platelets will vary from clay to clay and maybe even batch to
batch. Ball milling might increase that number, but it's likely more work
than it's worth. I wouldn't bother sieving any more than necessary to get rid
of the foreign material, and then make a homogeneous slip before adding
deflocculent.
- Michael Dickman
Rick Bowman on sat 23 jun 01
On the subject of terra sigs...Eleven years ago when I started out in
primitive pottery I did a series of experiments on terra sigellatas and one
of the easiest procedures follows:
Pour 2 cups of wood ash in a paper coffee filter.
Pour a cup of water thru the ash and collect in a container. It will
look like apple juice. This is your deflocculant.
Make a slurry in a bucket and pour into a tall cylinder (a glass one if
would like to see the stratified layers from fine to course particles.)
Pour about a quarter cup of the wood ash water into the tall cylinder and
wait 48 hours. Pour off the water and scoop out the closest stratified
layer to the top and throw the rest away.
Paint and burnish it into a leather hard test tile to see if it is going to
flake off. Flaking off is usually due to uneven drying between two clay
bodies, so to stop any flaking add a small amount of the clay you are
working with, to the pigment and try again.
It worked for me but try every method and pick out the one which best
suits you and your clay needs. Keep a notebook of the results of your
experiments for future references.
Rick Bowman
>From: primalmommy@IVILLAGE.COM
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: quick terra sig question
>Date: Mon, 18 Jun 2001 15:43:56 -0700
>
>I'm preparing to make my first batch of terra sig from redart clay,
>following Vince's recipe. I also have a big bucket of earthenware clay I
>dug at a lake (wolf lake) in michigan, very plastic, grey-green stuff that
>fires peach, and melts at high temps to a mustardy green; I'd like to make
>a small batch of sig from that, too. But it takes, I understand, a lot of
>clay to make a little sig, and the leftover clay is pretty much useless,
>once robbed of its smallest platelets.
>
>So here's my question: can I use less clay by using only the finest
>particles of my wolf lake clay? When I first dug it, I mixed it to a thin
>slip and poured it through the strainer basket from an old washing machine
>to get rid of roots and chunks. It has dried into chunks, which I "grate"
>on a window screen into a bowl before adding water to make clay. What if I
>ran that dry material through a finer and finer mesh, until I had just
>"clay flour"? Would that put me ahead, at all, in the amount of terra sig
>that would hang in suspension in the beaker?
>
>What I'm asking is, (and I apologise if this is a stupid question) -- is
>there a relationship between the number of "suspendible" platelets and the
>size of particles in dry clay?
>
>Thanks in advance for any opinions...
>
>Kelly Savino in Ohio
>
>_________________________________________________________________
>iVillage.com: Solutions for Your Life
>Check out the most exciting women's community on the Web
>http://www.ivillage.com
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
_________________________________________________________________
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