claybair on thu 27 oct 05
Tamara,
My first tile project produced many warped tiles in spite
of being very careful with them.
Finally it dawned on me that running a wire under them
to remove them from the block was a big mistake.
My tiles were small about 3" x 3" and about
1/4" thick. When I eliminated the wire & used paper the warping stopped.
It took quite a while to figure out what I was doing wrong.
There may be other reasons your platter warped but I know this was
an issue for me.
Gayle Bair
Bainbridge Island, WA
Tucson, AZ
http://claybair.com
-----Original Message-----
From: Tamara Petty
I'm a sculptor and not a potter (would love to learn the art of pottery too
:-) ) but I recently helped a friend to make a fish platter. We rolled it
out with a rolling pin - don't have a slab roller. :-( And it looked
great at the beginning but now after a few days of drying the center area
has risen quite a bit. The perimeter of the platter is flat on the table
but the center area is bowed up.
We used a wire to release the clay from the table after rolling it out and
shaping it and then put it on a paper bag so that it could shrink without
cracking. We put a piece of plastic over it to help it slowly dry. I was
wondering if I should put a weight, like a book, on it in the middle the
next time I want to make a platter; so that it doesn't want to warp upwards.
Does anyone have any suggestions as to how to keep a platter, 10" X 17" from
warping?
Here is a link to the picture of the platter...you might be able to see a
little bit from the picture how it has pulled up in the middle....
http://pg.photos.yahoo.com/ph/tamaron2@sbcglobal.net/detail?.dir=3123&.dnm=f
dad.jpg&.src=ph
Thanks so much for your help,
Tamara Petty
Northern California
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dannon rhudy on thu 27 oct 05
Tamara, warping of such forms is caused by uneven
drying. Generally, the rim will dry faster than the
center, and the rim will shrink. If it shrinks before the
center does, it must (and does) deform the center of
the piece, by bowing it. There are ways to prevent
this. You can completely wax the rim of the piece,
to slow its drying. You can wrap the rim carefully
in plastic wrap. You can put the piece upside down
on a piece of drywall, with another piece of drywall
on top, and this may even the drying, but won't always.
You should also make sure that your claybody is not
one prone to warp excessively. Some do.
regards
Dannon Rhudy
---
---
Tamara Petty on thu 27 oct 05
Thank you Anne for your advice. I think that the wire did come up in the center a bit so that's probably what helped to contribute to it warping. Also, I didn't roll it in both directions and I didn't compress it with a wooden rib. I learned so much from you! Thanks so much. I'll be anxious to try another one and see if I can get the hang of it.
I'll send pictures of the completed project. It's my friend, Cathy's project that I'm helping her to do. She's not played with clay since 7th grade! (she's 45 now :-)
I just love all of your (the potters) wonderful glazes and beautiful work. I'm using only commercial glazes right now and have the full line of everything Duncan and Mayco has to offer. I do have some ingredients to mix my own glazes but was kind of scared off by the danger factor of working with toxic things.
Here is my latest sculpture. I call her "Frontier Woman". I hope to maybe sell something one day. :-D
http://www.wetcanvas.com/forums/showthread.php?t=291002
You said to work on a "bat/board"....do you mean simply a flat surface? Wasn't sure of what that terminology means... Green behind the ears I guess. :-(
Tamara Petty
Northern California
hey tamara..
I like the fish design on that platter..looks great :)
Its really hard to get an even thickness consistency on a slab that big
using a rolling pin. The eveness will affect how your slab dries. ...as
would using a wire to cut the slab off the table. Often when you use a wire
like that (even when cutting a pot off a wheelhead) especially over a wide
expanse, the wire does not cut straight across, it kinda bows up in the
middle. might account for why the middle of the slab is drying out faster
and thus bowing up.
Maybe next time when you roll out the slab do it on newspaper. as the slab
gets bigger, you will need to lift it up and get it unstuck from the paper,
then you can continue rolling.. but it wont stick to your surface which is
impt.
another thing you can do is sprinkle some ball clay on your surface of the
rolling pin and table (kinda like you would with flour and dough). also,
when you roll it out, you want to make sure you roll in all directions which
helps prevent warpage.
I make 15" wide raku tiles and after i have my slab, i take the straight
edge of a wooden rib and use it to compress further...again in all
directions. I usually use that blue insulation board to dry the slabs on
then drape with plastic. i dont have too much warping usually.
slow even drying is essential.
oh yes.. dont forget clay has a memory, so work on a bat/board.
well best of luck. would love to see the final result :)
anne
>From: Tamara Petty
>Reply-To: Clayart
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Warping of a platter
>Date: Thu, 27 Oct 2005 11:55:24 -0700
>
>Hi Everyone!
>
>Been learning so much from reading the mail that goes to the list! :-D
>
>I'm a sculptor and not a potter (would love to learn the art of pottery too
>:-) ) but I recently helped a friend to make a fish platter. We rolled
>it out with a rolling pin - don't have a slab roller. :-( And it looked
>great at the beginning but now after a few days of drying the center area
>has risen quite a bit. The perimeter of the platter is flat on the table
>but the center area is bowed up.
>
>We used a wire to release the clay from the table after rolling it out and
>shaping it and then put it on a paper bag so that it could shrink without
>cracking. We put a piece of plastic over it to help it slowly dry. I was
>wondering if I should put a weight, like a book, on it in the middle the
>next time I want to make a platter; so that it doesn't want to warp
>upwards.
>
>Does anyone have any suggestions as to how to keep a platter, 10" X 17"
>from warping?
>
>Here is a link to the picture of the platter...you might be able to see a
>little bit from the picture how it has pulled up in the middle....
>
>http://pg.photos.yahoo.com/ph/tamaron2@sbcglobal.net/detail?.dir=3123&.dnm=fdad.jpg&.src=ph
>
>Thanks so much for your help,
>
>Tamara Petty
>Northern California
>
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>
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>
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>melpots@pclink.com.
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Annette Frank on thu 27 oct 05
Tamara, - I learned this trick at a workshop and it works fine for me.
Cut a foam form to fit the flat part of your platter and dry it upside down.
Annette
>
>
Tamara Petty on thu 27 oct 05
Hi Everyone!
Been learning so much from reading the mail that goes to the list! :-D
I'm a sculptor and not a potter (would love to learn the art of pottery too :-) ) but I recently helped a friend to make a fish platter. We rolled it out with a rolling pin - don't have a slab roller. :-( And it looked great at the beginning but now after a few days of drying the center area has risen quite a bit. The perimeter of the platter is flat on the table but the center area is bowed up.
We used a wire to release the clay from the table after rolling it out and shaping it and then put it on a paper bag so that it could shrink without cracking. We put a piece of plastic over it to help it slowly dry. I was wondering if I should put a weight, like a book, on it in the middle the next time I want to make a platter; so that it doesn't want to warp upwards.
Does anyone have any suggestions as to how to keep a platter, 10" X 17" from warping?
Here is a link to the picture of the platter...you might be able to see a little bit from the picture how it has pulled up in the middle....
http://pg.photos.yahoo.com/ph/tamaron2@sbcglobal.net/detail?.dir=3123&.dnm=fdad.jpg&.src=ph
Thanks so much for your help,
Tamara Petty
Northern California
JOYCE LEE on fri 28 oct 05
Tamara..... Dannon mentioned placing your platter on a piece of
drywall with another piece of top of it to retard the drying process and
help the platter dry more evenly. She also mentioned waxing the
rim for the same purpose. =20
When Dannon taught me these procedures several years ago, she also
added that the dry wall holding the platter would benefit from being
turned over from time to time during the drying process.. very =
carefully.
This is the procedure I follow. In addition, I make sure that the =
platter
spends less time with rim up since it's the bottom warpage which is our
concern. (Dannon Taught me that, too.)
Since I live in the desert where the problem is always complicated by
rapid drying, the platter's depth exposes the sides
of the top&bottom drywalled piece allowing air to get in, dry air.
I drape plastic over the whole thing to alleviate that exposure.
It sounds more time-consuming than it is and is well worth the effort.
I've made lots of platters and seldom have a warped one since using
this method.
Joyce
In the Mojave where it's dark and damp at 6 a.m. telling me that I'll
need to call the furnace guy to come check out mine..... seems like
a very short time since we did this last year....... it's absolutely
true about Time Flying as we age .. always heard it; thought I
understood it; thought I'd experienced it. Wrong! Nothing like now...
this decade is just as demanding as the others, but with the=20
disadvantage of time rushing on..............=20
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