Autumn Downey on fri 12 dec 97
How much difference does water make to throwing slips?
When I use Plainsman M370 here in Yellowknife, the slip in the bottom of the
bucket and pan become cement-like, and there is a powdery layer that doesn't
want to mix back in - really bad for recycling.
In Saskatchewan, this doesn't happen. The slip remains suspended, sometimes
for longer than I'd like - if I was planning to pour off the water.
Water in the north is quite soft - maybe a little acidic. On the prairies,
it's alkaline - the taps grow stalactites. Could this account for the
difference in the slips?
Can one add something to the water here - a little Epsom's salts or
something else? a tsp per water bucket?
Thanks!!
Autumn Downey
downeya@internorth.com
Yellowknife, NWT, Canada
Tom Wirt/Betsy Price on sat 21 apr 01
Subject: Re: throwing water
> That's because new potters look at all the photographs to learn
from, that
> the experienced potters took for effect! ;)
>
And Marianne, that's why those experienced potters get those pictures
taken....to mislead the new potters and slow them down from overtaking
them,....damn young Turks!
:>)
Tom
mel jacobson on sat 21 apr 01
hmmm, a thought. (s)
1. full time, older potters use very little water when throwing.
(we use a great deal when taking photos of us throwing.
for that visual effect, cool.)
2. new potters, young potters flood pots with water.
let about 2 inches stand in the bottom while throwing.
3. old potters rarely have s cracks.
4. young potters have lots of s cracks.
5. perhaps we can conclude that standing water
weakens the base of pots and creates the possibility
of s cracks.
6. old potters throw very swiftly. get it on, get it off.
7. young potters throw slow, take many minutes to
get pots done...water soaks in.
8. most japanese potters use an inside rib to throw with.
the amount of energy that is applied to the bottom of pots
is immense. it sure compacts, compresses, constricts the
base of the clay. take a full time thrower in kyoto, wooden
rib in hand, push down hard into a spinning pot...now that
is compression. i never once saw an s crack in japan.
it is unheard of.
9. when hump throwing, as each pot is removed, the entire
hump is coned two or three times...fresh clay.
no s cracks. (australian, scientist potter smiles.)
10.
hmmm, some things to add to the mix.
mel
From:
Minnetonka, Minnesota, U.S.A.
web site: http://www.pclink.com/melpots
Marianne Lombardo on sat 21 apr 01
That's because new potters look at all the photographs to learn from, that
the experienced potters took for effect! ;)
> 2. new potters, young potters flood pots with water.
> let about 2 inches stand in the bottom while throwing.
>
vince pitelka on sat 21 apr 01
Mel -
I appreciate your comments on throwing water. Most of us use way too much
water. Gail Nichols came back from NCECA with us, and spent a week working
with my students and then did a weekend workshop. She has a wonderful
easy-going throwing style, and never uses a splash pan. When she throws,
the outer rim of the wheel never gets wet. Richard Bresnahan throws the
same way. Just enough water on the fingers to provide necessary
lubrication. The other important ingredient is to throw with soft clay on a
slow wheel. One of the negative features of the electric wheel is that it
opens up a much higher speed range which does little good and causes many
problems. At that speed, you have to use a lot of water.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
----- Original Message -----
From: mel jacobson
To:
Sent: Saturday, April 21, 2001 2:58 PM
Subject: throwing water
> hmmm, a thought. (s)
>
> 1. full time, older potters use very little water when throwing.
> (we use a great deal when taking photos of us throwing.
> for that visual effect, cool.)
>
> 2. new potters, young potters flood pots with water.
> let about 2 inches stand in the bottom while throwing.
>
> 3. old potters rarely have s cracks.
> 4. young potters have lots of s cracks.
>
> 5. perhaps we can conclude that standing water
> weakens the base of pots and creates the possibility
> of s cracks.
>
> 6. old potters throw very swiftly. get it on, get it off.
> 7. young potters throw slow, take many minutes to
> get pots done...water soaks in.
>
> 8. most japanese potters use an inside rib to throw with.
> the amount of energy that is applied to the bottom of pots
> is immense. it sure compacts, compresses, constricts the
> base of the clay. take a full time thrower in kyoto, wooden
> rib in hand, push down hard into a spinning pot...now that
> is compression. i never once saw an s crack in japan.
> it is unheard of.
>
> 9. when hump throwing, as each pot is removed, the entire
> hump is coned two or three times...fresh clay.
> no s cracks. (australian, scientist potter smiles.)
>
> 10.
> hmmm, some things to add to the mix.
> mel
> From:
> Minnetonka, Minnesota, U.S.A.
> web site: http://www.pclink.com/melpots
>
>
____________________________________________________________________________
__
> 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.
>
elizabet on sat 21 apr 01
Robin Hopper is the exception to that. He throws with tons of water....he says he
like to throw *clean* and his hands ARE clean.
Elizabeth
Marianne Lombardo wrote:
> That's because new potters look at all the photographs to learn from, that
> the experienced potters took for effect! ;)
>
> > 2. new potters, young potters flood pots with water.
> > let about 2 inches stand in the bottom while throwing.
> >
>
Gail Dapogny on sun 22 apr 01
Thanks, Elizabeth!
While I've never wanted to argue with the notion that "dry " throwing is
best, I have always wished that people wouldn't state it as if it were were
a fact or an absolute. All of these parts of the process are so
individual.
Robin Hopper does indeed throw wet, and so did Kurt Weiser when he was in
this area of the country. This past week, I watched Peg Malloy throw --
she is a beautiful thrower of fine, elegant pots, and freely admits to
using lots of water. And didn't Phil Rogers say sometime recently that he
likes to use a fair bit of water? Some of us are just more confortable with
it wet!
---Gail
>Robin Hopper is the exception to that. He throws with tons of water....he
>says he
>like to throw *clean* and his hands ARE clean.
>
>Elizabeth
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
C TRIPP on sun 22 apr 01
One of my teachers must have learned it from him because she had us up and
down like jack-in-the-boxes all through class, "You water is dirty.* Go get
some clean water." It drove me nuts but I didn't know any differently until
I read an article by Ivor Lewis where he wrote about using slury to throw.
What a revelation! And a lot less jumping about too.
(*Imagine, describing throwing water as dirty. Just what did she think we
were working with?)
Carol
> Robin Hopper is the exception to that. He throws with tons of water....he
says he
> like to throw *clean* and his hands ARE clean.
>
> Elizabeth
>
> Marianne Lombardo wrote:
>
> > That's because new potters look at all the photographs to learn from,
that
> > the experienced potters took for effect! ;)
> >
> > > 2. new potters, young potters flood pots with water.
> > > let about 2 inches stand in the bottom while throwing.
> > >
> >
>
>
______________________________________________________________________________
> 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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Bruce Girrell on sat 28 apr 01
Harold Scoggins wrote:
>For instance, the suggestion that void space in clay is so "convoluted"
>that it hampers liquid flow is only a partial description of a process
>and not an "answer."
This may be considered "not an answer" because I didn't feel it necessary=
or
enlightening to go find my references and supply the appropriate formulas=
.. I
can substantiate my claims if you so wish, but I doubt that it will be of
little more than academic interest.
>Once the void space is saturated (filled) the flow
>is a linear function of the total volume of void space occupied by
>water. This is a fact, not opinion.
But where in the world did you get this??? Did someone suspend Darcy's la=
w
recently? Are you telling me that a 40% porosity sandstone and a 40%
porosity clay will have equal flow characteristics once each has been
saturated with water?
The Kozeny-Carman equation states that the square root of the quantity
equals the quantity by
1 minus porosity> times the inverse of the quantity <"shape factor" times
tortuosity times surface area per unit grain volume>.
Does that sound like a linear relationship with porosity?
If we solve the above relationship for permeability, we get permeability
equals the quantity porosity> squared> times the inverse of the quantity <"shape factor" squa=
red
times tortuosity squared times squared>. =
If
we assume a porosity of 0.4 (40%), then the porosity term becomes 0.17777=
7
and we are left with permeability is proportional to the inverse of <"sha=
pe
factor" times tortuosity times > squared. T=
he
"shape factor and surface area per grain volume terms are related to
capillary forces and surface tension. Tortuosity is how convoluted the po=
re
channels are.
So what in my original answer was not an answer and what support do you h=
ave
for the "fact" that flow is a linear function of the total volume of void
space occupied by water?
Bruce Girrell
mel jacobson on mon 27 jan 03
several things to consider:
using water is just fine...it depends on how long
it takes to throw the pot. if you are speedie, get
right at it...three minutes or so, use all the water
you want.
if you are slow, deliberate, use slip...cut back
the water.
there is no one answer to this question.
young potters, (not age, but experience) will often
flood the pot, take 30 minutes to make the pot, then
find the clay has no integrity.
in japan, we used lots of clean water...but, no pot was
on the wheel for more than two minutes.
if i had to make jars with tall necks...well, used
slip. no water flooding.
so, often we get a post that say's...`hell you have to use
slip only...or , only fresh water every thirty seconds....`
no one asks the question `how do you throw, at what speed, and
what kind of pots?`
makes a big difference.
if you like water, use deliberate throwing skill...continue
to use it. i love clean water...about 80 degrees F.
i have two 5 gallon pickle (green) buckets of clean
water in the studio. works great.
bring in two gallons of hot water each day.
have a small microwave to heat a quart or so at a time.
for my throwing bucket.
works.
mel
From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
Christena Schafale on mon 27 jan 03
For winter throwing in my unheated basement, I've been really enjoying
using my crockpot as a throwing bucket. Turn it on for a little while when
I first go down there, then off when it starts to get too warm, back on
again later if need be. This way I get to keep all that lovely slip from
day to day and still have it warm to throw with.
One warning -- I leave my chamois, attached to a fishing bobber, floating
in the bucket. One day I forgot and left the crockpot turned on
overnight. All was well, except the chamois was cooked -- it shrank to
about half its former length and was much less flexible than before.
Chris
>Mel says:
>have a small microwave to heat a quart or so at a time.
>for my throwing bucket.
>works.
Consultation and Referral Specialist
Resources for Seniors
christenas@rfsnc.org
http://www.resourcesforseniors.com
Phone: (919) 713-1537
FAX: (919) 872-9574
1110 Navaho Dr, Suite 400
Raleigh, NC 27609
claybair on mon 27 jan 03
Hmmmmm......Thanks for the recipe for
Christena's Chamois soup....... sounds lovely.
What wine do you recommend? White/Red?
Dessert some Ron & John Raspberry Mousse?-)
I usually just bring out a bucket of hot tap water to the studio.
The first year I cavalierly used cold water and boy did my hands
get red and chapped!
I would worry about turning off a crock pot. Isn't there some
heater for farm water troughs? Knowing me, I would probably wind up coming
down to the studio at 4 in the morning to make sure I had turned it off.
BTW have you ever used a small piece of drycleaner
plastic bag instead of a chamois? I got tired of losing the chamois
then went to the plastic and now just use the side of my finger.....
one less thing to worry about misplacing.
Fishing bobbers are great, I use them on my trim wires.
Gayle Bair..... haven't misplaced a finger yet!
Bainbridge Island, WA
http://claybair.com
-----Original Message-----
From: Christena
Schafale
For winter throwing in my unheated basement, I've been really enjoying
using my crockpot as a throwing bucket. Turn it on for a little while when
I first go down there, then off when it starts to get too warm, back on
again later if need be. This way I get to keep all that lovely slip from
day to day and still have it warm to throw with.
One warning -- I leave my chamois, attached to a fishing bobber, floating
in the bucket. One day I forgot and left the crockpot turned on
overnight. All was well, except the chamois was cooked -- it shrank to
about half its former length and was much less flexible than before.
Chris
>Mel says:
>have a small microwave to heat a quart or so at a time.
>for my throwing bucket.
>works.
clennell on mon 27 jan 03
Sour Cherry Pottery
> several things to consider:
>
> using water is just fine...it depends on how long
> it takes to throw the pot. if you are speedie, get
> right at it...three minutes or so, use all the water
> you want.
>
> if you are slow, deliberate, use slip...cut back
> the water.
>
> there is no one answer to this question.
>
> young potters, (not age, but experience) will often
> flood the pot, take 30 minutes to make the pot, then
> find the clay has no integrity.
>
> in japan, we used lots of clean water...but, no pot was
> on the wheel for more than two minutes.
mel: I think this is a good answer. I had two students last year that
threw dirty. they always looked dirty, covered with slip. I would walk by
and fill up their throwing buckets with warm clean water. I said you live
by one of the Great Lakes for god's sake, use water and throw clean. their
pots looked muddy, laboured and yucky to the touch. they were also the
slowest throwers in the group.
I taught a workshop this past fall where the guy was using a little yogurt
container for a water container. Hells bells I said, you'd think water was
Drambuie.
The programme I was taught in (set up by Robin Hopper) with guests like
Micheal Cardew and Harry Davis, you were taught to make 2 pulls for height
and the third and final pass over the clay was for shape. Slam, bam, thank
you, mame. No fuss, no muss!Here's a Harry D trick for you. Pull the cutting
wire towards you to cut off the pot, wire sits on your lap, next pot, wire
goes under pot and rests on water bucket, next pot towards you and on lap,
etc, etc. Some will say this saves only a few seconds! Yes and these guys
made pots by the hundreds each day. Time management is not unique to big
business.
My favourite Harry Davis quote " Unless you have independent means, you had
better learn how to make cups and make them bloody fast".
cheers,
Tony
John Rodgers on mon 27 jan 03
For automatic shutoff of electrical appliances at the end of your studio
session, install a plug-in timer into your electrical outlet(s). They
are usually under $10 and are available through most hardware stores,
and prol'ly places like Walmart. I got mine at a Lowe's Building Supply
Center.
John Rodgers
Birmingham, AL
claybair wrote:
>I would worry about turning off a crock pot. Isn't there some
>heater for farm water troughs? Knowing me, I would probably wind up coming
>down to the studio at 4 in the morning to make sure I had turned it off.
>
>
>
OWLPOTTER@AOL.COM on tue 28 jan 03
Near me in Michigan there are specialty stores that sell bird seed, bird
feeders, etc. They also sell a small electric heater to leave out in the
bird bath to keep it thawed. It is meant to be left on 24 hrs a day, and
doesn't heat the water warm enough to affect the birds. Works great in my
throwing bucket.
-Carolynn Palmer, Somerset Center, Michigan
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