Randall Moody on sat 19 jun 10

On Sat, Jun 19, 2010 at 8:51 PM, Steve Slatin wrote=
:

> Randall --
>
> OK, you've established that opinions differ.
>
> How about doing a quick test to find out?
>
> Weigh a bit of clay at your idea of perfect
> working moisture.
>
> Bisque it, eliminating all water.
>
> Weigh it again.
>
> The difference is the weight of the
> water, plus LOI ingredients (mostly
> carbonaceous, though there are others).
>
> You now have an actual established
> factual basis for a % weight of water
> to dry clay ingredients ...
>
> Steve Slatin --
>
>
>
Great idea Steve! I will have to wait until the semester starts at the art
center but I will do that and publish the results here when it is finished.
--
Randall in Atlanta
http://wrandallmoody.com/home.html

Steve Slatin on sat 19 jun 10

Randall --

OK, you've established that opinions differ.

How about doing a quick test to find out?

Weigh a bit of clay at your idea of perfect
working moisture.

Bisque it, eliminating all water.

Weigh it again.

The difference is the weight of the
water, plus LOI ingredients (mostly
carbonaceous, though there are others).

You now have an actual established
factual basis for a % weight of water
to dry clay ingredients ...

Steve Slatin --



--- On Thu, 6/17/10, Randall Moody wrote:

> I was looking over my recipes for
> clay bodies and realized that none of them
> recommend an amount of water. Does anyone have a percentage
> or weight for
> 100 pounds of clay?
> I know this may be a personal preference for softness or
> stiffness but a
> general figure would help.
>
> Thanks
>
> --
> Randall

douglas fur on sat 19 jun 10

Randall
The 20-25% number is the "water of plasticity" which is the minimum ammount
that makes the clay work. The question is "how much do you add to get all
the clay particles wet?"

("Consider the following"- Look at dry clay, there's not much you can do
with it. Add some water and that makes it workable. Wouldn't it be more
accurate to think "I'm throwing water' instead of "I'm throwing clay"?)

I'm with Ivor on the "slop method" for every pond of clay I'd put in 3/4 to
one pound of water. Then let it sit at least 24 hours, blunge and take out
the excess water. {the classic industrial slop method is: all ingredients
are held as slips in tanks and are constantly stirred; bodies are measured
out by volume, pints of clay pints of feldspar etc; mixed wet and then
dried}

Anything else than giving the clay excess water is shorting yourself in
quality of the clay you want to work with. Why make your job harder than it
is? Let the water do the work.

Forcing the "right ammount" of water into a clay by mechanical means ends
up with alot of lumps of clay particles coated with a layer of slip which
slows down the waters penetration into the individual particles inside thos=
e
clumps.

I have mixed some clay by dry mixing in a sealable container and then addin=
g
25% water. Seal the container and wait for the water to soak in (a couple
of weeks for a 700 lb. batch. Several days for a 15 lb. batch)
To me this system worked better than the same materials run in a dough
mixer.

DRB
Seola Creek

Eric Hansen on sat 19 jun 10

p.s. having a clay mixer would be GREAT - see my blog site
americanpotter.blogspot.com
this no-mixer method uses a LOT of muscle which is hard on my damaged
overworked right shoulder. The triangular trowel is a tool every potter
should have however, it maximizes the amount of clay you can move with
minimum strength.
-h-

On Sat, Jun 19, 2010 at 1:16 PM, Eric Hansen
wrote:

> Well according to these other Clayarters, this would have come up too wet=
.
> I wonder what he reason for that could have been. When I make clay I don'=
t
> measure the water. Good question.
> -h-
>
>
> On Fri, Jun 18, 2010 at 5:22 PM, Eric Hansen <
> eric.hambone.hansen@gmail.com> wrote:
>
>> Stephen Hill used to figure about 50 lbs of water to 100 lbs. of dry cla=
y
>> =3D
>> 150 lbs moist clay, and pug mill it in the morning, according to the
>> former
>> apprentice to whom he sold his first studio. I got this at the Jonathon
>> Smith workshop we had at KU. They way they did it was it was wetter when
>> the
>> left it that it was in the morning when they came back to work, because
>> the
>> clay particles absorb all that water over night. But of course this is
>> going
>> to vary from one recipe to another, and the recipe he used was mostly
>> fireclay with ball clay. You may want to approach this cautiously, you
>> know
>> what they say about free advice.
>> - h -
>>
>> On Thu, Jun 17, 2010 at 10:57 PM, Randall Moody >> >wrote:
>>
>> > I was looking over my recipes for clay bodies and realized that none o=
f
>> > them
>> > recommend an amount of water. Does anyone have a percentage or weight
>> for
>> > 100 pounds of clay?
>> > I know this may be a personal preference for softness or stiffness but=
a
>> > general figure would help.
>> >
>> > Thanks
>> >
>> > --
>> > Randall in Atlanta
>> > http://wrandallmoody.com/home.html
>> >
>>
>
>

Eric Hansen on sat 19 jun 10

Well according to these other Clayarters, this would have come up too wet. =
I
wonder what he reason for that could have been. When I make clay I don't
measure the water. Good question.
-h-

On Fri, Jun 18, 2010 at 5:22 PM, Eric Hansen
wrote:

> Stephen Hill used to figure about 50 lbs of water to 100 lbs. of dry clay=
=3D
> 150 lbs moist clay, and pug mill it in the morning, according to the form=
er
> apprentice to whom he sold his first studio. I got this at the Jonathon
> Smith workshop we had at KU. They way they did it was it was wetter when
> the
> left it that it was in the morning when they came back to work, because t=
he
> clay particles absorb all that water over night. But of course this is
> going
> to vary from one recipe to another, and the recipe he used was mostly
> fireclay with ball clay. You may want to approach this cautiously, you kn=
ow
> what they say about free advice.
> - h -
>
> On Thu, Jun 17, 2010 at 10:57 PM, Randall Moody > >wrote:
>
> > I was looking over my recipes for clay bodies and realized that none of
> > them
> > recommend an amount of water. Does anyone have a percentage or weight f=
or
> > 100 pounds of clay?
> > I know this may be a personal preference for softness or stiffness but =
a
> > general figure would help.
> >
> > Thanks
> >
> > --
> > Randall in Atlanta
> > http://wrandallmoody.com/home.html
> >
>

Clyde Tullis on sun 20 jun 10

In batches where there is no recycle involved I always weigh the water. T=
=3D
hat
way I can add most of it first and begin by adding the small items like
Barium Carb, fiber, talc, etc. to make sure they are well dispersed. I th=
=3D
en
add the remaining water as needed.

Do you adjust the PH?

Lee Love on sun 20 jun 10

On Sun, Jun 20, 2010 at 1:54 PM, Paul Herman w=
=3D
rote:
> Randall,
>
> I use about 10 pounds of water for 35 pounds of clay body.
>
> Steve's idea below will not only drive off the water of plasticity, it
> will also remove the chemically combined water from the clay minerals,
> and give you an inaccurate number. I think what you need to know is
> the amount of the water of plasticity. You could find that out by
> heating the clay sample in a conventional oven at 250F, instead of
> using a bisque firing.

Maybe bone dry would work.

--
Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/

=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi

Lee Love on sun 20 jun 10

On Sat, Jun 19, 2010 at 9:09 PM, Randall Moody wr=
=3D
ote:


>> You now have an actual established
>> factual basis for a % weight of water
>> to dry clay ingredients ...

Before you add water for plasticity, there is water in your unfired
clay. This it is what allows it to take plastic form. After bisque,
your clay cannot become plastic again.

Here is an example in soil, differentiating mineral and water loss in
soil as ratios of LOI%:

"soil samples analyzed, the range of mineral water loss is 0.56 to
2.45%. Depending on the LOI values of the soil samples, the
SoilWaterLoss:LOI ratios range from 0.04 to around 1.00."

Found here:
http://www-usr.rider.edu/~hsun/carbon.pdf



--
Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/

=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi

Paul Herman on sun 20 jun 10

Randall,

I use about 10 pounds of water for 35 pounds of clay body.

Steve's idea below will not only drive off the water of plasticity, it
will also remove the chemically combined water from the clay minerals,
and give you an inaccurate number. I think what you need to know is
the amount of the water of plasticity. You could find that out by
heating the clay sample in a conventional oven at 250F, instead of
using a bisque firing.

best wishes,

Paul Herman

Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/




On Jun 19, 2010, at 7:09 PM, Randall Moody wrote:

> On Sat, Jun 19, 2010 at 8:51 PM, Steve Slatin
> wrote:
>
>> Randall --
>>
>> OK, you've established that opinions differ.
>>
>> How about doing a quick test to find out?
>>
>> Weigh a bit of clay at your idea of perfect
>> working moisture.
>>
>> Bisque it, eliminating all water.
>>
>> Weigh it again.
>>
>> The difference is the weight of the
>> water, plus LOI ingredients (mostly
>> carbonaceous, though there are others).
>>
>> You now have an actual established
>> factual basis for a % weight of water
>> to dry clay ingredients ...
>>
>> Steve Slatin --
>>
>>
>>
> Great idea Steve! I will have to wait until the semester starts at
> the art
> center but I will do that and publish the results here when it is
> finished.
> --
> Randall in Atlanta
> http://wrandallmoody.com/home.html

Clyde Tullis on mon 21 jun 10

We are talking about the water of plasticity here. If you bisque your te=
=3D
st
you are removing any chemically combined water as well as the carbonaceou=
=3D
s
materials. It is best to remove only the water of plasticity by heating t=
=3D
he
bone dry test to 220 F and then weighing it.

ivor and olive lewis on mon 21 jun 10

Dear Douglas Fur,



Slop Mixing ! ! We follow a long and widespread tradition.



You suggest " Wouldn't it be more accurate to think "I'm throwing water"
instead of "I'm throwing clay"? "

As I have pointed out previously, ridiculous as your proposition may sound
you make a lot of sense if you recast your idea to express the water to
solids ratio in volumetric terms.



Furthermore, in bodies that contain a total of upwards of fifty percent
granular material in the form of fluxes and vitrifiable minerals (porcelain
bodies) the volume of water exceeds the volume of phyllosilicate clays.

Best regards,

Ivor Lewis,
REDHILL,
South Australia

ivor and olive lewis on mon 21 jun 10

Dear Clyde Tullis,

You ask, "Do you adjust the PH?"



No need. I use rainwater which is slightly acidic.



Regards,



Ivor Lewis,
REDHILL,
South Australia

Eric Hansen on mon 21 jun 10

Douglas - There is an alternative tradition - and I believe it has it's own
science - in coil and anvil method the potter has a large mound of dried an=
d
hammerized clay, then they add a little water, just enough to form the
coils, which they pass down the assembly line. The next potter forms the po=
t
with paddle and anvil. The pot is drying quickly as it is formed, thinned,
and compressed. Water simply does not have time to penetrate all the
particles, but actually controlling excess plasticity is important in
coil-forming. Same general principles - that soaking and blunging make clay
more plastic, in this case it is avoided because the potter wants to limit
plasticity.

And then there is a curious method of making coil and anvil out of wads of
clay, they do this in Nigeria (another Cardew reference here) you can see i=
t
on YouTube
- h -


On Sat, Jun 19, 2010 at 4:46 PM, douglas fur <23drb50@gmail.com> wrote:

> Randall
> The 20-25% number is the "water of plasticity" which is the minimum ammou=
nt
> that makes the clay work. The question is "how much do you add to get al=
l
> the clay particles wet?"
>
> ("Consider the following"- Look at dry clay, there's not much you can do
> with it. Add some water and that makes it workable. Wouldn't it be more
> accurate to think "I'm throwing water' instead of "I'm throwing clay"?)
>
> I'm with Ivor on the "slop method" for every pond of clay I'd put in 3/4 =
to
> one pound of water. Then let it sit at least 24 hours, blunge and take ou=
t
> the excess water. {the classic industrial slop method is: all ingredient=
s
> are held as slips in tanks and are constantly stirred; bodies are measure=
d
> out by volume, pints of clay pints of feldspar etc; mixed wet and then
> dried}
>
> Anything else than giving the clay excess water is shorting yourself in
> quality of the clay you want to work with. Why make your job harder than =
it
> is? Let the water do the work.
>
> Forcing the "right ammount" of water into a clay by mechanical means end=
s
> up with alot of lumps of clay particles coated with a layer of slip which
> slows down the waters penetration into the individual particles inside
> those
> clumps.
>
> I have mixed some clay by dry mixing in a sealable container and then
> adding
> 25% water. Seal the container and wait for the water to soak in (a coupl=
e
> of weeks for a 700 lb. batch. Several days for a 15 lb. batch)
> To me this system worked better than the same materials run in a dough
> mixer.
>
> DRB
> Seola Creek
>

Clyde Tullis on tue 22 jun 10

I use city water that is treated to make it slightly base and add vinegar=
=3D
. I
messured it once but no I just pour some in. In school we used beer - Coo=
=3D
rs
because it isn't pasteurized. This was in the name of kick starting the
aging process.

ivor and olive lewis on tue 22 jun 10

Dear Lee Love,

Although using the "Bone Dry" sample seems to be rational it is flawed.

I believe the Laboratory Protocol suggests drying at 105 deg C (221 deg F)
for a specified time. This not only removes free water, it also strips wate=
r
molecules that are bound to the surface of clay particles by the process of
Adsorption.

Best regards,

Ivor Lewis,
REDHILL,
South Australia