Hank Murrow on wed 13 dec 06
On Dec 13, 2006, at 5:30 PM, Leland Hall wrote:
> Any way, there is a family of potters in my area, who's work I have
> admired
> for well over 20 years. We took one of their workshops a few years
> ago,
> and their handout included their "Stoneware Recipe".
> One thing that stands out to my untrained eye is the use of three
> different
> fireclays. From what I've found in the books and in the archives,
> thats a
> bit unusual, is that right? From what I saw, most recipe's that rely
> on "fireclay", typically use just two?
>
> This is recipe:
>
> Hawthorne Bond...........................20
> Greenestripe.............................15
> Goldart..................................15
> OM 4 Ball................................25
> EPK kaolin...............................10
> Custer Feldspar..........................10
> 412 Grog.................................10
Dear Leland;
I cannot predict how this recipe will work out for you. However, I am
pleased to introduce you to the "Room Full of Basketballs" theory of
clay formulation, which I learned from Bob James back in the
Pleistocene(circa 1958), and confirmed in the course of compounding
many claybodies over the nearly 50 years since. The theory goes like
this: imagine a room full of basketballs. Now fill the spaces between
with tennis balls, then the remaining spaces with shooter marbles, and
peas, and buckshot, and sand grains, and fine sand. The idea is to make
sure that there is a very wide range of particle size available, so
that all particles are touching each other(or as nearly as may be
configured) so that all particles are just separated by the water that
can be held(by molecular attraction) to their surfaces. The reason
folks use several clays is to insure(in our age of over-'improved' and
therefore mono-sized clays) that there is such a range of particle
sizes. My best recipes from industrial materials usually have up to ten
ingredients, except for the superb clays which I dig and prepare
myself, which have a wide range of particle size because I retain that
quality in my preparation(starting with the digging). My favorite
'wild' porcelain consists of Calf Creek Porcelain-stone_97%, and Neph
Sye_3%. I can send you a pic of this if you like.
Cheers, Hank
www.murrow.biz/hank
Vince Pitelka on wed 13 dec 06
> Hawthorne Bond...........................20
> Greenestripe.............................15
> Goldart..................................15
> OM 4 Ball................................25
> EPK kaolin...............................10
> Custer Feldspar..........................10
> 412 Grog.................................10
Leland -
This looks like a fairly average stoneware body, and should work well. Some
fireclays have had problems with lime pops, but most stoneware claybodies
contain some fireclay. We use Hawthorne Bond extensively and have not had
any problems with it. The point of a recipe like this containing a variety
of different clays is to introduce the broadest spectrum of clay particle
sizes. That gives high plasticity while retaining reasonably low drying and
firing shrinkage. Some people might say that the inclusion of two
fireclays, a stoneware clay, a ball clay, and a kaolin is overkill, but it
certainly can't do any harm. The feldspar could be Custer or G-200, and it
ensures adequate glass formation to give true vitrification at cone 10. I
do not know what the "412" signifies in the grog, but personally, I'd go for
an extra fine grog or sand.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Leland Hall on wed 13 dec 06
Greetings,
I'm growing increasingly unhappy with the boxed clay availiable in my
area. Price is a factor, yet there are others. I have spent several days
reading my referance books, searching the archives, pouring over "what clay
is", and recipe's, and mainly have determined that I have MUCH to learn.
Any way, there is a family of potters in my area, who's work I have admired
for well over 20 years. We took one of their workshops a few years ago,
and their handout included their "Stoneware Recipe". They use it both for
their gas fired funtional ware as well as raku, much of it quite large.
Thought I'd try it, but before I try to order the three fire clays, (I have
the spar, ball, grog and EPK on hand) I thought it might be a good idea to
run it by you guys, seeing it as how ya'll know about a billion times more
than me!
One thing that stands out to my untrained eye is the use of three different
fireclays. From what I've found in the books and in the archives, thats a
bit unusual, is that right? From what I saw, most recipe's that rely
on "fireclay", typically use just two?
This is recipe:
Hawthorne Bond...........................20
Greenestripe.............................15
Goldart..................................15
OM 4 Ball................................25
EPK kaolin...............................10
Custer Feldspar..........................10
412 Grog.................................10
By the way, in the archives, I stumbled into some lengthy controversy
regarding the use of fireclaysand found it interesting reading. It would
seem that some folks think it's just not good stuff to use, though it
appears that many do.
I guess what I'm after is just some feedback from those in the know as to
what might be expected from this particular recipe. In all me reading
these past several day, I did not find it duplicated anywhere. Is this
recipe particularly unusual or anything like that? I'm thinking not, but
anything about stands out, it would be interesting to know before put in an
order for the Bond, Greenstripe and Goldart.
Thanks
Leland Hall
Before The Wheel
David Beumee on thu 14 dec 06
Thursday, Dec. 14, Leland Hall wrote:
"One thing that stands out to my untrained eye is the use of three different
fireclays. From what I've found in the books and in the archives, thats a
bit unusual, is that right? From what I saw, most recipe's that rely
on "fireclay", typically use just two?
This is recipe:
Hawthorne Bond...........................20
Greenestripe.............................15
Goldart..................................15
OM 4 Ball................................25
EPK kaolin...............................10
Custer Feldspar..........................10
412 Grog.................................10
By the way, in the archives, I stumbled into some lengthy controversy
regarding the use of fireclaysand found it interesting reading. It would
seem that some folks think it's just not good stuff to use, though it
appears that many do.
I guess what I'm after is just some feedback from those in the know as to
what might be expected from this particular recipe. In all me reading
these past several day, I did not find it duplicated anywhere. Is this
recipe particularly unusual or anything like that? I'm thinking not, but
anything about stands out, it would be interesting to know before put in an
order for the Bond, Greenstripe and Goldart."
Leland,
Hank's room full of basketballs theory is very sound, and should be followed. "Particle packing" was always a mainstay of Jim McKinnell's directive to me concerning the formulation of clay bodies. I think those properties are evident in this recipe, but I would stay away from Greenstripe because of excessive shrinkage. My choice would be to substitute New Foundry Hill Creme straight across for Greenstripe. Also, unless you like heavily grogged clay, I would recommend trying a smaller percentage of 412 grog to begin with.
You can get a slightly darker color to the body by substituting Kentucky Stone ball clay for OM-4. Also, you can get Hawthorn in two different mesh sizes. I always use the 50 mesh, but if you want coarser clay, you can use 35 mesh. Hawthorn is the fireclay source for this body, and one fireclay, in combination with the four other clays present, is plenty. Other than these suggestions, this recipe looks like a good one to me. Definately try a small batch or some small batches first before making a ton or large quantity, and carry the pots through the firing process before deciding what is right for you.
David Beumee
Earth Alchemy Pottery
Lafayette, CO
www.davidbeumee.com
-------------- Original message ----------------------
From: Leland Hall
> Greetings,
>
> I'm growing increasingly unhappy with the boxed clay availiable in my
> area. Price is a factor, yet there are others. I have spent several days
> reading my referance books, searching the archives, pouring over "what clay
> is", and recipe's, and mainly have determined that I have MUCH to learn.
>
> Any way, there is a family of potters in my area, who's work I have admired
> for well over 20 years. We took one of their workshops a few years ago,
> and their handout included their "Stoneware Recipe". They use it both for
> their gas fired funtional ware as well as raku, much of it quite large.
> Thought I'd try it, but before I try to order the three fire clays, (I have
> the spar, ball, grog and EPK on hand) I thought it might be a good idea to
> run it by you guys, seeing it as how ya'll know about a billion times more
> than me!
>
> One thing that stands out to my untrained eye is the use of three different
> fireclays. From what I've found in the books and in the archives, thats a
> bit unusual, is that right? From what I saw, most recipe's that rely
> on "fireclay", typically use just two?
>
> This is recipe:
>
>
> Hawthorne Bond...........................20
> Greenestripe.............................15
> Goldart..................................15
> OM 4 Ball................................25
> EPK kaolin...............................10
> Custer Feldspar..........................10
> 412 Grog.................................10
>
> By the way, in the archives, I stumbled into some lengthy controversy
> regarding the use of fireclaysand found it interesting reading. It would
> seem that some folks think it's just not good stuff to use, though it
> appears that many do.
>
> I guess what I'm after is just some feedback from those in the know as to
> what might be expected from this particular recipe. In all me reading
> these past several day, I did not find it duplicated anywhere. Is this
> recipe particularly unusual or anything like that? I'm thinking not, but
> anything about stands out, it would be interesting to know before put in an
> order for the Bond, Greenstripe and Goldart.
>
> Thanks
>
> Leland Hall
> Before The Wheel
>
> ______________________________________________________________________________
> 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 thu 14 dec 06
At 08:30 PM 12/13/2006 -0500, Leland H wrote:
>One thing that stands out to my untrained eye is the use of three different
>fireclays:
>Hawthorne Bond...........................20
>Greenestripe.............................15
>Goldart..................................15
>OM 4 Ball................................25
>EPK kaolin...............................10
>Custer Feldspar..........................10
>412 Grog.................................10
One good reason to use two different
clays to serve the same role is because
it makes the recipe less dependent upon
the reliability of any one ingredient.
If a single material made up 50% of your
recipe (as it would if the Hawthorne,
Greenstripe, and Goldart were replaced
by only one), any minor variation in
the analysis of that material would have
a huge impact on the behavior of the
clay body. This way, no single ingredient
makes up more than 20% of the total, and
the impact of mine variations is muted.
It makes for a very consistent clay body,
even when using inconsistent materials.
Also, though Greenstripe and Hawthorn
are pretty similar, many people classify
Goldart as a natural 'stoneware clay'
rather than a fireclay. It's a bit more
plastic than those others, so it's not
quite a duplicate. Of course, no clay is
every really a duplicate.
-Snail
Jon Pacini on thu 14 dec 06
Greetings All --- Hi Leland ---you wrote-
>One thing that stands out to my untrained eye is the use of three different
>fireclays:
>Hawthorne Bond...........................20
>Greenestripe.............................15
>Goldart..................................15
>OM 4 Ball................................25
>EPK kaolin...............................10
>Custer Feldspar..........................10
>412 Grog.................................10
As mentioned Goldart is more of a stoneware clay.
Greenstripe is an air floated California Fireclay and is the basis for many
pottery clays that have been used here over the years, including most of the
architectural terracotta that makes up San Francisco and Sacramento. It is
usually so fine and plastic that many consider it a high fire ball clay.
Hawthorne is a Missouri Flint Fireclay and is generally hammer milled and
can be quite course and prone to pop outs unless it is one of the finely
screened varieties.
All of these clays bring something different to the party. And Hanks
explanation of blending materials is a good one. Some people prefer one
fireclay over the other, everybodies techniques are different and they want
something else from their clays. It all depends on what suits you, but
technically it looks like a good general purpose clay.
The 412 grog is an obsolete Narco/Ione kaolin grog of the 35m to fine
variety.
Best regards,
Jon Pacini
Clay Manager
Laguna Clay Co
Ellen Currans on thu 14 dec 06
Dear Leland,
The Stoneware body you are asking about is very similar to one I have
been using for about 26 years. Originally I used Pine Lake Fire Clay
instead of Hawthorne but switched to Hawthorne when Pine Lake ran out.
We mix our own clay in an old Navy Dough Mixer (3 phase, which my
husband has rigged to work with our 2 phase electricity. Don't ask ME
how it works, but he could explain it to a mechanical minded person.)
Here is the formula we are using today. We mix it soft for throwing
and firm for slab work. I don't do raku but I would think it was a bit
tight for that.
Hawthorne Bond 30 (Mesh 50: Mesh 30 sometimes has junk in
it that pops out.)
Greenstripe 15 (Comes from California - thus
cheaper than some other clays.)
Kentucky ON4 Ball 17.5
XX Saggar 12.5 (We use two ball clays because for a
time OM4 was not behaving well.)
Custer Feldspar 10
Silcosil #90 10 (200 mesh)
CEMulcoa Grog 47 10 (35 mesh) This replaced the obsolete
Ione 412.
Red Iron Oxide .5 I like a toasty clay, but you could
leave this out for more strength.
I tested a lot of clay bodies when we first started making our clay and
the ones we liked the best had a variety of clays. For the reasons
already stated by others - more particle size and less chance of a huge
disaster. I had 10% Jordan clay in my original and that was the best
of all. Sigh--- I do not do huge pots, but I do make some rather
large slab trays and platters, 12 x 24 inches, etc. and have not had a
problem with cracking or warping at that size. I used this for years
for casseroles and pieplates and it worked fine. I tend not to make
pots for the oven anymore, just to avoid lawsuits,etc.
If you are a member of Oregon Potters Association you will get a
discount from Georgies when you buy in quantity. We call in our order
the day before and they put it on a pallet and shrink wrap it. Load it
on our truck when we arrive with a fork lift and we do not have to be
in such a big hurry to get it unloaded. I think these are all 50# bags
except the grog which is 100lbs.
If you have reason to come to Portland and would like to stop by the
studio and chat about any of this, please feel welcome.
We are just south of Dundee on Hwy 99 - an easy trip up the River Road
from Salem and then back on 99W to Portland.
Ellen Currans
Dundee, Oregon
-----Original Message-----
From: b4thewheel@BENDNET.COM
To: CLAYART@LSV.CERAMICS.ORG
Sent: Wed, 13 Dec 2006 5:30 PM
Subject: stoneware body
Greetings,
I'm growing increasingly unhappy with the boxed clay availiable in my
area. Price is a factor, yet there are others. I have spent several
days
reading my referance books, searching the archives, pouring over "what
clay
is", and recipe's, and mainly have determined that I have MUCH to learn.
Any way, there is a family of potters in my area, who's work I have
admired
for well over 20 years. We took one of their workshops a few years ago,
and their handout included their "Stoneware Recipe". They use it both
for
their gas fired funtional ware as well as raku, much of it quite large.
Thought I'd try it, but before I try to order the three fire clays, (I
have
the spar, ball, grog and EPK on hand) I thought it might be a good idea
to
run it by you guys, seeing it as how ya'll know about a billion times
more
than me!
One thing that stands out to my untrained eye is the use of three
different
fireclays. From what I've found in the books and in the archives,
thats a
bit unusual, is that right? From what I saw, most recipe's that rely
on "fireclay", typically use just two?
This is recipe:
Hawthorne Bond...........................20
Greenestripe.............................15
Goldart..................................15
OM 4 Ball................................25
EPK kaolin...............................10
Custer Feldspar..........................10
412 Grog.................................10
By the way, in the archives, I stumbled into some lengthy controversy
regarding the use of fireclaysand found it interesting reading. It
would
seem that some folks think it's just not good stuff to use, though it
appears that many do.
I guess what I'm after is just some feedback from those in the know as
to
what might be expected from this particular recipe. In all me reading
these past several day, I did not find it duplicated anywhere. Is this
recipe particularly unusual or anything like that? I'm thinking not,
but
anything about stands out, it would be interesting to know before put
in an
order for the Bond, Greenstripe and Goldart.
Thanks
Leland Hall
Before The Wheel
_________________________________________________________________________
_____
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
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Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
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Leland Hall on sun 17 dec 06
Thank you all so much for your generous sharing of thoughts and information
regarding a stoneware recipe I have been considering.
And sorry about the delay in offering this thanks, The Pacific Northwest
was hit with a HUGE windstorm of historic proportions thursday, and
suffered massive power outages with flooding from Seattle down the coast
into Oregon I don't know how far. We have many many trees down here in
Central Oregon, and many parts of La Pine were without power for over 48
hours. We just got back up and running Sat. evening, and all this with
subzero temps! My best wishes go out to those affected by this storm, and
wish you speedy recovery.
Best wishes,
Leland Hall
Before The Wheel
La Pine Oregon
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