Clayart SCtag on tue 25 sep 07
In a message dated 9/25/2007 12:54:16 P.M. Eastern Daylight Time,
fhparker@YAHOO.COM writes:
I'm trying to learn how to throw plates. Either something weird is
happening or I am hallucinating.
I throw the plate from a flattened ball of clay, develop a thicker ridge
on the outside of the roataing disk, raise this thickened ridge to 1"-
1.5", clean up the plate bottom with a plastic rib, clean up the exterior
base with a wood rib, then bend the plate's rim over to about a 15-20
degree angle (using a plastic rib with a wet sponge supporting
underneath. I wire the plate off holding the wire flat to the bat, then
set it aside to stiffen -- usually overnight. The next morning I remove
the plate and turn the bottom using a clay chuck.
The problem is that the rim -- which I form to approximately 15 degrees
from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
leather hard. Is there any way to prevent this?
Many thanks,
Fred Parker
______________________________________________________________________________
So, what angle is it after glaze firing? I assume you know there will be
some drop during the firing[s].
Meg
************************************** See what's new at http://www.aol.com
Fred Parker on tue 25 sep 07
I'm trying to learn how to throw plates. Either something weird is
happening or I am hallucinating.
I throw the plate from a flattened ball of clay, develop a thicker ridge
on the outside of the roataing disk, raise this thickened ridge to 1"-
1.5", clean up the plate bottom with a plastic rib, clean up the exterior
base with a wood rib, then bend the plate's rim over to about a 15-20
degree angle (using a plastic rib with a wet sponge supporting
underneath. I wire the plate off holding the wire flat to the bat, then
set it aside to stiffen -- usually overnight. The next morning I remove
the plate and turn the bottom using a clay chuck.
The problem is that the rim -- which I form to approximately 15 degrees
from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
leather hard. Is there any way to prevent this?
Many thanks,
Fred Parker
Marcia Selsor on tue 25 sep 07
On Sep 25, 2007, at 12:29 PM, Fred Parker wrote:
> I'm trying to learn how to throw plates. Either something weird is
> happening or I am hallucinating.
>
> I throw the plate from a flattened ball of clay, develop a thicker
> ridge
> on the outside of the roataing disk, raise this thickened ridge to 1"-
> 1.5", clean up the plate bottom with a plastic rib, clean up the
> exterior
> base with a wood rib, then bend the plate's rim over to about a 15-20
> degree angle (using a plastic rib with a wet sponge supporting
> underneath. I wire the plate off holding the wire flat to the bat,
> then
> set it aside to stiffen -- usually overnight. The next morning I
> remove
> the plate and turn the bottom using a clay chuck.
>
> The problem is that the rim -- which I form to approximately 15
> degrees
> from horizontal -- pulls up to a 30-45 degree angle as the plate
> dries to
> leather hard. Is there any way to prevent this?
>
> Many thanks,
>
> Fred Parker
Try placing a bat on top of the when as soon as it is no longer
tacky. Also leave the plate upside down on the lip after trimming.
Marcia Selsor
http://marciaselsor.com
Victoria E. Hamilton on tue 25 sep 07
Fred -
A couple of things that might help:
1. Dry your plates slowly - covered with plastic. You might even cut a
hole in the middle of the plastic so that the center of the plate is exposed
and the outer edges are covered - might help to equalize the moisture level
as the piece dries.
2. After you run the cutoff wire under the plate on the batt, try painting
some wax resist on the rim - top and bottom which will retard the drying of
the rim.
Take care -
Vicki Hamilton
Millennia Antica Pottery
Seattle, WA
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Fred Parker
Sent: Tuesday, September 25, 2007 10:29 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: [CLAYART] Plate rim question
I'm trying to learn how to throw plates. Either something weird is
happening or I am hallucinating.
I throw the plate from a flattened ball of clay, develop a thicker ridge on
the outside of the roataing disk, raise this thickened ridge to 1"- 1.5",
clean up the plate bottom with a plastic rib, clean up the exterior base
with a wood rib, then bend the plate's rim over to about a 15-20 degree
angle (using a plastic rib with a wet sponge supporting underneath. I wire
the plate off holding the wire flat to the bat, then set it aside to stiffen
-- usually overnight. The next morning I remove the plate and turn the
bottom using a clay chuck.
The problem is that the rim -- which I form to approximately 15 degrees from
horizontal -- pulls up to a 30-45 degree angle as the plate dries to leather
hard. Is there any way to prevent this?
Many thanks,
Fred Parker
____________________________________________________________________________
__
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/
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melpots2@visi.com
John Rodgers on tue 25 sep 07
That is happening due to uneven drying from rim towards the center. u
can reduce this tendency by covering the plate with plastic sheet and
allow to dry more slowly. I have found this problem to be worse on
plastic and similar bats. Switching to a plaster bat helped to alleviate
the problem - not 100 percent, but significantly so. Between the plaster
bat and the plastic sheet I have virtually no pulling of the rim as you
describe. The plaster helps do some of the drying that usually takes
place directly to the air - the latter inducing the pulling you desctibe.
Regards,
John Rodgers
Fred Parker wrote:
> I'm trying to learn how to throw plates. Either something weird is
> happening or I am hallucinating.
>
> I throw the plate from a flattened ball of clay, develop a thicker ridge
> on the outside of the roataing disk, raise this thickened ridge to 1"-
> 1.5", clean up the plate bottom with a plastic rib, clean up the exterior
> base with a wood rib, then bend the plate's rim over to about a 15-20
> degree angle (using a plastic rib with a wet sponge supporting
> underneath. I wire the plate off holding the wire flat to the bat, then
> set it aside to stiffen -- usually overnight. The next morning I remove
> the plate and turn the bottom using a clay chuck.
>
> The problem is that the rim -- which I form to approximately 15 degrees
> from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
> leather hard. Is there any way to prevent this?
>
> Many thanks,
>
> Fred Parker
>
> ______________________________________________________________________________
> 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 melpots2@visi.com
>
>
>
John Rodgers on tue 25 sep 07
I left off one thing.
You can use a hand held hair dryer - but mount it on something or you
will get really tired - and let the air blow just a bit on the rim, then
move it to the center for a while, then to the zone between the rim and
the center, changing the position every little while. Once the clay has
died enough to get a "set" in it, you are pretty much home free.
Continue drying this way until leather heard. Just be sure you have it
"wired" off the bat completely.
Regards,
John Rodgers
Chelsea, AL
Fred Parker wrote:
> I'm trying to learn how to throw plates. Either something weird is
> happening or I am hallucinating.
>
> I throw the plate from a flattened ball of clay, develop a thicker ridge
> on the outside of the roataing disk, raise this thickened ridge to 1"-
> 1.5", clean up the plate bottom with a plastic rib, clean up the exterior
> base with a wood rib, then bend the plate's rim over to about a 15-20
> degree angle (using a plastic rib with a wet sponge supporting
> underneath. I wire the plate off holding the wire flat to the bat, then
> set it aside to stiffen -- usually overnight. The next morning I remove
> the plate and turn the bottom using a clay chuck.
>
> The problem is that the rim -- which I form to approximately 15 degrees
> from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
> leather hard. Is there any way to prevent this?
>
> Many thanks,
>
> Fred Parker
>
> ______________________________________________________________________________
> 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 melpots2@visi.com
>
>
>
Gayle Bair on tue 25 sep 07
Hi Fred,
A quick question
Are you covering these plates when you set them aside overnight?
Gayle Bair
Bainbridge Island, WA
Tucson, AZ
http://claybair.com
-----Original Message-----
From: Fred Parker
I'm trying to learn how to throw plates. Either something weird is
happening or I am hallucinating.
snip>
The problem is that the rim -- which I form to approximately 15 degrees
from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
leather hard. Is there any way to prevent this?
Many thanks,
Fred Parker
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.488 / Virus Database: 269.13.30/1030 - Release Date: 9/25/2007
8:02 AM
Michael Wendt on tue 25 sep 07
Fred,
Turn the plates upside down as soon as practical.
The top is drying faster than the bottom and causing
this problem.
You may want to make some foam supports for
the plate centers to prevent sagging of the soft clay.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Dale Neese on tue 25 sep 07
Fred,
from what I read you are using a clay chuck to turn the bottom and maybe
increasing the angle by pushing down near the rim. However rims will rise as
the plates dry to leather hard as air gets to both sides and not the bottom.
It has been my experience that the rims will return to the angle in which
they were thrown once completely dry and dried slowly. I dry my plates
really slow under plastic after trimming. I never place them on their rims
to dry.
Dale Tex
"across the alley from the Alamo"
San Antonio, Texas USA
Pat Southwood on tue 25 sep 07
Fred,
Instead of throwing your plate taller and then flipping the rim out, try =
pulling up a fat bead on top of your wall. then throw that out sideways =
with a sort of sqwishing movement. You can sharpen up the profiles with =
a wooden rib.
It is physically and visually stronger and because you started off the =
clay in that direction it doesnt have the memory of standing up.
- also you can go back after a bit and throw them back down again if you =
need to.
Pat Southwood.
WJ Seidl on tue 25 sep 07
I'm with Marcia...flipping it over to dry more slowly
by trapping moisture in does help eliminate the warping.
However, there is a caveat that goes along with that...
if your center is thin, you may get some "gravimetric distortion"
(ie. slumping) of the center as it dries. I've found that leaving it
for a day or two rim down, then flipping it back over and allowing
it to dry fully was the trick that worked for me. YMMV of course.
I dry on HardieBoard, not wood or plastic, if it matters.
Best,
Wayne Seidl
Marcia Selsor wrote:
> On Sep 25, 2007, at 12:29 PM, Fred Parker wrote:
>
>> I'm trying to learn how to throw plates. Either something weird is
>> happening or I am hallucinating.
>>
>> I throw the plate from a flattened ball of clay, develop a thicker
>> ridge
>> on the outside of the roataing disk, raise this thickened ridge to 1"-
>> 1.5", clean up the plate bottom with a plastic rib, clean up the
>> exterior
>> base with a wood rib, then bend the plate's rim over to about a 15-20
>> degree angle (using a plastic rib with a wet sponge supporting
>> underneath. I wire the plate off holding the wire flat to the bat,
>> then
>> set it aside to stiffen -- usually overnight. The next morning I
>> remove
>> the plate and turn the bottom using a clay chuck.
>>
>> The problem is that the rim -- which I form to approximately 15
>> degrees
>> from horizontal -- pulls up to a 30-45 degree angle as the plate
>> dries to
>> leather hard. Is there any way to prevent this?
>>
>> Many thanks,
>>
>> Fred Parker
> Try placing a bat on top of the when as soon as it is no longer
> tacky. Also leave the plate upside down on the lip after trimming.
> Marcia Selsor
> http://marciaselsor.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
> melpots2@visi.com
>
Barbara Lewis on tue 25 sep 07
Fred: I throw my plates as Pat does. Phil Rogers has a good demonstration
in his throwing book and has demonstrated it at his workshops. This
technique also makes a collapsing rim less likely.
Also, I lay the rims down flatter than I want to allow for drying.
Good luck with your plates. Please keep us posted as to your progress and
what you find useful. Barbara
----- Original Message -----
From: "Pat Southwood"
To:
Sent: Tuesday, September 25, 2007 4:30 PM
Subject: Plate rim question
Fred,
Instead of throwing your plate taller and then flipping the rim out, try
pulling up a fat bead on top of your wall. then throw that out sideways with
a sort of sqwishing movement. You can sharpen up the profiles with a wooden
rib.
It is physically and visually stronger and because you started off the clay
in that direction it doesnt have the memory of standing up.
- also you can go back after a bit and throw them back down again if you
need to.
Pat Southwood.
______________________________________________________________________________
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
melpots2@visi.com
Ivor and Olive Lewis on wed 26 sep 07
Dear Fred Parker,=20
This is a prime example of what is usually termed "Clay Memory". By =
bending your clay you inducing a compressive stress on the underside and =
a tensile stress on the upper face. Removing water removes these =
stresses and the clay attempts to return to its original position.
In an early issue of Pottery Making Illustrated there is an article =
about making plates. This illustrates how to "Throw" a rim outwards from =
the "Gathering" you make after the "Well" has been extended then =
consolidated. The original motion of your fingers will shear the clay =
then form that rim by reverse extrusion, with your upper and lower =
fingers acting as an extrusion die. since all the forces are lateral =
there will be little vertical shrinkage and the rim will retain its =
original orientation.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Michael McDowell on wed 26 sep 07
Just an afterthought on the question regarding plate rims. All this advice
on evening out the rate of drying is certainly to the point. But I am
wondering if you have taken any of your plates through a glaze fire yet. You
may find that rims will flatten considerably if your clay is fired near
vitrification. Especially if they have the plastic memory of being formed to
a flatter profile. If the rims settle back in the glaze fire, then you
really have a non-problem.
Michael McDowell
Whatcom County, WA, USA
michael@mcdowellpottery.com
http://www.McDowellPottery.com
Allyson May on wed 26 sep 07
Hey Fred,
I'll throw in my two cents worth. I throw big plates (17" and up) with =
wide rims. I use plaster bats and leave them to dry until the end of =
the day. Before I leave the studio for dinner I return them to the =
wheel and flatten out the rim with a rib. Just before bed I come back =
to the studio and flatten them once more and then cover with plastic. I =
don't ever dry them on their rims but I do use Hardi board to dry them =
on after trimming. =20
Peace,
Allyson May
Stoney Creek Pottery
Bloomington, IN
AMay4@msn.com
Rogier Donker on wed 26 sep 07
Hey Fred...
First: are you throwing the plate on a plaster bat?
If so ,do not wire cut it but let it shrink away from the bat
(covered in plastic), may take 24 or more hours, but it WILL free
itself from the bat. If you do wire cut , allow a little extra
thickness in the bottom of the plate, because the tautly held wire
will always rise up in the center and inevitably cut off more clay
than you wanted to be cut... As for the rim turning up as it dries:
when you first turn the rim down, push it down just past
horizontal... it will dry into a 15-20 degree angle... at least mine
have for forty some years. Similarly one puts a teapot spout on the
teapot body at an angle, so when the thing dries the spout will be
straight and the teapot will pour properly....
Experience, experience, experience!
HPC! (That's "Happy Potting Continued"!)
Rogier
See us on the web at http://www.donkerstudio.org
Fred Parker on wed 26 sep 07
Hi John:
Thanks for the reply. I do throw on a plastic CI bat, which I have grown
to hate but have more of than anything else, and I have NOT been covering
the plates with plastic during their initial stage of drying. Usually, I
wait until they are leather hard, remove them from the bat, trim them and
then cover them with plastic, bottoms up. I do this because it speeds up
drying to the trim stage, but it might be better to slow down.
Fred Parker
On Tue, 25 Sep 2007 13:20:08 -0500, John Rodgers wrote:
>That is happening due to uneven drying from rim towards the center. u
>can reduce this tendency by covering the plate with plastic sheet and
>allow to dry more slowly. I have found this problem to be worse on
>plastic and similar bats. Switching to a plaster bat helped to alleviate
>the problem - not 100 percent, but significantly so. Between the plaster
>bat and the plastic sheet I have virtually no pulling of the rim as you
>describe. The plaster helps do some of the drying that usually takes
>place directly to the air - the latter inducing the pulling you desctibe.
>
>Regards,
>
>John Rodgers
>
>Fred Parker wrote:
>> I'm trying to learn how to throw plates. Either something weird is
>> happening or I am hallucinating.
>>
>> I throw the plate from a flattened ball of clay, develop a thicker ridge
>> on the outside of the roataing disk, raise this thickened ridge to 1"-
>> 1.5", clean up the plate bottom with a plastic rib, clean up the
exterior
>> base with a wood rib, then bend the plate's rim over to about a 15-20
>> degree angle (using a plastic rib with a wet sponge supporting
>> underneath. I wire the plate off holding the wire flat to the bat, then
>> set it aside to stiffen -- usually overnight. The next morning I remove
>> the plate and turn the bottom using a clay chuck.
>>
>> The problem is that the rim -- which I form to approximately 15 degrees
>> from horizontal -- pulls up to a 30-45 degree angle as the plate dries
to
>> leather hard. Is there any way to prevent this?
>>
>> Many thanks,
>>
>> Fred Parker
>>
>>
___________________________________________________________________________
___
>> 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
melpots2@visi.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
melpots2@visi.com
Eleanora Eden on wed 26 sep 07
Me three on this one....I flip them back and forth trying to get
an even rim without any flattening of the center.
Eleanora
>I'm with Marcia...flipping it over to dry more slowly
>by trapping moisture in does help eliminate the warping.
>However, there is a caveat that goes along with that...
>if your center is thin, you may get some "gravimetric distortion"
>(ie. slumping) of the center as it dries. I've found that leaving it
>for a day or two rim down, then flipping it back over and allowing
>it to dry fully was the trick that worked for me. YMMV of course.
>I dry on HardieBoard, not wood or plastic, if it matters.
>Best,
>Wayne Seidl
--
Bellows Falls Vermont
www.eleanoraeden.com
Marcia Selsor on wed 26 sep 07
Wayne,
If the center is soft I put a soft sponge to support the center..even
as I am trimming.
Lips will pull up as they dry and shrink...so keeping a bat on top
helps prevent that. As soon as the lip can support the weight of the
platter, I flip it sandwiched between two bats. Like Eleanor, I keep
flipping them back and forth, removing the bats to even the drying,
cover with bats to keep the lip flat, etc....they require baby sitting.
Marcia Selsor
http://marciaselsor.com
On Sep 26, 2007, at 10:57 AM, Eleanora Eden wrote:
> Me three on this one....I flip them back and forth trying to get
> an even rim without any flattening of the center.
>
> Eleanora
>
>
>> I'm with Marcia...flipping it over to dry more slowly
>> by trapping moisture in does help eliminate the warping.
>> However, there is a caveat that goes along with that...
>> if your center is thin, you may get some "gravimetric distortion"
>> (ie. slumping) of the center as it dries. I've found that leaving it
>> for a day or two rim down, then flipping it back over and allowing
>> it to dry fully was the trick that worked for me. YMMV of course.
>> I dry on HardieBoard, not wood or plastic, if it matters.
>> Best,
>> Wayne Seidl
>
> --
> Bellows Falls Vermont
> www.eleanoraeden.com
Joseph Herbert on wed 26 sep 07
Fred Parker wrote about the changes in angle of the rims of the plates he is
throwing.
Generally, this is caused by the shrinkage of the clay as it looses water.
The rim becomes dryer faster, becomes smaller, and so pulls toward the
center of the plate. Since the rim is attached to the rest of the plate,
the side comes up too. As others have noted, when the plate is entirely
dry, the rim will have flattened out to the nearly the original condition.
For long-time potters the changes in volume that accompany clay's journey
from material to object are sort of second nature. Clay shrinks about 15 -
17% from the plastic state to the final fired state. About half of this
occurs as the clay dries, a little more takes place when fired to porous
bisque, and the rest when the glaze fire vitrifies the material and
collapses the pores of the pot.
In beginning pottery classes the savvy teacher insists that the students put
their names on the first "keeper". The student is sure that this early
landmark in their progress toward a tea set will be so engrained in their
mind that no foul marking is requires for identification. I have seen such
objects sit on the bisque cart for weeks because the owner, glancing over
the cart, did not recognize the object and did not look for the initials or
name. What was the problem? Size. They usually exclaim that it was so
small they did not think it could possibly be theirs. To be fair, there is
usually a color change as well and that contributes to the confusion.
The differential shrinkage during drying has the possibility of wrecking a
pot. A wide, relatively thin bottom on a pot that is inverted to dry may
crack under the tension as the bottom shrinks and the foot ring and rim are
still damp. The problems are worse if there is a range of thicknesses in
the pot. I have a tendency to leave fairly large (thick) foot rings on pots
and if I am not careful about how rapidly a wide bottom dries, I am asking
for trouble. The difference in thickness of the bottom and that of the clay
surrounding it is enough to create problems. I have, of course, made this
mistake often enough that I make it much less frequently now. There seems
to be some power of two rule for simple errors. You make the mistake, darn,
you make it again, drat! Then time goes by, darn. Then twice as much time
goes by, Drat! Then twice as much as the last interval or four times as
long - darn, then twice again (or 8 times) - well. Then twice again - sighs.
We also, in our non-potting lives, don't think of shrinkage volumetrically;
linear shrinkage we kind of get but volume, not so much. Mostly because we
so rarely confront it. Writing this, I have been trying to think of an
example that doesn't have clay in it. Pattern makers for metal molds
confront this problem constantly. The patterns they make must leave a hole
in the mold that is the right size to produce the desired size object -
after the metal solidifies. They use "shrink rules" which are measuring
scales that are calibrated for different metal's shrinkage. A steel
shrinkage rules might have an 8% shrinkage factor so the scale would have
every thing 8% larger. The 12 inch shrink rule for 8% would actually be
12.96 inches long. The pattern maker makes all his measurements with this
scale and the pattern he makes is 8% larger in all directions.
Anyway, try tuning your awareness to how much clay things shrink during the
process. After a while, you will not think about it so much and fit your
work practices to keep this innate characteristic of the material from
causing you problems.
Joe
Joseph Herbert
Technical Writer
Irving, Texas
214-725-8305 (Cell)
Ron Roy on wed 26 sep 07
Hi Fred,
I make a lot of dinnerware with flat rims that I carved - and it was
important that they be fairly flat. To compound the problem I worked in
porcelain so - if I got them too flat they slumped in the firing.
First of all you have to understand - stretched clay shrinks more when
drying and firing than compressed clay. The way you are making those rims
stretches the clay a lot - recompress in from the edge to minimize that
problem. Leave the rims thicker than you want them - even where you have
recompressed them - for three reasons - you slow down the drying, you can
get then over on the rims sooner and you can trim them flatter later.
I throw the rims out rather than flatten them from the vertical - more
compression that way (but still recompress at the end) and I also had to
leave more clay under - near the body of the plate - like a flying buttress
- to prevent sagging of the rim during the firing.
Like everyone else says - dry your plates evenly - that means slowly for
most clays.
Trying to solve this problem with clays that have much more that 12%
overall shrinkage is going to be more difficult. Grog is going to help.
RR
>I'm trying to learn how to throw plates. Either something weird is
>happening or I am hallucinating.
>
>I throw the plate from a flattened ball of clay, develop a thicker ridge
>on the outside of the roataing disk, raise this thickened ridge to 1"-
>1.5", clean up the plate bottom with a plastic rib, clean up the exterior
>base with a wood rib, then bend the plate's rim over to about a 15-20
>degree angle (using a plastic rib with a wet sponge supporting
>underneath. I wire the plate off holding the wire flat to the bat, then
>set it aside to stiffen -- usually overnight. The next morning I remove
>the plate and turn the bottom using a clay chuck.
>
>The problem is that the rim -- which I form to approximately 15 degrees
>from horizontal -- pulls up to a 30-45 degree angle as the plate dries to
>leather hard. Is there any way to prevent this?
>
>Many thanks,
>
>Fred Parker
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Larry Kruzan on thu 27 sep 07
Prime example of working with the clay instead of forcing the clay into
submission. Have you ever noticed how much clay is like a wife? (I'll
pay for this one!)
Larry Kruzan (happily married for 30 years to a lady with a sense of humor)
Lost Creek Pottery
www.lostcreekpottery.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and Olive
Lewis
Sent: Wednesday, September 26, 2007 1:41 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: [CLAYART] Plate rim question
Dear Fred Parker,
This is a prime example of what is usually termed "Clay Memory". By bending
your clay you inducing a compressive stress on the underside and a tensile
stress on the upper face. Removing water removes these stresses and the clay
attempts to return to its original position.
In an early issue of Pottery Making Illustrated there is an article about
making plates. This illustrates how to "Throw" a rim outwards from the
"Gathering" you make after the "Well" has been extended then consolidated.
The original motion of your fingers will shear the clay then form that rim
by reverse extrusion, with your upper and lower fingers acting as an
extrusion die. since all the forces are lateral there will be little
vertical shrinkage and the rim will retain its original orientation.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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Fred Parker on thu 27 sep 07
On Tue, 25 Sep 2007 23:32:24 EDT, Clayart SCtag wrote:
Hi Meg:
DOn't know. Haven't glazed them yet, but the rim did settle somewhat
after the plates dried. We'll see...
Fred
>
>So, what angle is it after glaze firing? I assume you know there will be
>some drop during the firing[s].
>Meg
>
>
>
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Lois Aronow on thu 27 sep 07
If you're throwing with grolleg porcelain, this is definitely the case.
I throw my rims a little level, planning for them to rise and settle.
----- Original Message -----
From: Fred Parker
Date: Thursday, September 27, 2007 9:55 am
Subject: Re: Plate rim question
To: CLAYART@LSV.CERAMICS.ORG
> On Tue, 25 Sep 2007 23:32:24 EDT, Clayart SCtag
> wrote:
>
>
> Hi Meg:
>
> DOn't know. Haven't glazed them yet, but the rim did settle somewhat
> after the plates dried. We'll see...
>
> Fred
>
> >
> >So, what angle is it after glaze firing? I assume you know there
> will be
> >some drop during the firing[s].
> >Meg
> >
> >
> >
> >************************************** See what's new at
> http://www.aol.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
> melpots2@visi.com
>
>
______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
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>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
Miles G. Smith on fri 28 sep 07
Lois:
Where can I purchase grolleg porcelain?
Miles Smith Pottery
----- Original Message -----
From: "Lois Aronow"
To:
Sent: Thursday, September 27, 2007 11:11 AM
Subject: Re: Plate rim question
> If you're throwing with grolleg porcelain, this is definitely the case.
> I throw my rims a little level, planning for them to rise and settle.
>
> ----- Original Message -----
> From: Fred Parker
> Date: Thursday, September 27, 2007 9:55 am
> Subject: Re: Plate rim question
> To: CLAYART@LSV.CERAMICS.ORG
>
> > On Tue, 25 Sep 2007 23:32:24 EDT, Clayart SCtag
> > wrote:
> >
> >
> > Hi Meg:
> >
> > DOn't know. Haven't glazed them yet, but the rim did settle somewhat
> > after the plates dried. We'll see...
> >
> > Fred
> >
> > >
> > >So, what angle is it after glaze firing? I assume you know there
> > will be
> > >some drop during the firing[s].
> > >Meg
> > >
> > >
> > >
> > >************************************** See what's new at
> > http://www.aol.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
> > melpots2@visi.com
> >
> >
>
____________________________________________________________________________
__
> > Send postings to clayart@lsv.ceramics.org
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> > melpots2@visi.com
>
>
____________________________________________________________________________
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Lois Ruben Aronow on sat 29 sep 07
Most clay manufacturers sell bagged grolleg - Standard 356 (^6) or 257
(^10). I don't know what the other manufacturers call theirs, but you can
easily ask. In the clay descriptions, it is also refered to a "english
kaolin".
A true grolleg pocelain will contain no ball clay, making it a challenge to
work with (but worth it). If you are making your own clay body or slip, you
can buy Grolleg in powder. Look under the "kaolin" section of your ceramic
supply catalog.
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of
> Miles G. Smith
> Sent: Friday, September 28, 2007 10:58 AM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Plate rim question
>
> Lois:
>
> Where can I purchase grolleg porcelain?
>
> Miles Smith Pottery
>
>
>
> ----- Original Message -----
> From: "Lois Aronow"
> To:
> Sent: Thursday, September 27, 2007 11:11 AM
> Subject: Re: Plate rim question
>
>
> > If you're throwing with grolleg porcelain, this is
> definitely the case.
> > I throw my rims a little level, planning for them to rise
> and settle.
> >
> > ----- Original Message -----
> > From: Fred Parker
> > Date: Thursday, September 27, 2007 9:55 am
> > Subject: Re: Plate rim question
> > To: CLAYART@LSV.CERAMICS.ORG
> >
> > > On Tue, 25 Sep 2007 23:32:24 EDT, Clayart SCtag
>
> > > wrote:
> > >
> > >
> > > Hi Meg:
> > >
> > > DOn't know. Haven't glazed them yet, but the rim did settle
> > > somewhat after the plates dried. We'll see...
> > >
> > > Fred
> > >
> > > >
> > > >So, what angle is it after glaze firing? I assume you know there
> > > will be
> > > >some drop during the firing[s].
> > > >Meg
> > > >
> > > >
> > > >
> > > >************************************** See what's new at
> > > http://www.aol.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
> > > melpots2@visi.com
> > >
> > >
> >
> ______________________________________________________________
> ______________
> __
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> >
> >
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> >
>
> ______________________________________________________________
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