mel jacobson on fri 11 feb 11
fred, please be more specific.
what and where are the cracks.
???details.
from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
new book: http://www.21stcenturykilns.com
alternate: melpots7575@gmail.com
Fred Parker on sat 12 feb 11
The cracks happen somewhere between the two join points -- not the join
itself. As I write this I realize my question is fundamentally flawed.=3D2=
0=3D
Paper clay would generally be useful for correcting a join problem, which=
=3D
is
not my problem. After reading over the comments I received I believe the=
=3D
issue is my own failure to equalize moisture in the entire piece by wrapp=
=3D
ing
in plastic for a time. I haven't been doing that -- only covering with a=
=3D
couple of sheets of newspaper, which works well for non-handled pieces, b=
=3D
ut
not for something with significant moisture differences between component=
=3D
s.
Fred=3D20
On Fri, 11 Feb 2011 14:48:22 -0600, mel jacobson wrot=
=3D
e:
>fred, please be more specific.
>what and where are the cracks.
>???details.
>from: minnetonka, mn
>website: http://www.visi.com/~melpots/
> clayart link: http://www.visi.com/~melpots/clayart.html
>new book: http://www.21stcenturykilns.com
>alternate: melpots7575@gmail.com
Lee on sat 12 feb 11
Fred, you said the body was leather hard. That may be the problem.
You need the body and handle to be as close to the same level of
hardness as possible. I've taken to pulling handles before I throw
the pot, let them dry a little and then put them in plastic and then
throw the bodies.
Also, at any stage before they are glaze fired, you can use
a popcicle stick to "heal" the seam. You can do it at leather, green
and even bisque. In Japan, we used a small bamboo stick, but a
popcicle stick is perfect. We would always inspect green and bisqued
mugs and teapots for any hint of a small crack or seam.
On Sat, Feb 12, 2011 at 10:25 AM, Fred Parker wrote:
> The cracks happen somewhere between the two join points -- not the join
> itself. =3DA0As I write this I realize my question is fundamentally flawe=
d.
> Paper clay would generally be useful for correcting a join problem, which=
=3D
is
> not my problem. =3DA0After reading over the comments I received I believe=
t=3D
he
> issue is my own failure to equalize moisture in the entire piece by wrapp=
=3D
ing
> in plastic for a time. =3DA0I haven't been doing that -- only covering wi=
th=3D
a
> couple of sheets of newspaper, which works well for non-handled pieces, b=
=3D
ut
> not for something with significant moisture differences between component=
=3D
s.
>
> Fred
>
> On Fri, 11 Feb 2011 14:48:22 -0600, mel jacobson wrot=
=3D
e:
>
>>fred, please be more specific.
>>what and where are the cracks.
>>???details.
>>from: minnetonka, mn
>>website: http://www.visi.com/~melpots/
>> =3DA0clayart link: =3DA0http://www.visi.com/~melpots/clayart.html
>>new book: http://www.21stcenturykilns.com
>>alternate: melpots7575@gmail.com
>
--=3D20
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Elizabeth Willoughby on sat 12 feb 11
Fred, before you attach the handle compress the clay by pushing the
ends of the handle towards the center. I believe the handles are
shrinking more than the mug, creating tension in the middle of the
handle.
Liz willoughby, sitting in the Toronto
airport waiting for the "call". We are off to New Mexico!
On Saturday, February 12, 2011, Fred Parker wrote:
> The cracks happen somewhere between the two join points -- not the join
> itself. =3DA0As I write this I realize my question is fundamentally flawe=
d.
> Paper clay would generally be useful for correcting a join problem, which=
=3D
is
> not my problem. =3DA0After reading over the comments I received I believe=
t=3D
he
> issue is my own failure to equalize moisture in the entire piece by wrapp=
=3D
ing
> in plastic for a time. =3DA0I haven't been doing that -- only covering wi=
th=3D
a
> couple of sheets of newspaper, which works well for non-handled pieces, b=
=3D
ut
> not for something with significant moisture differences between component=
=3D
s.
>
> Fred
>
> On Fri, 11 Feb 2011 14:48:22 -0600, mel jacobson wrot=
=3D
e:
>
>>fred, please be more specific.
>>what and where are the cracks.
>>???details.
>>from: minnetonka, mn
>>website: http://www.visi.com/~melpots/
>> =3DA0clayart link: =3DA0http://www.visi.com/~melpots/clayart.html
>>new book: http://www.21stcenturykilns.com
>>alternate: melpots7575@gmail.com
>
--=3D20
Liz Willoughby
Brighton/Grafton,
Ontario, Canada
Eric Hansen on sat 12 feb 11
i don't know how well they work, but Mick Casson's handles look really
strong visually
- h a n s e n -
http://www.google.com/images?client=3D3Dsafari&rls=3D3Den&q=3D3DMick+Casson=
&oe=3D3D=3D
UTF-8&um=3D3D1&ie=3D3DUTF-8&source=3D3Duniv&ei=3D3DjNdWTZvIIYKglAeP9d2eBw&s=
a=3D3DX&oi=3D
=3D3Dimage_result_group&ct=3D3Dtitle&resnum=3D3D3&ved=3D3D0CC4QsAQwAg
On Sat, Feb 12, 2011 at 1:41 PM, Elizabeth Willoughby
wrote:
> Fred, before you attach the handle compress the clay by pushing the
> ends of the handle towards the center. I believe the handles are
> shrinking more than the mug, creating tension in the middle of the
> handle.
> Liz willoughby, sitting in the Toronto
> airport waiting for the "call". =3DA0We are off to New Mexico!
>
> On Saturday, February 12, 2011, Fred Parker wrote:
>> The cracks happen somewhere between the two join points -- not the join
>> itself. =3DA0As I write this I realize my question is fundamentally flaw=
ed=3D
.
>> Paper clay would generally be useful for correcting a join problem, whic=
=3D
h is
>> not my problem. =3DA0After reading over the comments I received I believ=
e =3D
the
>> issue is my own failure to equalize moisture in the entire piece by wrap=
=3D
ping
>> in plastic for a time. =3DA0I haven't been doing that -- only covering w=
it=3D
h a
>> couple of sheets of newspaper, which works well for non-handled pieces, =
=3D
but
>> not for something with significant moisture differences between componen=
=3D
ts.
>>
>> Fred
>>
>> On Fri, 11 Feb 2011 14:48:22 -0600, mel jacobson wro=
=3D
te:
>>
>>>fred, please be more specific.
>>>what and where are the cracks.
>>>???details.
>>>from: minnetonka, mn
>>>website: http://www.visi.com/~melpots/
>>> =3DA0clayart link: =3DA0http://www.visi.com/~melpots/clayart.html
>>>new book: http://www.21stcenturykilns.com
>>>alternate: melpots7575@gmail.com
>>
>
> --
> Liz Willoughby
> Brighton/Grafton,
> Ontario, Canada
>
--=3D20
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
WJ Seidl on sun 13 feb 11
Fred and all:
That might be the case where the clay is unfired.
And, as you note, is an easily correctable issue with moisture equalization=
.
However, I've also noted that some handles will also crack (not on
joins, but somewhere in the middle)
when different types of clay are used for body vs. handle.
The joins hold (even without Mel and Nil's fingers), but the handle is
literally "pulled apart" by the shrinkage factor of the body of the mug.
This can happen during firing, during cool down, or even some time
afterward.
One of my favorite mugs is from porcelain; a tall, thin-walled, lithe
little thing with the most incredibly formed, but extremely thin handle,
made by a (then) student of Baltimore Clay Works. I got the mug from
BCW during the NCECA in that city...(anyone remember the hotel being
awash in red boa feathers? )
As soon as I got it home, I poured a cup of coffee (cold), added milk,
and went to lift the mug to my lips.
All I heard was "tick" and the handle cracked in two. Stress crack.
Joined at both ends, cracked across the middle.
Super glue to the rescue.
I don't use the mug often, afraid it will happen again, but it is still
a joy to look at. It's just a visual delight for me....kind of like Logan.
At one of my earlier ceramics classes (back when the earth was still
being formed, maybe a year or two after) an instructor had the "bright
idea" to make raku clay, and make the same clay but without all of the
grog to be used "for handles". "Easier pulling" he claimed. Throwing
the body clay was like throwing concrete, sanded your fingertips right
off...but I digress.
Every mug thrown with that "handle" clay used for handles cracked in
exactly the same way...somewhere in the middle. The instructor shrugged
and put the blame on the students, claiming that "we must not have
listened to him". (And boy I was some pissed off about that, too! I
hope he roasts in well, never mind. He was not a good instructor.)
What's the point? Make sure not only that your glaze fits your clay,
but that your handle clay fits your body clay.
Equalize your moisture, as Fred has discovered.
Stick your fingers in it to make a good join like Mel and Nils.
For good measure, eat your vegetables, change your underwear, give the
dog a cookie, and call your mother...she worries.
Best,
Wayne Seidl
On 2/12/2011 11:25 AM, Fred Parker wrote:
> The cracks happen somewhere between the two join points -- not the join
> itself. As I write this I realize my question is fundamentally flawed.
> Paper clay would generally be useful for correcting a join problem, which=
is
> not my problem. After reading over the comments I received I believe the
> issue is my own failure to equalize moisture in the entire piece by wrapp=
ing
> in plastic for a time. I haven't been doing that -- only covering with a
> couple of sheets of newspaper, which works well for non-handled pieces, b=
ut
> not for something with significant moisture differences between component=
s.
>
> Fred
>
>
Lee on sun 13 feb 11
On Sun, Feb 13, 2011 at 4:07 AM, WJ Seidl wrote:
> Fred and all:
> That might be the case where the clay is unfired.
> And, as you note, is an easily correctable issue with moisture equalizati=
=3D
on.
> However, I've also noted that some handles will also crack (not on
> joins, but somewhere in the middle)
This also happens when there is too much difference in moisture
between the body and the handle. Handles dry faster than bodies.
One way to help, given that you try to have the clays of the same
moisture in the beginning, is to cover them and let them dry slowly.
Make many. After 5,000 or so, the problems are less frequent.
Here are some I made and my teacher decorated. I was happy he chose
to put them in the first show at the contemporary gallery that was
created in Yanagi's house when it was rennovated:
http://mingeisota.blogspot.com/2011/01/joki.html
--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/
=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
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