pdp1@EARTHLINK.NET on tue 21 jun 05
Hi Sincultura,
It it were me...(and I used to throw way 'thin' for some things...allways
smallish things...)
On reflection, I would try experimenting with not only having nice, soft,
friendly Clay of course, but...
With adding oils or Soaps or other things to make the Clay more slippery and
to hold together better.
I do not know what some good practices would be, since I did not try any
additives when I was throwing, but I would sure as heck find out now, if I
were back at it and wanting to do way 'thin' things...
Pee in the Clay, and throw organics in there and let it fester and so
on...would be one old time thing to try for enhanced plascticity. Vinegar in
the Clay...Fruit Juices...try things, see what happens. Let it age a month
or two...two anyway, or three even...
Thats where I'd begin...
Find some pragmatic plasticity enhancing methods which do not take from the
strength at the same time.
The less Water the better...or, to get friendly and very plasctic Clay which
one may throw kinda dense or firm...
Phil
el ve
----- Original Message -----
From: "Sincultura 13"
> I started throwing narrow altered 12"- 14" tall vases... I'm happy with
the form but I think they are a bit on the heavy side... Since I alter them
before they reach leather hard I can't trim them.
>
> How thick is too thick for a thrown pot wall?
>
> I was wondering if somebody could help me out with some tips on how to
throw thinner tall pots?
>
> thanks in advance,
>
> Sincultura
>
> __________________________________________________
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> Send postings to clayart@lsv.ceramics.org
>
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>
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melpots@pclink.com.
Sincultura 13 on tue 21 jun 05
I started throwing narrow altered 12"- 14" tall vases... I'm happy with the form but I think they are a bit on the heavy side... Since I alter them before they reach leather hard I can't trim them.
How thick is too thick for a thrown pot wall?
I was wondering if somebody could help me out with some tips on how to throw thinner tall pots?
thanks in advance,
Sincultura
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Antoinette Badenhorst on wed 22 jun 05
Sincultura, my experience tells me that anything that weighs heavier =
than
what one's eye tells you, is too heavy. My advice there would be to ask =
your
friends and family to look at the pot and then pick it up. If it is =
heavier
than they expected it to be, it is to heavy. Of cause the opposite is =
also
true; if it is lighter that what the eye weighs it, it is also wrong. To
throw tall cilinders and thin it enough at the bottom part of the wall =
is
difficult, particularly if you are a beginner. A tip that someone gave =
me
long ago was to create a grove right at the bottom where the wall reach =
the
wheelhead. Instead of pinching the clay thinner, push the wall upward =
with
your finger, knuckle or handpalm, while the inside hand guides. From =
there
on you can use plastic kidneys to help you thin the clay till the =
desired
thickness. The kidneys also take slurry away that weakens the walls of a
pot. If you still have access clay, you can remove that with a surform =
blade
after you altered your pot. Have fun.
Antoinette Badenhorst
105 Westwood Circle
Saltillo MS, 38866
www.clayandcanvas.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Sincultura =
13
Sent: Tuesday, June 21, 2005 7:46 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Need throwing thin tips...
I started throwing narrow altered 12"- 14" tall vases... I'm happy with =
the
form but I think they are a bit on the heavy side... Since I alter them
before they reach leather hard I can't trim them.
How thick is too thick for a thrown pot wall?
I was wondering if somebody could help me out with some tips on how to =
throw
thinner tall pots?
thanks in advance,
Sincultura
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.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
melpots@pclink.com.
Wayne Seidl on wed 22 jun 05
Dave:
While I do not pee in my porcelain, it does work to age it.
Then again, so do other organic things.
Remember that most humans (98% I think) have sterile urine.
Ask a doctor.
It's all in what you're comfortable with...and what peed in it
before it got to you. Think clay is sterile?
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of David
Guy Fetzer
Sent: Wednesday, June 22, 2005 5:50 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Need throwing thin tips...
Phil:
You can't be serious about "Pee in the clay"?
Cheers,
Dave
----- Original Message -----
From:
To:
Sent: Tuesday, June 21, 2005 11:48 PM
Subject: Re: Need throwing thin tips...
> Hi Sincultura,
>
>
> It it were me...
snip
> Pee in the Clay, and throw organics in there and let it fester and
so
Mike Gordon on wed 22 jun 05
On Jun 22, 2005, at 2:49 PM, David Guy Fetzer wrote:
> Phil:
>
> You can't be serious about "Pee in the clay"?
> \David,
I don't know if this is potters lore or not but the story goes that a
potter or potters in Japan dug and stored 3-4 tons of clay for their
son so it would be properly aged by the time he started throwing pot on
his own. The women did all the peeing and foot wedging. Somebody told
me that 40 yrs ago while in college. Mike Gordon
Elizabeth Priddy on wed 22 jun 05
Get as much height as you can and as thin as you can.
Then leave it on the wheel in place for about 30 minutes. It
will set up a bit. then make a few more passes to thin the walls.
Thin the top half of the column first and then the bottom, blending
it into the top. This reduces tortion as you pull through to the top with
only enough pressure to straighten it up.
Let it set for another hour.
Wheel trim it with a loop tool and then smooth the raised tooth with a
rubber rib.
this should get you to about a 1/4 inch. Get a thumb tack and measure
the pot all the way up, thinning again as necessary.
Also, start with very wet, fluid clay. You will throw thinner and faster.
Practice this technique on 8 inch cylinders for about ten pots. (use the
forms for sketches or minis of your larger pots).
Then go for it.
E
Sincultura 13 wrote:
I started throwing narrow altered 12"- 14" tall vases... I'm happy with the form but I think they are a bit on the heavy side... Since I alter them before they reach leather hard I can't trim them.
How thick is too thick for a thrown pot wall?
I was wondering if somebody could help me out with some tips on how to throw thinner tall pots?
thanks in advance,
Sincultura
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.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 melpots@pclink.com.
Elizabeth Priddy*
252-504-2622
1273 Hwy 101
Beaufort, NC 28516
http://www.elizabethpriddy.com
*If you are an extra-sensitive or easily-offended type:
Remember that what I say is obviously just my opinion based
on my experiences and that I, like most people, don't go around
intending to step on toes and make folks cry. Take it with a
grain of salt and move along, there are others waiting to
give me grief because of their own buttons I inadvertently
pushed...
---------------------------------
Do you Yahoo!?
Yahoo! Mail - Find what you need with new enhanced search. Learn more.
Eric Hansen on wed 22 jun 05
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Sincultura =3D
13
Sent: Tuesday, June 21, 2005 7:46 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Need throwing thin tips...
I started throwing narrow altered 12"- 14" tall vases... I'm happy with =3D
the
form but I think they are a bit on the heavy side... Since I alter them
before they reach leather hard I can't trim them.
How thick is too thick for a thrown pot wall?
I was wondering if somebody could help me out with some tips on how to =3D
throw
thinner tall pots?
thanks in advance,
Sincultura
--=20
_______________________________________________
NEW! Lycos Dating Search. The only place to search multiple dating sites at=
once.
http://datingsearch.lycos.com
Eric Hansen on wed 22 jun 05
Sincultura: My little brother said it "keep it dry and throw from the insid=
e"
I had a teacher, and Alfred MFA grad, an associate Professor, who confided =
in me that whenever he threw he had these deep throwing rings that he then =
had to hide by ribbing the outside of the pot and pushing them to the insid=
e. He eventually quit working on the wheel because he never could get rid o=
f the deep gouges. I wondered about this for a long time and experimented w=
ith several different things he could have done. Throwing rings make the po=
t stronger. If you take a rib and a metal scraper and do the inside and out=
side and remove the rings you get weaker walls (easier to alter?). So one w=
ay to throw thinner is to keep the throwing rings in there till your last p=
ull and shape. - anyway this teacher used his fingertips exclusively. So I =
was checking out what I did differently? and noticed I used my last finger =
joint as though it were a rib almost parallel to the wall. So I never encou=
ntered his problem. In Kansas the clay was always drying out - your fingers=
got strong. Here in Oregon my clay sits and gets more and more moist. The =
last year when I revived my throwing - I have never used so much soggy clay=
; but I discovered that I can throw that stuff too - by positioning my fing=
ers more like an extrusion process, less digging into the clay that what I =
used to do. So now I do that all the time and it works better. A subtle imp=
rovement. Over the years I've tried to throw deep and wide and thin, virtuo=
so throwing , tried and tried. Now I don't bother. I just make really heavy=
pots "and go on down the road" I looked at some ancient Greek pots they m=
ade on the wheel - like a 1/16" thick - amazing. It can be done alright.
Keep the clay fairly dry and make sure you hands are well lubricated in slo=
p. It makes the clay stronger and you can thin the walls more. Getting it t=
oo wet and it gets weak. This potter out here was watching me one day and s=
aid he had never seen these hand positions before - what can I say? That is=
what I was shown. I watch potters here and add theirs to mine - it is like=
a language you learn. Then there are righthanded potters throwing clockwis=
e. My brother is lefthanded and throws counterclockwise. I'm right handed a=
nd throw counterclockwise. Talk about hand positions and variations... I th=
ink you are doing the right thing by throwing thinner rather than trimming.=
I try not to trim. Of course there is nothing WRONG with it but I would ra=
ther limit the trimming.
H A M B O N E
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Sincultura =3D
13
Sent: Tuesday, June 21, 2005 7:46 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Need throwing thin tips...
I started throwing narrow altered 12"- 14" tall vases... I'm happy with =3D
the
form but I think they are a bit on the heavy side... Since I alter them
before they reach leather hard I can't trim them.
How thick is too thick for a thrown pot wall?
I was wondering if somebody could help me out with some tips on how to =3D
throw
thinner tall pots?
thanks in advance,
Sincultura
--=20
_______________________________________________
NEW! Lycos Dating Search. The only place to search multiple dating sites at=
once.
http://datingsearch.lycos.com
Wes Rolley on wed 22 jun 05
Elizabeth wrote:
> Then leave it on the wheel in place for about 30 minutes. It will set u=
p a bit. then make a few more passes to thin the walls.
>=20
> Thin the top half of the column first and then the bottom, blending it =
into the top. This reduces tortion as you pull through to the top with on=
ly enough pressure to straighten it up.
>=20
> Let it set for another hour.=20
This is not meant as a criticism of Elizabeth especially. She generally =
gives
good advice and this would work. But there has to be a better answer tha=
n this.
Having only one wheel, to give up the use of that wheel for an hour and =
a half
when the time for throwing is limited anyway just does not make good sens=
e.
Yes, I know that with practice, the 90 minutes of waiting for 5 minutes o=
f
throwing will get shorter. But still, there is a rhythm to working that =
just
got broken into little pieces like Humpty Dumpty.
I write in this mode because I need the same tips for my own work.
Wes
--=20
"I find I have a great lot to learn =E2=80=93 or unlearn. I seem to know =
far too much
and this knowledge obscures the really significant facts, but I am gettin=
g on."
-- Charles Rennie Mackintosh
Wesley C. Rolley
17211 Quail Court
Morgan Hill, CA 95037
(408)778-3024
http://www.refpub.com/
Lee Love on wed 22 jun 05
You can either use the "upside down first" John Reeve throwing method or
do coil and paddle. Both of these methods will make very thin pots.
Reeve's method allows you to throw a bottom thinner than the clay is
structurally able to bear when soft enough to throw. The bottom dries
before you flip the pot over to throw the top.
--
Lee Love
in Mashiko, Japan http://mashiko.org
http://hankos.blogspot.com/ Visual Bookmarks
http://ikiru.blogspot.com/ Zen and Craft
About the best pots:
"They are not necessarily amenable to intellectual analysis,
and, in fact, that analysis can destroy a person's real
appreciation and understanding of a piece."
-- Warren MacKenzie
Mike Gordon on wed 22 jun 05
On Jun 22, 2005, at 5:09 AM, Elizabeth Priddy wrote:
> Get as much height as you can and as thin as you can.
>
> Then leave it on the wheel in place for about 30 minutes. It
> will set up a bit. then make a few more passes to thin the walls.
> __________________________________________________
> I agree with what Elizabeth says except - - After throwing it as
> tall as possible the first time --- I always wash and dry my hands and
> with a metal rib, I rib off all the wet clay that has accumulated from
> the first attempt. This wet clay will migrate into the dryer clay wall
> beneath it over time, osmosis, I think it is called, then let it sit
> with the wheel spinning slow, eliminates room drafts drying just one
> side. Mike Gordon
David Guy Fetzer on wed 22 jun 05
Phil:
You can't be serious about "Pee in the clay"?
Cheers,
Dave
----- Original Message -----
From:
To:
Sent: Tuesday, June 21, 2005 11:48 PM
Subject: Re: Need throwing thin tips...
> Hi Sincultura,
>
>
> It it were me...(and I used to throw way 'thin' for some things...allways
> smallish things...)
>
> On reflection, I would try experimenting with not only having nice, soft,
> friendly Clay of course, but...
>
> With adding oils or Soaps or other things to make the Clay more slippery
> and
> to hold together better.
>
> I do not know what some good practices would be, since I did not try any
> additives when I was throwing, but I would sure as heck find out now, if I
> were back at it and wanting to do way 'thin' things...
>
> Pee in the Clay, and throw organics in there and let it fester and so
> on...would be one old time thing to try for enhanced plascticity. Vinegar
> in
> the Clay...Fruit Juices...try things, see what happens. Let it age a month
> or two...two anyway, or three even...
>
> Thats where I'd begin...
>
> Find some pragmatic plasticity enhancing methods which do not take from
> the
> strength at the same time.
>
> The less Water the better...or, to get friendly and very plasctic Clay
> which
> one may throw kinda dense or firm...
>
>
>
> Phil
> el ve
>
> ----- Original Message -----
> From: "Sincultura 13"
>
>
>> I started throwing narrow altered 12"- 14" tall vases... I'm happy with
> the form but I think they are a bit on the heavy side... Since I alter
> them
> before they reach leather hard I can't trim them.
>>
>> How thick is too thick for a thrown pot wall?
>>
>> I was wondering if somebody could help me out with some tips on how to
> throw thinner tall pots?
>>
>> thanks in advance,
>>
>> Sincultura
>>
>> __________________________________________________
>> Do You Yahoo!?
>> Tired of spam? Yahoo! Mail has the best spam protection around
>> http://mail.yahoo.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
> melpots@pclink.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
> melpots@pclink.com.
>
Ben Shelton on wed 22 jun 05
Well,
Thinner and taller were always like bigger and better when I was learning to
throw. I watched Randy Brodnax throw 25 lbs of clay so tall, he had to wash
off his arm pits after. The final pots were big and round and got thin by
the ewya he stretched them outward with a rib inside and out.
This isn't gonna work for you since you aren't making big round forms, you
said you were making tall thin forms.
Here is what I would do.
Start with 10 balls of clay the weight as what you are using now.
I never liked clay that was really soft because it won't stand up.
Learn "The grip" or "The Hungarian Claw" whatever you want to call it. For
your first pull, sponge in right hand, make a letter "C" with the left.
Place the right against the left for bracing. Use this letter "C" as a claw
to make your first pull. I run the wheel kinda fast and let the water flow
from the sponge on the first couple of pulls. If you are dragging or
sticking on the clay, add water. (Of course when you have made your first
couple of pulls, get the water out of the bottom to avoid cracks)
This was the biggest benefit to my learning how to throw taller and thinner
and faster. Someone jokingly called it the "Hungarian Claw" or something so
that kinda stuck in my mind. Whatever you call it, at 12 inches tall you
should try to make half that height on the first pull and it should only
take about 30 seconds. Three pulls should only take a couple of minutes and
you should be at 75% to 90% of your full height.
Now, if you are not getting thin enough to satisfy you, start making your
clay balls smaller when you start. See how little clay you can use to get
the same height.
As an exercise, use 2 pound balls, open each to the same width and pull as
tall, thin and fast as possible. wire cut from top to bottom and look at the
wall thickness. You'll be able to see how evenly you are pulling and judge
the thickness as well. Great warm up excercise as well.
Hope this helps,
Ben
Craig Clark on thu 23 jun 05
>How thick is too thick for a thrown pot wall?
>
>I was wondering if somebody could help me out with some tips on how to =
>throw
>thinner tall pots?
>
>thanks in advance,
>
>Sincultura
>
>
>
This is a question that probably has as many different answers as
there are potters willing to give them. I think the thickness of the
wall of a pot ought to be determined by the purpose of the piece and
whether or not the potter wants the the physical weight of the piece and
the visual weigth of the piece to be in agreement. This is something
that the potter gets a handle on over years of exploring a particular
form. Admittedly, what I have just said doesn't really mean
doodly-squat. I guess it's up to the potter and what she or he is happy
with in the end.
As to throwing taller/thinner pots, to add to what has already been
said recently..........two more things that may or may not have been
mentioned. One, after you get a goodly sized cylinder up on the first
pull or two do something that I learned from Robert Pipenburg at a
workshop. He went about half way down the cylinder and then made another
coupla pulling passes to the top. Then he went all the way down to the
bottom and did another coupla pulls up to even up the form. This gave
him some pretty good height.
Another thing that has worked for me recently is to first think
about the idea of lifting rather than pulling. You want to lift the clay
up into the air. Stay under the shelf of clay and lift upward and
inward. Focus on this. Breath through it and concentrate. There is a
real Zen to it. Use as little compressive force between your juxtaposed
fingers, knuckles or whatever, as you are able. The idea is to try and
not squeeze the clay. This just results in more friction which is not
benifical to this particular cause.
Hope this helps
Craig Dunn CLark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
Vince Pitelka on thu 23 jun 05
Eric said:
"Throwing rings make the pot stronger. If you take a rib and a metal scraper
and do the inside and outside and remove the rings you get weaker walls
(easier to alter?)."
Eric -
I am curious about the statement above, and would love to hear your
theories. Compressing the clay with ribs during throwing helps reduce
spiral grain structure. Thus it seems the pot would be as strong or
stronger after the throwing rings are removed.
- 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/
Bob Hanlin on thu 23 jun 05
In one of the magazines...I think it was CM, they had some drawings showing...
First, pull up a cylinder as thin as you can, then
Pull up just the top half....and then go down and get the bottom half....then
Pull up just the top third...and then the middle third....and then the bottom third
Each time you pull up a fraction of the cyliinder, you continue to the top of the cylinder so's you keep controf the bugger.
I've tried this and it works for me....
so,,,give it a try
Des & Jan Howard on thu 23 jun 05
Dave
As the main ingredient for our clay body comes from a spot used as a
sheep camp I guess there is pee in it.
At least it don't bob around in the blunger like the other organic
material :-)
Des
David Guy Fetzer wrote:
> Phil:
>
> You can't be serious about "Pee in the clay"?
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
Angela Davis on thu 23 jun 05
Phil wrote:
"Pee in the Clay, and throw organics in there and let it fester and so
on...would be one old time thing to try for enhanced plascticity. Vinegar
in
the Clay...Fruit Juices...try things, see what happens. Let it age a month
or two...two anyway, or three even..."
Angela Davis says:
From the sound of this I believe Phil has been getting under the table
advice from
Mel and Tony C!
And no Dave he isn't kidding, I have read this very addition for quickly
ageing
clay in several places.
My preferred method is to use wine that has proven
undrinkable, in other words I using something that just tastes like pee.
----- Original Message -----
From: "David Guy Fetzer"
To:
Sent: Wednesday, June 22, 2005 5:49 PM
Subject: Re: Need throwing thin tips...
> Phil:
>
> You can't be serious about "Pee in the clay"?
>
> Cheers,
>
> Dave
Earl Brunner on thu 23 jun 05
And you know this because........?????
Earl Brunner
Las Vegas, NV
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Angela Davis
Sent: Thursday, June 23, 2005 7:42 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Need throwing thin tips...
Angela Davis says:
My preferred method is to use wine that has proven
undrinkable, in other words I using something that just tastes like pee.
John Jensen on fri 24 jun 05
I agree with Vince here, both for his reason and for another. It seems =
to me
that like a chain with its weakest link, the sides of the pot are only =
as
strong as the weakest point. With the sides undulating in and out and =
with
varying thickness the sides will often collapse at a weak point. By =
evening
the sides out with a rib the thickness of the wall is uniform, =
eliminating
the possibility of a thin/weak point, and I believe the architecture of =
the
sides is improved with the removal of the undulations. That said, I =
like to
throw as thinly as I can and yet keep natural looking throwing lines.
John Jensen, Mudbug Pottery
John Jensen@mudbugpottery.com
http://www.toadhouse.com www://www.mudbugpottery.com
Eric said:
"Throwing rings make the pot stronger. If you take a rib and a metal =
scraper
and do the inside and outside and remove the rings you get weaker walls
(easier to alter?)."
>Vince said:
Eric -
I am curious about the statement above, and would love to hear your
theories. Compressing the clay with ribs during throwing helps reduce
spiral grain structure. Thus it seems the pot would be as strong or
stronger after the throwing rings are removed.
- Vince
Randall Moody on fri 24 jun 05
I usually throw tall (18"x6-8") cylinders on a bat then set them aside
to stiffen. I have marked my bats and wheelhead so that when I return
the bat they will be in the same orientation on the wheel as when I
first threw the cylinder. I have found that this helps me since I do
not throw directly dead on center. I think how thin the pot is, to a
point, irrelevant. If the pot looks like it should weigh five pounds
then it should.
I also agree that the use of the pot is important in determining the
thickness. All of the bowls I have thrown for use in our kitchen tend
to be a little thicker than a purely decorative bowl I would throw
because I know how much of abuse they are going to get when we are
nogging eggs or the like. The vases I throw to be turned into lamps I
make a little heavier than normal so that they will not be easily
knocked over. (My 22 pound cat taught me this.) The only problem I
have found is that after throwing lamp vases I am finding it hard to
throw thinner.
Eric Hansen on sat 25 jun 05
Vince: I think what I am trying to say is that in working with wet clay on =
the wheel, you can throw larger, thinner, more risky, if the throwing rings=
are left intact until the final stages of the work. My hands are my favor=
ite tools and I will try to do most of it with just them if I can. With the=
exception of compressing the bottom of the piece; which obviously is done =
exerting pressure with a flat rib against the bottom of the pot while the p=
ot is on the firm surface of the wheel head & I will then compress the othe=
r side of the bottom after I trim it. I know from experience that if I want=
a piece to slump, which is a feature that really turns me on :) the best w=
ay to get it is by getting rid of the throwing rings inside and out with th=
e ribs and then placing the metal scraper almost parallel to the pot with t=
he metal scraper smoothing the surface and bringing the colloidal particles=
to the surface. This has the effect of wetting the surface, which lends to=
other tactile surface effects, but that is not the reason for it slumping.=
The reason is that the corrugation of the surface has been removed. I woul=
d compare it to the case of corrugated cardboard. The the shape is easier t=
o alter, the clay tends to be more willing to loose it's concentic orientat=
ion. But I'm not a throwing guru I am still in my first few tons of clay an=
d I'm open to ideas. Compression with a rib may make the wet clay walls str=
onger, but if it is only fingers on the opposite side it won't be too much =
more comressed than what the fingers do. Different than when compressing th=
e bottom or compressing after triming where there is positive resistance. T=
he happy medium for me is to compress with the wooden rib, like you suggest=
, but leave the marks in. I read it as a softer, warmer, more friendly, and=
craft-suggestive look that I like in finished pieces. The actual strength =
of fired wares comes mostly from shape, design, materials, correct firing, =
proper glazing, and what not. Does this make sence? What do you think?
E R I C " H A M B O N E " H A N S E N
k a n s a s p o t t e r=20
Eric said:
"Throwing rings make the pot stronger. If you take a rib and a metal scrape=
r and do the inside and outside and remove the rings you get weaker walls (=
easier to alter?)."
Eric -
I am curious about the statement above, and would love to hear your
theories. Compressing the clay with ribs during throwing helps reduce
spiral grain structure. Thus it seems the pot would be as strong or
stronger after the throwing rings are removed.
- Vince
--=20
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Elizabeth Priddy on sat 25 jun 05
How those this theory hold up to corrugated cardboard?
Do the same mechanical engineering principles that make
corrugating cardboard stronger than flat cardboard apply to
fired clay?
I know it can be weaker when it is wet, but it seems
to be true that if you made sure that the thinnest spot is still
thick enough to be stable, then the work with undulating lines
would be structurally stronger than a flat wall.
Any engineers with ideas?
John Jensen wrote:
I agree with Vince here, both for his reason and for another. It seems to me
that like a chain with its weakest link, the sides of the pot are only as
strong as the weakest point. With the sides undulating in and out and with
varying thickness the sides will often collapse at a weak point. By evening
the sides out with a rib the thickness of the wall is uniform, eliminating
the possibility of a thin/weak point, and I believe the architecture of the
sides is improved with the removal of the undulations. That said, I like to
throw as thinly as I can and yet keep natural looking throwing lines.
Elizabeth Priddy*
252-504-2622
1273 Hwy 101
Beaufort, NC 28516
http://www.elizabethpriddy.com
*If you are an extra-sensitive or easily-offended type:
Remember that what I say is obviously just my opinion based
on my experiences and that I, like most people, don't go around
intending to step on toes and make folks cry. Take it with a
grain of salt and move along, there are others waiting to
give me grief because of their own buttons I inadvertently
pushed...
---------------------------------
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Vince Pitelka on sun 26 jun 05
> How those this theory hold up to corrugated cardboard?
> Do the same mechanical engineering principles that make
> corrugating cardboard stronger than flat cardboard apply to
> fired clay?
Elizabeth -
It's an interesting thought, but corrugated cardboard is a completely
different animal, and it's strength is derived from the "honeycomb" effect -
the fact that there is a zig-zag layer in the center, with a flat layer
laminated to either side. It's like the structural integrity of an "I"
beam - strengthened by the horizontal portions above and below the vertical
portion - each "wall" reinforces the adjacent walls, by virtue of the
"boxed" construction, and the same is true of corrugated cardboard. The
throwing ridges on a wet thrown pot are not at all similar, and in thrown
forms the strongest wall seems to be one that has been compressed with ribs.
I've been thinking about this, and cannot imagine any way in which the
throwing ridges would offer any structural advantage.
- 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/
John Jensen on sun 26 jun 05
Elizabeth;
Of course the difference with cardboard is that the "wavey" part is
sandwiched between two smooth even layers. There is a different sort of
geometry working there. Take the smooth outer layers of the corrugated
cardboard off and see how strong the "wavey" part is.
Sure, if you made the thin part thick enough to stand up then the thick =
part
would add strength. But that isn't really the point. The point I would
make is: Given an average thickness of a certain amount, a wall of =
varying
thickness will have some points thinner (and weaker) than the average. =
This
weak point us where the wall is likely to collapse, when and if it does.
I don't think you have to be an engineer to get this.
John Jensen, Mudbug Pottery
John Jensen@mudbugpottery.com
http://www.toadhouse.com www://www.mudbugpottery.com
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Elizabeth
Priddy
How those this theory hold up to corrugated cardboard?
Do the same mechanical engineering principles that make
corrugating cardboard stronger than flat cardboard apply to
fired clay?
I know it can be weaker when it is wet, but it seems
to be true that if you made sure that the thinnest spot is still
thick enough to be stable, then the work with undulating lines
would be structurally stronger than a flat wall.
Any engineers with ideas?
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