Francis Rider on mon 4 feb 08
I need help with techniques in porcelain ! I have been working in
stoneware for the last 14 years and feel like I have a pretty good handle
on most techniques so I thought I would spend some time throwing and hand
building with porcelain. Well as many of you know it is a different beast.
I like to throw and alter larger forms, pitchers, footed vessels and I am
having a hell of a time with pieces cracking, handles peeling, small
cracks around foot attachments. I have tried attachments at soft leather
hard, medium leather hard, stiff leather hard, I dry very slowly but I
also live in a very dry climate. Sometimes everything looks great after
two weeks of slow drying and I pull the bag and the next morning I will
have cracks. I have tried about a dozen different porcelain bodies and I
am still loosing a bit of product. Throwing porcelain has made me better
on the wheel but I'm strugeling overall with this medium. Any
recomendations for books or techniques, workshops, would be greatley
appreciated.
Thanks
Francis Rider
vpitelka on tue 5 feb 08
Francis Rider wrote:
"I need help with techniques in porcelain ! I have been working in
stoneware for the last 14 years and feel like I have a pretty good handle
on most techniques so I thought I would spend some time throwing and hand
building with porcelain. Well as many of you know it is a different beast.
I like to throw and alter larger forms, pitchers, footed vessels and I am
having a hell of a time with pieces cracking, handles peeling, small
cracks around foot attachments. I have tried attachments at soft leather
hard, medium leather hard, stiff leather hard, I dry very slowly but I
also live in a very dry climate. Sometimes everything looks great after
two weeks of slow drying and I pull the bag and the next morning I will
have cracks. I have tried about a dozen different porcelain bodies and I
am still loosing a bit of product. Throwing porcelain has made me better
on the wheel but I'm strugeling overall with this medium. Any
recomendations for books or techniques, workshops, would be greatley
appreciated."
Francis -
I am curious as to why you made the move to porcelain, rather than to a
porcelaineous stoneware. The latter is far more forgiving. Remember, so
much of what we look for in clay performance comes from distribution of
particle sizes, both plastics and non-plastics. Traditional porcelain
bodies have a narrow range of particle sizes, and the particles are coarse
as clay particles go, especially if the body uses primary (residual)
kaolins. With larger particle, there are a lot of voids left even after
drying shrinkage takes place. Larger particles and lots of voids means a
lot less contact points between particles, which means very low dry/bisque
strength, and thus a greater inclination to crack at that point. It also
means high firing shrinkage as the glassy phase fills the spaces between the
refractory particles.
If you veer away from purely traditional porcelains, and don't care about
the purest whites, you will have a much easier time. You can greatly
broaden the particle distribution by using a combination of primary and
secondary kaolins plus ball clay, a little stoneware clay, and some Veegum-T
or Macaloid. Hard-core traditional porcelains generally contain 50% clay
and 50% non-plastics, but that makes for a clay body that is pretty weak at
the dry/bisque stage. You need supplemental flint and feldspar to get a
dense vitreous porcelain body, but not 50% of the body.
With a broad distribution of particle sizes you get -
Good plasticity and adhesion due to the small particles.
Good number of water layers for plasticity and lubrication, but not too many
water layers and few voids, due to the nestling of particles of many sizes -
thus lower drying shrinkage AND firing shrinkage.
Good working structure due to friction caused by the many contact points
between particles due to the nestling of particles of many sizes.
Good dry/bisque strength due to many contact points.
Aside from what they do for glassy phase and vitrification, adding
non-plastics in limited quantities improves working structure, decreases
drying shrinkage, and opens up the body to aid drying, but non-plastics
don't attract a water layer and thus decrease plasticity and adhesion. We
think of ground feldspar or silica as being a powder, but remember that most
ground glaze materials are between 200 and 300 mesh, which makes them huge
boulders in comparison to a clay platelet. Clay platelets average less than
two microns in size, which comes out to about two trillion platelets in a
cubic inch of clay. So it is easy to see the effect of non-plastics. We
need them, but for maximum plasticity you don't want to use any more than
necessary.
There are disadvantages to claybodies that have an average particle size too
small (poor working structure, high drying shrinkage, resulting cracking,
warping), and claybodies that have an average particle size too large (low
plasticity and adhesion, poor working structure, poor dry/bisque strength,
high firing shrinkage). A claybody with broad distribution of particle
sizes has all the advantages and none of the disadvantages.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
Rider,Francis - Art Studio Technician on wed 6 feb 08
Ivor
I do as I have learned over the years to score and slip but more recently I=
have been using Lana Wilson's magic water with no clay slip. Old habits di=
e hard and I have tried different techniques but I will definitely try your=
s, thanks to you and many others the information on clayart is incredible.=
I have only been serious about clay for the past 14 years wich I know is n=
othing compared to many of the master potters on this website. I have been =
an artrist for the good majority of my life, 25 years as a chef, 20 years a=
s a ice sculptor,15 years of metal ,wood, recycled and anything that came =
cheep so i do appreciate all the feedback that I can get. I have been bitte=
n by the clay bug and cant pull myself away I feel as if this is my second =
chance at life.
Sincerely
Francis Rider
________________________________________
From: Clayart [CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and Olive Lewis =
[iandol@WESTNET.COM.AU]
Sent: Tuesday, February 05, 2008 9:57 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Porcelain Blues (A Whole New BEAST)
Dear Francis Rider,
Perhaps if you were to give a description of the method you use to adhere o=
ne part to another you might get directions to cure this vexing problem.
My recommendation for what it is worth is not to score the clay. Leave both=
joining surfaces smooth. Then use thickened deflocculated clay body as the=
adhesive.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
___________________________________________________________________________=
___
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers=
.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.c=
om
Rider,Francis - Art Studio Technician on wed 6 feb 08
Thanks Vince
I think the porcelain gig for me was more about the challenge than anything=
else. I like to push myself so I don't settle into too much of a comfort z=
one. I felt if I could handle porcelain I could handle anything thrown at m=
e (no pun intended). That was a great explanation of the material, thank yo=
u for your time. So many things to learn in so little time.
Thanks Again
Francis Rider
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of vpitelka
Sent: Tuesday, February 05, 2008 4:55 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Porcelain Blues (A Whole New BEAST)
Francis Rider wrote:
"I need help with techniques in porcelain ! I have been working in
stoneware for the last 14 years and feel like I have a pretty good handle
on most techniques so I thought I would spend some time throwing and hand
building with porcelain. Well as many of you know it is a different beast.
I like to throw and alter larger forms, pitchers, footed vessels and I am
having a hell of a time with pieces cracking, handles peeling, small
cracks around foot attachments. I have tried attachments at soft leather
hard, medium leather hard, stiff leather hard, I dry very slowly but I
also live in a very dry climate. Sometimes everything looks great after
two weeks of slow drying and I pull the bag and the next morning I will
have cracks. I have tried about a dozen different porcelain bodies and I
am still loosing a bit of product. Throwing porcelain has made me better
on the wheel but I'm strugeling overall with this medium. Any
recomendations for books or techniques, workshops, would be greatley
appreciated."
Francis -
I am curious as to why you made the move to porcelain, rather than to a
porcelaineous stoneware. The latter is far more forgiving. Remember, so
much of what we look for in clay performance comes from distribution of
particle sizes, both plastics and non-plastics. Traditional porcelain
bodies have a narrow range of particle sizes, and the particles are coarse
as clay particles go, especially if the body uses primary (residual)
kaolins. With larger particle, there are a lot of voids left even after
drying shrinkage takes place. Larger particles and lots of voids means a
lot less contact points between particles, which means very low dry/bisque
strength, and thus a greater inclination to crack at that point. It also
means high firing shrinkage as the glassy phase fills the spaces between th=
e
refractory particles.
If you veer away from purely traditional porcelains, and don't care about
the purest whites, you will have a much easier time. You can greatly
broaden the particle distribution by using a combination of primary and
secondary kaolins plus ball clay, a little stoneware clay, and some Veegum-=
T
or Macaloid. Hard-core traditional porcelains generally contain 50% clay
and 50% non-plastics, but that makes for a clay body that is pretty weak at
the dry/bisque stage. You need supplemental flint and feldspar to get a
dense vitreous porcelain body, but not 50% of the body.
With a broad distribution of particle sizes you get -
Good plasticity and adhesion due to the small particles.
Good number of water layers for plasticity and lubrication, but not too man=
y
water layers and few voids, due to the nestling of particles of many sizes =
-
thus lower drying shrinkage AND firing shrinkage.
Good working structure due to friction caused by the many contact points
between particles due to the nestling of particles of many sizes.
Good dry/bisque strength due to many contact points.
Aside from what they do for glassy phase and vitrification, adding
non-plastics in limited quantities improves working structure, decreases
drying shrinkage, and opens up the body to aid drying, but non-plastics
don't attract a water layer and thus decrease plasticity and adhesion. We
think of ground feldspar or silica as being a powder, but remember that mos=
t
ground glaze materials are between 200 and 300 mesh, which makes them huge
boulders in comparison to a clay platelet. Clay platelets average less tha=
n
two microns in size, which comes out to about two trillion platelets in a
cubic inch of clay. So it is easy to see the effect of non-plastics. We
need them, but for maximum plasticity you don't want to use any more than
necessary.
There are disadvantages to claybodies that have an average particle size to=
o
small (poor working structure, high drying shrinkage, resulting cracking,
warping), and claybodies that have an average particle size too large (low
plasticity and adhesion, poor working structure, poor dry/bisque strength,
high firing shrinkage). A claybody with broad distribution of particle
sizes has all the advantages and none of the disadvantages.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
___________________________________________________________________________=
___
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers=
.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.c=
om
Ivor and Olive Lewis on wed 6 feb 08
Dear Francis Rider,
Perhaps if you were to give a description of the method you use to =
adhere one part to another you might get directions to cure this vexing =
problem.
My recommendation for what it is worth is not to score the clay. Leave =
both joining surfaces smooth. Then use thickened deflocculated clay body =
as the adhesive.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
vpitelka on wed 6 feb 08
Francis -
For twenty years I have constantly been working on becoming a better
teacher. That sounds like some kind of martyrdom, and I don't mean it as
that. It is out of the passion for teaching that I am always striving to
learn more, so that I can explain it to my students more clearly and get
them to understand the core of the process. I finally feel like I can
explain the behavior of clays and claybodies very clearly, and the proof is
in the fact that my students are always referring to particle size
distribution and flocculants and primary and secondary clays etc. It is
gratifying to have them take this stuff so seriously. So, inevitably, I do
the same thing on Clayart. And it means a lot when I get a note like yours.
- Vince
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Rider,Francis -
Art Studio Technician
Sent: Wednesday, February 06, 2008 4:09 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Porcelain Blues (A Whole New BEAST)
Thanks Vince
I think the porcelain gig for me was more about the challenge than anything
else. I like to push myself so I don't settle into too much of a comfort
zone. I felt if I could handle porcelain I could handle anything thrown at
me (no pun intended). That was a great explanation of the material, thank
you for your time. So many things to learn in so little time.
Thanks Again
Francis Rider
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of vpitelka
Sent: Tuesday, February 05, 2008 4:55 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Porcelain Blues (A Whole New BEAST)
Francis Rider wrote:
"I need help with techniques in porcelain ! I have been working in
stoneware for the last 14 years and feel like I have a pretty good handle
on most techniques so I thought I would spend some time throwing and hand
building with porcelain. Well as many of you know it is a different beast.
I like to throw and alter larger forms, pitchers, footed vessels and I am
having a hell of a time with pieces cracking, handles peeling, small
cracks around foot attachments. I have tried attachments at soft leather
hard, medium leather hard, stiff leather hard, I dry very slowly but I
also live in a very dry climate. Sometimes everything looks great after
two weeks of slow drying and I pull the bag and the next morning I will
have cracks. I have tried about a dozen different porcelain bodies and I
am still loosing a bit of product. Throwing porcelain has made me better
on the wheel but I'm strugeling overall with this medium. Any
recomendations for books or techniques, workshops, would be greatley
appreciated."
Francis -
I am curious as to why you made the move to porcelain, rather than to a
porcelaineous stoneware. The latter is far more forgiving. Remember, so
much of what we look for in clay performance comes from distribution of
particle sizes, both plastics and non-plastics. Traditional porcelain
bodies have a narrow range of particle sizes, and the particles are coarse
as clay particles go, especially if the body uses primary (residual)
kaolins. With larger particle, there are a lot of voids left even after
drying shrinkage takes place. Larger particles and lots of voids means a
lot less contact points between particles, which means very low dry/bisque
strength, and thus a greater inclination to crack at that point. It also
means high firing shrinkage as the glassy phase fills the spaces between the
refractory particles.
If you veer away from purely traditional porcelains, and don't care about
the purest whites, you will have a much easier time. You can greatly
broaden the particle distribution by using a combination of primary and
secondary kaolins plus ball clay, a little stoneware clay, and some Veegum-T
or Macaloid. Hard-core traditional porcelains generally contain 50% clay
and 50% non-plastics, but that makes for a clay body that is pretty weak at
the dry/bisque stage. You need supplemental flint and feldspar to get a
dense vitreous porcelain body, but not 50% of the body.
With a broad distribution of particle sizes you get -
Good plasticity and adhesion due to the small particles.
Good number of water layers for plasticity and lubrication, but not too many
water layers and few voids, due to the nestling of particles of many sizes -
thus lower drying shrinkage AND firing shrinkage.
Good working structure due to friction caused by the many contact points
between particles due to the nestling of particles of many sizes.
Good dry/bisque strength due to many contact points.
Aside from what they do for glassy phase and vitrification, adding
non-plastics in limited quantities improves working structure, decreases
drying shrinkage, and opens up the body to aid drying, but non-plastics
don't attract a water layer and thus decrease plasticity and adhesion. We
think of ground feldspar or silica as being a powder, but remember that most
ground glaze materials are between 200 and 300 mesh, which makes them huge
boulders in comparison to a clay platelet. Clay platelets average less than
two microns in size, which comes out to about two trillion platelets in a
cubic inch of clay. So it is easy to see the effect of non-plastics. We
need them, but for maximum plasticity you don't want to use any more than
necessary.
There are disadvantages to claybodies that have an average particle size too
small (poor working structure, high drying shrinkage, resulting cracking,
warping), and claybodies that have an average particle size too large (low
plasticity and adhesion, poor working structure, poor dry/bisque strength,
high firing shrinkage). A claybody with broad distribution of particle
sizes has all the advantages and none of the disadvantages.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
____________________________________________________________________________
__
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
____________________________________________________________________________
__
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
Rider,Francis - Art Studio Technician on thu 7 feb 08
Thanks Bill
It is great to be a part of clayart and have so many people with so much kn=
owledge. There have been many different techniques passed along to me in th=
e past couple of days and I plan on trying each and everyone of them and fi=
nd what works for me. You guys are all great, I have had responses from all=
around the country and the world and value all of them. My belief is that =
there are many ways to achieve your goals and you must determine what works=
for you and the same goes for ceramics. I worked as a chef for the better =
part of my life and it is amazing how the two professions have so many thin=
gs in common, tools, trends, techniques,recipes,hard work and historical in=
fluences. I know the salary range is a bit off but to be happy in clay is w=
orth a million.
Thanks
Francis Rider
Lake Tahoe Ca.
________________________________________
From: Clayart [CLAYART@LSV.CERAMICS.ORG] On Behalf Of Bill Merrill [BILLM@P=
CADMIN.CTC.EDU]
Sent: Thursday, February 07, 2008 10:41 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Porcelain Blues (A Whole New BEAST)
Francis,
Using vinegar and mashing it up with some of your clay body works for
putting on handles on stoneware pot, or merely brushing vinegar on the
pot where the handle goes will work well if after the vinegar you score
the clay. I pull handled from pots, with the pitcher in my left hand
and pulling the clay with my right hand. When trying to hand build a
large
Pot using strips of clay, I wouldn't use vinegar as the slip you put
between the strips don't shrink and even if you use a serrated rib to
smooth the ridge, the joint will show. Simply keep the top edge of the
strip soft enough to add and smooth out another layer. You can make the
strip/slab a little thicker on the end you are going to attach to the
lowest strip of clay. With the top piece being a little thicker you can
smooth over and paddle the strips together without a seam showing. The
seam will show after firing , even if you rib it out as the slip doesn't
shrink as much as your clay body.
I am not a porcelain potter. My son is and I see him just using water ,
smooth the water on both sides of the joint ansnd press them together
and also give the piece s a little twist back and forth, The smoot out
the joint. That works for him
Bill Merrill
billm@pcadmin.ctc.edu
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and
Olive Lewis
Sent: Tuesday, February 05, 2008 9:58 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Porcelain Blues (A Whole New BEAST)
Dear Francis Rider,
Perhaps if you were to give a description of the method you use to
adhere one part to another you might get directions to cure this vexing
problem.
My recommendation for what it is worth is not to score the clay. Leave
both joining surfaces smooth. Then use thickened deflocculated clay body
as the adhesive.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
________________________________________________________________________
______
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
___________________________________________________________________________=
___
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers=
.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.c=
om
Lee on thu 7 feb 08
Francis,
Maybe you could try a step program? Here in Japan, they use
something called "hanjiki", meaning half porcelain. It is half
porcelain and half light colored stoneware. And is much less
expensive.
You could try half & half and graduate to 2/3 to 1/3 and
3/4 to 1/4.
In my wood kiln I prefer the hanjiki, because it is
stronger and has some iron in it for the wood kiln.
--
Lee in Mashiko, Tochigi Japan
http://mashikopots.blogspot.com/
"Tea is nought but this: first you heat the water, then you make the
tea. Then you drink it properly. That is all you need to know."
--Sen No Rikyu
"Let the beauty we love be what we do." - Rumi
Rider,Francis - Art Studio Technician on thu 7 feb 08
Hi Lee
Thanks for the input, I will try that method and see how it goes. I guess I=
should have put in my post I have been working with Laguna B-Mix which is =
a white creamy stoneware clay body. At first I struggled with it also but I=
have been able to develop a much lighter touch. I am enjoying the challeng=
e of porcelain, just a little frustrated at losing a good bit of work to cr=
acking. I checked out your blog and your work has a very warm feel to it. I=
would like to hold one of your tea bowls I bet they feel great.
Thanks again
Francis Rider
Lake Tahoe Ca.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Lee
Sent: Thursday, February 07, 2008 1:54 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Porcelain Blues (A Whole New BEAST)
Francis,
Maybe you could try a step program? Here in Japan, they use
something called "hanjiki", meaning half porcelain. It is half
porcelain and half light colored stoneware. And is much less
expensive.
You could try half & half and graduate to 2/3 to 1/3 and
3/4 to 1/4.
In my wood kiln I prefer the hanjiki, because it is
stronger and has some iron in it for the wood kiln.
--
Lee in Mashiko, Tochigi Japan
http://mashikopots.blogspot.com/
"Tea is nought but this: first you heat the water, then you make the
tea. Then you drink it properly. That is all you need to know."
--Sen No Rikyu
"Let the beauty we love be what we do." - Rumi
___________________________________________________________________________=
___
Clayart members may send postings to: clayart@lsv.ceramics.org
You may look at the archives for the list, post messages, change your
subscription settings or unsubscribe/leave the list here: http://www.acers=
.org/cic/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.c=
om
David McBeth on thu 7 feb 08
I have not followed this discussion as closely as I should have so =
forgive irrelatvent comments here but... I have been throwing porcelain =
almost=20
exclusivley for the last 6 to 8 years. I was told in grad school - =
think twice about using porcelain, it is very hard to throw. I have =
come to=20
understand over the years that any "bad" throwing body is hard to throw. =
Having tried numerous commercial porcelains over the years I highly=20
recommend Standard Ceramics Grolleg Porcelain #257. It is a very white, =
translucent, plastic, forgiving clay body. I have routinely fired it to =
a=20
hot Cone 10 in heavy reduction, gas; and to Cone 12+ in Mel's gas kiln =
in Wisconsin, the woodkiln at the Appalachian Crafts Center, and to=20
Cone 13 (approx) in a wood kiln at Waubonnsee community College in =
Illinois. Very wide platters/bowls on narrow feet tend to warp some=20
at a hard cone 10, cups with a very thin underside slightly slump =
ocassionaly but those are throwing/trimming issues - not clay problems. =
The bottom line is understanding the material, respecting it and working =
with the clay according to what it can do. The broad, low bowls I make=20
with the #257 porcelain could never be thrown the same way with Lizella =
stoneware clay.
Dave
David McBeth
330 B Gooch Hall
Department of Visual and Theatre Arts
University of Tennessee at Martin
Martin, Tennessee 38238
731-881-7416
http://davidmcbeth.blogspot.com
Bill Merrill on thu 7 feb 08
Francis,
Using vinegar and mashing it up with some of your clay body works for
putting on handles on stoneware pot, or merely brushing vinegar on the
pot where the handle goes will work well if after the vinegar you score
the clay. I pull handled from pots, with the pitcher in my left hand
and pulling the clay with my right hand. When trying to hand build a
large=20
Pot using strips of clay, I wouldn't use vinegar as the slip you put
between the strips don't shrink and even if you use a serrated rib to
smooth the ridge, the joint will show. Simply keep the top edge of the
strip soft enough to add and smooth out another layer. You can make the
strip/slab a little thicker on the end you are going to attach to the
lowest strip of clay. With the top piece being a little thicker you can
smooth over and paddle the strips together without a seam showing. The
seam will show after firing , even if you rib it out as the slip doesn't
shrink as much as your clay body.
I am not a porcelain potter. My son is and I see him just using water ,
smooth the water on both sides of the joint ansnd press them together
and also give the piece s a little twist back and forth, The smoot out
the joint. That works for him
Bill Merrill
billm@pcadmin.ctc.edu
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and
Olive Lewis
Sent: Tuesday, February 05, 2008 9:58 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Porcelain Blues (A Whole New BEAST)
Dear Francis Rider,
Perhaps if you were to give a description of the method you use to
adhere one part to another you might get directions to cure this vexing
problem.
My recommendation for what it is worth is not to score the clay. Leave
both joining surfaces smooth. Then use thickened deflocculated clay body
as the adhesive.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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Lee on fri 8 feb 08
On Feb 8, 2008 2:02 AM, Rider,Francis - Art Studio Technician
wrote:
> Thanks for the input, I will try that method and see how it goes. I guess I should
> have put in my post I have been working with Laguna B-Mix which is a white creamy
> stoneware clay body. At first I struggled with it also but I have been able to develop
> a much lighter touch. I am enjoying the challenge of porcelain, just a little frustrated
> at losing a good bit of work to cracking. I checked out your blog and your work has
> a very warm feel to it. I would like to hold one of your tea bowls I bet they feel great.
Thanks for the kind words Francis,
Maybe David McB is on to something. The cracking
doesn't sound normal to me. Can you try some different porcelains?
I just thought of something else: Do you use much water?
Throwing with slip might help with the cracking.
I like to do porcelain from time to time. I like the
colors in wood fire and also a white background for certain glazes.
Keep at it!
--
Lee in Mashiko, Tochigi Japan
http://mashikopots.blogspot.com/
"Tea is nought but this: first you heat the water, then you make the
tea. Then you drink it properly. That is all you need to know."
--Sen No Rikyu
"Let the beauty we love be what we do." - Rumi
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