jon singer on tue 1 jul 08
Here's my 2 cents:
I started with porcelain, and I love the stuff. It
feels silky on my hands when I'm throwing, isn't
really any harder to throw or trim than any other
type of clay body, and takes glazes beautifully:
http://www.jossresearch.org/pictures/hankbowl.jpg
(Helios porcelain, my Rutile Blue glaze, cone 10r.
Special thanks to Hank Murrow for teaching this form
in workshops, and for providing a tutorial on his
Web page.)
IMHO, the mystique and bizarre reputation are,
at least today, undeserved.
That said, though, we need to remember that the
porcelain we're talking about here is a modern
commercial product that is significantly different
from the early versions.
If you want a small amusement, try mixing up a
"classic" European porcelain body, using a primary
kaolin such as Grolleg or Super Standard. (A
typical mixture is 50 Kaolin, 25 K-Spar, and 25
Silica). Add nothing but water, and see what you
can do with the stuff.
[I like the plasticity test where you roll a little
cylinder about the size and shape of a pencil or
a Japanese chopstick, and try to tie a simple knot
in it. Even with Grolleg, which contains a little
bit of mica and is more plastic than a lot of other
primary kaolins, the result is just laughable.]
What I'm trying to indicate is that I think we have
a pretty good idea where the mystique came from:
the early porcelains _were_ hard to deal with. But
that was then, and this is now. It's a different
world, and the time for that particular mystique
has come and gone.
...What I think.
Cheers --
jon
John Britt on tue 1 jul 08
Hey Jon,
I use that porcelain recipe, which I call Leach Porcelain. It is a great
body. I use it with Grolleg. I think it is sold commerically under
various names. I use Custer Feldspar and others use G-200.
One interesting thing I have my students do to learn about plasticity is
to make up the recipe:
Grolleg 55
Custer Feldspar 25
Silica (200) 25
in a 1000g batch. (about 2 pounds) Then add water and wedge and try to
throw something.
Then make up 1000 gram batch and wet mix it and dry it a bit on plaster.
That will drastically increase plasticity because you get water around al=
l
the clay particles. You can also extend the blunging period to increase
plasticity.
Then I have them make up 1000 g and add 2 % bentonite, wet mix and test.
Then the 1000 g and add 2% macaloid, wet mix and test.
It is really informative and shows the effects of water and plasticizers.
You can also experiment with additions of cider vinegar(an
acid/flocculant), beer, and time.
Hope you are well,
John Britt
www.johnbrittpottery.com/wks/htm
Hank Murrow on wed 2 jul 08
On Jul 2, 2008, at 8:36 PM, Lee Love wrote:
> On Wed, Jul 2, 2008 at 4:40 PM, Hank Murrow wrote:
>> On Jul 2, 2008, at 8:44 AM, Lee Love wrote:
>>
>> clays for which you had to 'work a little harder'. He described the
>> Mashiko clays as 'sandy'; but I think they are 'silty', having used
>> them there.
>
> What you used in Mashiko Hank, was not Mashiko clay, but a blend with
> an iron bearing clay and shigaraki. All the co-op's clay is blended
> with Shigaraki nami, so it can be fired to cone 10. Mashiko Nami is
> light colored and is found between seams of yellow sand. The co-op
> also lets the clay dry hard before they blundge it.
>
> You have to go to the quarry to get straight Mashiko clay. Very
> few potters in Mashiko use it today.
Was what Kamiya Shouichi using Mashiko Nami?
Cheers, Hank
>
Lee Love on wed 2 jul 08
On Tue, Jul 1, 2008 at 5:21 PM, John Britt wrote:
> It is really informative and shows the effects of water and
>plasticizers.
Mashiko Nami clay (common clay) isn't the best. But the clay I buy
from the quarry is dug out of a pond, is made into a slurry, put
through screens, dried a little, and then pugged. The clay is never
dried out. It really helps the throwing quality of "not so good"
clay, as does the mixed particle size.
It feels different. First thing I noticed about clay back home is
that it seems very sticky compared to Mashiko clay.
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"We are such stuff as dreams are made on, and our little life is
rounded with a sleep." --PROSPERO Tempest Shakespeare
Hank Murrow on wed 2 jul 08
On Jul 2, 2008, at 8:44 AM, Lee Love wrote:
> On Tue, Jul 1, 2008 at 5:21 PM, John Britt wrote:
>
>> It is really informative and shows the effects of water and
>> plasticizers.
>
> Mashiko Nami clay (common clay) isn't the best. But the clay I buy
> from the quarry is dug out of a pond, is made into a slurry, put
> through screens, dried a little, and then pugged. The clay is never
> dried out. It really helps the throwing quality of "not so good"
> clay, as does the mixed particle size.
>
> It feels different. First thing I noticed about clay back home is
> that it seems very sticky compared to Mashiko clay.
Hamada mentioned this when he first tried the clays provided to him
by Susan Peterson at the workshop in '63 at USC. He said he preferred
clays for which you had to 'work a little harder'. He described the
Mashiko clays as 'sandy'; but I think they are 'silty', having used
them there.
Cheers, Hank
Lee Love on wed 2 jul 08
On Wed, Jul 2, 2008 at 4:40 PM, Hank Murrow wrote:
> On Jul 2, 2008, at 8:44 AM, Lee Love wrote:
>
> clays for which you had to 'work a little harder'. He described the
> Mashiko clays as 'sandy'; but I think they are 'silty', having used
> them there.
What you used in Mashiko Hank, was not Mashiko clay, but a blend with
an iron bearing clay and shigaraki. All the co-op's clay is blended
with Shigaraki nami, so it can be fired to cone 10. Mashiko Nami is
light colored and is found between seams of yellow sand. The co-op
also lets the clay dry hard before they blundge it.
You have to go to the quarry to get straight Mashiko clay. Very
few potters in Mashiko use it today.
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"We are such stuff as dreams are made on, and our little life is
rounded with a sleep." --PROSPERO Tempest Shakespeare
John on thu 3 jul 08
Several people have written and asked if the recipe I gave was correct =
because it added to 105%
Grolleg 55
Custer Feldspar 25
Silica (200 mesh) 25
It is correct and if you have ever made a big batch of clay you know =
that you don't weigh it on a studio triple beam. You try to make it up =
by full bags, if possible. It is just easier to cut open a full, =
preweighted bag.
Since Grolleg comes in 55 pound bags, when you make up a batch, you can =
just use two bags of Grolleg and one bag of feldspar and one bag of =
silica. Both the feldspar and silica come in 50 pound bags. =20
Thanks,
John Britt
www.johnbrittpottery.com/wks.htm
http://ncclayclub.blogspot.com/
Lee Love on thu 3 jul 08
On Thu, Jul 3, 2008 at 12:03 AM, Hank Murrow wrote:
> On Jul 2, 2008, at 8:36 PM, Lee Love wrote:
> Was what Kamiya Shouichi using Mashiko Nami?
No. Nami is a light colored clay. (Nami means "common.") Shochan's
clay has iron in it. But like Mashiko nami, his clay is less
refractory than the co-op's clay that is blended with Shigaraki Nami.
Shigaraki clay has more alumina in it.
Traditionally Mashiko Nami is only fired to cone 8. Kawada san at
the quarry, always warns new potters that his clay is not commercial
and is more temperamental than the co-op's. And he says it isn't as
good as Hamada's clay, that is all mined out and came from a higher
strata.
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"We are such stuff as dreams are made on, and our little life is
rounded with a sleep." --PROSPERO Tempest Shakespeare
Lee Love on thu 3 jul 08
John,
Is there any substitute for the 325 calcined kaolin in the Mino
Shino in your book. I did substitutions of regular alumina and also
half alumina and half kaolin to see if it would work. I have also
used the lowmelt spodumene. Can I calcine Alumina Hydrate or is the
finer size important? Could you ball mill for finer particle size?
Thanks,
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"We are such stuff as dreams are made on, and our little life is
rounded with a sleep." --PROSPERO Tempest Shakespeare
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