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off the hump s-cracks

updated wed 17 oct 07

 

Eric Suchman on wed 10 oct 07


Check the archives...... Jonathon Kaplan's solution sounds the most
plausible and helpful.
Eric in Oceanside.


On Oct 10, 2007, at 3:30 PM, catherine seidenberg wrote:

> Anyone have fabulous expert tricks for preventing s-cracks on
> really thin wares thrown off-the-hump? I have pretty good luck with
> stoneware, but am about to embark on a batch of small porcelain
> sake/espresso cups.
>
>
> Catherine Seidenberg
>
>> Date: Wed, 10 Oct 2007 12:48:40 -0700
>> From: pjlewing@COMCAST.NET
>> Subject: Re: china paints
>> To: CLAYART@LSV.CERAMICS.ORG
>>
>> On Oct 9, 2007, at 3:56 PM, Russel Fouts wrote:
>>
>>>> There is such a thing as matte china paints, but they don't come
>> in the incredible range of colors that regular china paints do. <<
>>
>> Paul, I thought that china paints took on the texture of the surface
>> they were painted on. So, if you painted them on a matt glaze, they
>> would be matt. Or did I misunderstand something.
>>
>> Not exactly. Regular china paints do have some sheen to them, so
>> even on an unglazed surface, there will be some shine. They will be
>> shinier on a glossy surface and more matt on a matt surface, but they
>> don't completely take on the surface they're on. And they matt ones
>> are really matt no matter what you put them on.
>> Paul Lewing
>> www.paullewingtile.com
>>
>> _____________________________________________________________________
>> _________
>> Clayart members may send postings to: clayart@lsv.ceramics.org
>>
>> You may look at the archives for the list, post messages, or
>> change your
>> subscription settings here: http://www.acers.org/cic/clayart/
>>
>> Moderator of the list is Mel Jacobson who may be reached at
>> melpots2@visi.com
>
> _________________________________________________________________
> Climb to the top of the charts! Play Star Shuffle: the word
> scramble challenge with star power.
> http://club.live.com/star_shuffle.aspx?
> icid=starshuffle_wlmailtextlink_oct
> ______________________________________________________________________
> ________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, or change
> your
> subscription settings here: http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com

catherine seidenberg on wed 10 oct 07


Anyone have fabulous expert tricks for preventing s-cracks on really thin w=
ares thrown off-the-hump? I have pretty good luck with stoneware, but am ab=
out to embark on a batch of small porcelain sake/espresso cups.

=
Catherine Seidenberg

> Date: Wed, 10 Oct 2007 12:48:40 -0700
> From: pjlewing@COMCAST.NET
> Subject: Re: china paints
> To: CLAYART@LSV.CERAMICS.ORG
>=20
> On Oct 9, 2007, at 3:56 PM, Russel Fouts wrote:
>=20
> >> There is such a thing as matte china paints, but they don't come
> in the incredible range of colors that regular china paints do. <<
>=20
> Paul, I thought that china paints took on the texture of the surface
> they were painted on. So, if you painted them on a matt glaze, they
> would be matt. Or did I misunderstand something.
>=20
> Not exactly. Regular china paints do have some sheen to them, so
> even on an unglazed surface, there will be some shine. They will be
> shinier on a glossy surface and more matt on a matt surface, but they
> don't completely take on the surface they're on. And they matt ones
> are really matt no matter what you put them on.
> Paul Lewing
> www.paullewingtile.com
>=20
> _________________________________________________________________________=
_____
> Clayart members may send postings to: clayart@lsv.ceramics.org
>=20
> You may look at the archives for the list, post messages, or change your
> subscription settings here: http://www.acers.org/cic/clayart/
>=20
> Moderator of the list is Mel Jacobson who may be reached at melpots2@visi=
.com

_________________________________________________________________
Climb to the top of the charts!=A0 Play Star Shuffle:=A0 the word scramble =
challenge with star power.
http://club.live.com/star_shuffle.aspx?icid=3Dstarshuffle_wlmailtextlink_oc=
t=

Sabri Justin Douglas Ben-Achour on wed 10 oct 07


there are, in my experience, three keys to preventing S cracks both off the=
hump and off the bat:

1. compressing the bottom back and forth at length, in the same motions tha=
t would make spirals in the bottom of your cup (you don't have to make spir=
als, you can do it smoothly, just trying to describe the motion). (this co=
mpacts the clay, aligns the particles in a way that minimizes shrinking str=
esses, etc)

2. making sure that, whatever the thickness or thinness of your walls, the =
bottom is trimmed to that same thickness. any imbalance in the thickness/t=
hinness of the walls and the bottom will invite stresses as they dry at dif=
ferent rates, that will manifest themselves as S cracks at any time from bo=
ne dry to cone 10.=20

3. don't let slip sit in the bottom of any pot, during throwing if you can =
help it, but definitely once you are done. any moisture that sits in the b=
ottom of the pot while it is drying will dramatically increase the likeliho=
od of S cracks

Sabri
www.thesabritree.com

> Date: Wed, 10 Oct 2007 22:30:32 +0000
> From: catherineps@HOTMAIL.COM
> Subject: Re: off the hump s-cracks
> To: CLAYART@LSV.CERAMICS.ORG
>=20
> Anyone have fabulous expert tricks for preventing s-cracks on really thin=
wares thrown off-the-hump? I have pretty good luck with stoneware, but am =
about to embark on a batch of small porcelain sake/espresso cups.
>=20
> =
Catherine Seidenberg
>=20
> > Date: Wed, 10 Oct 2007 12:48:40 -0700
> > From: pjlewing@COMCAST.NET
> > Subject: Re: china paints
> > To: CLAYART@LSV.CERAMICS.ORG
> >=20
> > On Oct 9, 2007, at 3:56 PM, Russel Fouts wrote:
> >=20
> > >> There is such a thing as matte china paints, but they don't come
> > in the incredible range of colors that regular china paints do. <<
> >=20
> > Paul, I thought that china paints took on the texture of the surface
> > they were painted on. So, if you painted them on a matt glaze, they
> > would be matt. Or did I misunderstand something.
> >=20
> > Not exactly. Regular china paints do have some sheen to them, so
> > even on an unglazed surface, there will be some shine. They will be
> > shinier on a glossy surface and more matt on a matt surface, but they
> > don't completely take on the surface they're on. And they matt ones
> > are really matt no matter what you put them on.
> > Paul Lewing
> > www.paullewingtile.com
> >=20
> > _______________________________________________________________________=
_______
> > Clayart members may send postings to: clayart@lsv.ceramics.org
> >=20
> > You may look at the archives for the list, post messages, or change you=
r
> > subscription settings here: http://www.acers.org/cic/clayart/
> >=20
> > Moderator of the list is Mel Jacobson who may be reached at melpots2@vi=
si.com
>=20
> _________________________________________________________________
> Climb to the top of the charts! Play Star Shuffle: the word scramble ch=
allenge with star power.
> http://club.live.com/star_shuffle.aspx?icid=3Dstarshuffle_wlmailtextlink_=
oct
> _________________________________________________________________________=
_____
> Clayart members may send postings to: clayart@lsv.ceramics.org
>=20
> You may look at the archives for the list, post messages, or change your
> subscription settings here: http://www.acers.org/cic/clayart/
>=20
> Moderator of the list is Mel Jacobson who may be reached at melpots2@visi=
.com

_________________________________________________________________
Climb to the top of the charts!=A0 Play Star Shuffle:=A0 the word scramble =
challenge with star power.
http://club.live.com/star_shuffle.aspx?icid=3Dstarshuffle_wlmailtextlink_oc=
t=

Maggie Jones on wed 10 oct 07


also...pressure from the outside , at the base squeezing in, esp for hump
pieces.
Maggie

On Wed, 10 Oct 2007 23:41:59 +0000 Sabri Justin Douglas Ben-Achour
writes:
> there are, in my experience, three keys to preventing S cracks both
> off the hump and off the bat:
>
> 1. compressing the bottom back and forth at length, in the same
> motions that would make spirals in the bottom of your cup (you don't
> have to make spirals, you can do it smoothly, just trying to
> describe the motion). (this compacts the clay, aligns the particles
> in a way that minimizes shrinking stresses, etc)
>
> 2. making sure that, whatever the thickness or thinness of your
> walls, the bottom is trimmed to that same thickness. any imbalance
> in the thickness/thinness of the walls and the bottom will invite
> stresses as they dry at different rates, that will manifest
> themselves as S cracks at any time from bone dry to cone 10.
>
> 3. don't let slip sit in the bottom of any pot, during throwing if
> you can help it, but definitely once you are done. any moisture
> that sits in the bottom of the pot while it is drying will
> dramatically increase the likelihood of S cracks
>
> Sabri
> www.thesabritree.com
>
> > Date: Wed, 10 Oct 2007 22:30:32 +0000
> > From: catherineps@HOTMAIL.COM
> > Subject: Re: off the hump s-cracks
> > To: CLAYART@LSV.CERAMICS.ORG
> >
> > Anyone have fabulous expert tricks for preventing s-cracks on
> really thin wares thrown off-the-hump? I have pretty good luck with
> stoneware, but am about to embark on a batch of small porcelain
> sake/espresso cups.
> >
> >
> Catherine Seidenberg
> >
> > > Date: Wed, 10 Oct 2007 12:48:40 -0700
> > > From: pjlewing@COMCAST.NET
> > > Subject: Re: china paints
> > > To: CLAYART@LSV.CERAMICS.ORG
> > >
> > > On Oct 9, 2007, at 3:56 PM, Russel Fouts wrote:
> > >
> > > >> There is such a thing as matte china paints, but they don't
> come
> > > in the incredible range of colors that regular china paints do.
> <<
> > >
> > > Paul, I thought that china paints took on the texture of the
> surface
> > > they were painted on. So, if you painted them on a matt glaze,
> they
> > > would be matt. Or did I misunderstand something.
> > >
> > > Not exactly. Regular china paints do have some sheen to them,
> so
> > > even on an unglazed surface, there will be some shine. They
> will be
> > > shinier on a glossy surface and more matt on a matt surface, but
> they
> > > don't completely take on the surface they're on. And they matt
> ones
> > > are really matt no matter what you put them on.
> > > Paul Lewing
> > > www.paullewingtile.com
> > >
> > >
>
_________________________________________________________________________
_____
> > > Clayart members may send postings to:
> clayart@lsv.ceramics.org
> > >
> > > You may look at the archives for the list, post messages, or
> change your
> > > subscription settings here: http://www.acers.org/cic/clayart/
> > >
> > > Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
> >
> > _________________________________________________________________
> > Climb to the top of the charts! Play Star Shuffle: the word
> scramble challenge with star power.
> >
>
http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_oc
t
> >
>
_________________________________________________________________________
_____
> > Clayart members may send postings to: clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list, post messages, or
> change your
> > subscription settings here: http://www.acers.org/cic/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
>
> _________________________________________________________________
> Climb to the top of the charts! Play Star Shuffle: the word
> scramble challenge with star power.
>
http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_oc
t
>
_________________________________________________________________________
_____
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, or change
> your
> subscription settings here: http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots2@visi.com
>
>

John Kudlacek on tue 16 oct 07


Eric et.al,
I found generally that I virtually eliminated s-cracks in my standard
throwing by putting the wedged clay on the wheel "cross-wise" to the
wedging spiral as opposed to orienting it concentrically with the wheel.
You might give it a try for your "hump" throwing.
John Kudlacek

Eric Suchman on tue 16 oct 07


That's what I've deduced and plan to do. Thanks immensely,
Eric

Donna Kat on tue 16 oct 07


On Tue, 16 Oct 2007 15:52:00 -0500, John Kudlacek wrote:

>Eric et.al,
> I found generally that I virtually eliminated s-cracks in my standard
>throwing by putting the wedged clay on the wheel "cross-wise" to the
>wedging spiral as opposed to orienting it concentrically with the wheel.
>You might give it a try for your "hump" throwing.
> John Kudlacek
>

My 2 cents.

Since threads don't stick together on the list I haven't a clue if this
has already been stated so my apologies if I'm repeating. If you take
your wood trimming tool (rounded end), and push in at the =91foot=92 as you
are opening the floor, this aids in compressing the clay. Then when the
pot is leather hard tap on the bottom to further compress it.

Donna