Brian Molanphy on tue 11 dec 01
snail wrote:
'Most china is
bisque-fired to its maturation temperature, then
low-fired for the glaze coat - sort of the opposite
of porcelain. '
industrial porcelain is fired this way, isn't it? first fired unglazed to
maturity, then glost-fired with glaze. the first firing is hotter than what
studio potters use, like ^15. now i can't resist opening this can of worms:
is the stuff that studio potters fire to ^10-12 real porcelain, or is it
very white, fine-grained stoneware? are some of the commercially-available
porcelains made for wheel-throwing really porcelain and some not?
brian
Antoinette Badenhorst on thu 15 oct 09
=3DC2=3DA0=3D20
The little that I know about BONE CHINA is that potters do not waste their =
=3D
time to try and throw it; they make it into a slip and slip cast. Dry stren=
=3D
gth is poor, so they often low bisque fire before finishing the surface and=
=3D
they use drills and other mechanical equipment to decorate their pieces ( =
=3D
mostly simple shapes, to prevent collapses) Plasticity is lesser than porce=
=3D
lain (calcinied cow bones are not plastic!) Often times the outside is left=
=3D
unglazed, but polished.=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Kenneth Clark describes it in his book The Potters Manual as:........ a bod=
=3D
y with poor mechanical strength that will "fuse into a tough glass-like sub=
=3D
stance and temperatures over 1240C/2260F....limited top firing range after =
=3D
which it quickly looses shape and collapses". He also states that only pott=
=3D
ers with considerable experience in ceramic will take it on.=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Answering Lou on=3DC2=3DA0a comment:=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Antionette,=3D20
=3DC2=3DA0=3D20
porcelain.......or maybe because the clay is so tedious to work with=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Tedious yes, but not really so difficult.=3D20
=3DC2=3DA0=3D20
Regards,=3D20
=3DC2=3DA0=3D20
Lou Turner,=3D20
=3DC2=3DA0=3D20
The Woodlands, TX=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Lou there is few people that can be successful with PORCELAIN from day one.=
=3D
it normally takes some experience. I taught pottery since 1985 and started=
=3D
working with (translucent) porcelain since 1995. To this day it takes me a=
=3D
few throws to get it right when I was off the wheel for some time and new =
=3D
shapes always needs to be planned and practiced. I consider myself to be an=
=3D
experienced and good thrower........=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Many experienced potters were challenged before in my studio when they trie=
=3D
d to throw porcelain. Many got humbled by porcelain clay. (.........as it h=
=3D
umbles me every day of my life!) If it does not get you during throwing, it=
=3D
might get you during trimming and if it does not get you there, it will su=
=3D
re get you in the glazing or firing.=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
That being said: I tested and reported about ^6 porcelain bodies from Lagun=
=3D
a and Standard Ceramic in Pottery Making Illustrated (April/May issue) earl=
=3D
ier this year. There are some of these porcelains that become easier to wor=
=3D
k with and will probably get easier to work with all the time. Of cause cal=
=3D
ling it "porcelain" also keeps the controversy going. More raw materials ge=
=3D
t discovered everyday........=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Hand building with porcelain clay is also more challenging. Some of the big=
=3D
gest challenges with any porcelain body are controlling the moist content i=
=3D
n the clay. Until you understand what you are dealing with (and even then..=
=3D
..) you will get cracks. Until your hands learned to handle porcelain clay =
=3D
gently but firmly, you will loose up to 50% of your work. Experienced potte=
=3D
rs still deal with cracks all the time. Ask someone like Curtis Benzle. We =
=3D
learn to live with cracks and use them to our benefit.=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
The last comment that I want to make about porcelain is that it is easIER t=
=3D
o keep porcelain clay thicker, but then there is the question of why using =
=3D
porcelain clay if a stoneware will give you just the same results? There ar=
=3D
e other considerations in using porcelain though: I have used it previously=
=3D
for its fineness, whiteness and smoothness, susceptibility to textures. It=
=3D
is generally more expensive than other white clay bodies and has its own g=
=3D
lazing challenges.=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
=3DC2=3DA0=3D20
Well....enough said. Let's explore more about BONE CHINA . There is very li=
=3D
ttle studio information available on this subject.=3D20
Antoinette Badenhorst=3D20
Lincolnshire, Illinoise=3D20
May Luk on fri 16 oct 09
Dinah;
Do you have the David Leach Porcelain recipe? It was in that Kenneth Clark
book, which I have borrowed from the library 7 years ago (and returned
without penalty). I remember there are only 4 materials: feldpar, china
clay, silica and ball clay. I made some paper porcelain from scratch for
raku and it was fun. Would like to try it again.
Thanks!
May
Brooklyn NY
On Fri, Oct 16, 2009 at 7:04 PM, Dinah Snipes Steveni <
jd.steveni@comcast.net> wrote:
> Hi Clayart
>
>
>
> We all push and pull from this strand of bone and porcelain. I think I
> walked away from it in the 80's. We all achieve amazing results from our
> testing and results. Or should do. If you don't test and are just lurking=
in
> Clayart to glean bits and pieces then you're a fool. This past year, for
> instance, I made several porcelain bodies from Dame Lucie Rie's recipes
> which I cross referenced and then researched in various publications I o=
wn.
> Not so sure I want to share these results with all and sundry; which open=
s a
> new thread" worked them in Soda Feldspar and Potash Feldspar in order to
> find more interesting color. More later if asked.
>
>
>
> Dinah
> http://www.dinahsnipessteveni.com
> http://www.dianthusceramics.blogspot.com
> http://www.skagitartiststogether.com
>
--
http://twitter.com/MayLuk
http://www.flickr.com/groups/handmade_mugs/
claybuds@ATT.NET on fri 16 oct 09
Antoinette,
Yes, I also struggle constantly=3DC2=3DA0from=3DC2=3DA0questioning=3DC2=3DA=
0by=3DC2=3DA0cus=3D
tomers to make a distinction between porcelain and "pottery." " What's the =
=3D
difference between porcelain and pottery?" Or, in the=3DC2=3DA0elegant=3DC2=
=3DA0and=3D
sophisticated parlance of an occasional customer, "I see you still makin =
=3D
them potteries!"
If my customers recognize what I do, it is in the context of bone china, fo=
=3D
r that is their only reference point. Therefore, it is expected to be=3DC2=
=3DA0=3D
extrememly LIGHT. I have tried a hundred times to explain that bone china i=
=3D
s made by an entirely different process, that my porcelain pottery is made=
=3D
by hand on the wheel, etc. I try to explain that maximum lightness often m=
=3D
eans that the first time the pot is banged around in the dishwasher or the =
=3D
dishwater, it will likely crack if it's extremely thin, that I go for a wei=
=3D
ght that will mean a durable pot for many years of use. No attempt at any e=
=3D
xplanation seems to matter.
I have often thought about the brevity and concise=3DC2=3DA0(Chinese,=3DC2=
=3DA0not=3D
=3DC2=3DA0Marco=3DC2=3DA0Polo) term tz'u, applied equally to stoneware and =
porcelai=3D
n, for any vitrified pot that rings when lightly struck.=3DC2=3DA0Marco=3DC=
2=3DA0Po=3D
lo=3DC2=3DA0coined=3DC2=3DA0the=3DC2=3DA0term=3DC2=3DA0porcelain,=3DC2=3DA0=
from=3DC2=3DA0porcelino,=3D
=3DC2=3DA0"little=3DC2=3DA0pig,"=3DC2=3DA0from=3DC2=3DA0a=3DC2=3DA0small co=
wrie=3DC2=3DA0shell=3DC2=3D
=3DA0that=3DC2=3DA0was=3DC2=3DA0equated=3DC2=3DA0
with=3DC2=3DA0the=3DC2=3DA0look=3DC2=3DA0of=3DC2=3DA0a=3DC2=3DA0pig. In so =
many ways, it seems =3D
to me that I am struggling to find out insights that were common knowledge=
=3D
=3DC2=3DA0among=3DC2=3DA0Chinese=3DC2=3DA0porcelain=3DC2=3DA0potters a thou=
sand years ago. =3D
The latest "discovery" is how beautifully certain glazes are enhanced by a =
=3D
dark stoneware body, and how others are appropriate only for porcelain. Thi=
=3D
s is the way in which I am discovering an overall feeling of softness or h=
=3D
ardness to the finished work. I completely agree with you. Bone china has a=
=3D
lways struck me as cold and harsh.
David
=3DC2=3DA0 -------------- Original message from clayart_friends10@comcast.=
net:=3D
--------------=3D20
p { margin: 0; }I am very familiar with your research work with porcelain, =
=3D
David. In fact you sent me a copy of the way you mix your clay some years b=
=3D
ack. I think you've done well and I do not misjudge your knowledge for one =
=3D
single day. I also have an appreciation for your passion.=3DC2=3DA0In the g=
ener=3D
al public mouth bone china is refered to as chinaware. I have a constant st=
=3D
ruggle to explain to people that my work is not china. =3DC2=3DA0There is a=
sto=3D
ry about a girl allowing a bird to fly away and when the bird came back, sh=
=3D
e knew it belonged to her. We need to be careful that we do not 'kill" our =
=3D
precious porcelain by over protecting it. I know it is hard, not to do that=
=3D
, particularly if one learned ( and continue learning) the hard way and con=
=3D
stantly have people making it off as " just another claybody"=3DC2=3DA0 If =
we w=3D
ant to go strictly by the history of porcelain to name it, the only true po=
=3D
rcelain is Tz=3DE2=3D80=3D99u=3DE2=3D80=3D99 as originallu named by Marco P=
olo, but we =3D
know that Botger "discovered" porcelain afterwards and since then many reci=
=3D
pes, some translucent at one firing and another translucent at another firi=
=3D
ng saw the light. Some were not at al translucent. One had this ring and an=
=3D
other a different ring. The more raw materials, the more diffrent porcelain=
=3D
s.To complicat things more: many other uses for porcelain=3DC2=3DA0develope=
d. F=3D
act is=3DC2=3DA0that=3DC2=3DA0porcelain,distincts itself naturally from oth=
er clayb=3D
odies and those with an eye for it recognize it right away. There is someth=
=3D
ing "soft"=3DC2=3DA0about porcelain. Bone china is beautiful, but=3DC2=3DA0=
harch. W=3D
hy do I say that........? I don't know, I just know..................=3D=
C2=3D
=3DA0Dear Antoinette,
=3DC2=3DA0After 30 years of throwing and=3DC2=3DA0making=3DC2=3DA0and testi=
ng every por=3D
celain body I could=3DC2=3DA0dream=3DC2=3DA0up=3DC2=3DA0or get my hands on,=
I feel like=3D
I'm beginning to get what it is, from the standpoint of the needs of a=3DC=
2=3D
=3DA0porcelain potter who uses a wheel. This experience=3DC2=3DA0naturally =
colors=3D
my own expectations and my viewpoint, but its=3DC2=3DA0also fun to play de=
vils=3D
advocate. As a result of my response to Mel's question, I have seven full =
=3D
pages of text to learn from, and some reading in Nigel Wood's Chinese Glaze=
=3D
s to do.I=3DC2=3DA0just want to know the truth, and I want to use the very =
best=3D
.
=3DC2=3DA0=3DC2=3DA0I grew up around set after complete set of bone china,=
=3DC2=3DA0hav=3D
ing=3DC2=3DA0been collected incessantly by my great aunts and passed down t=
he g=3D
enerations. I was just looking again this past weekend at aunt Daughty's se=
=3D
t of Limoges, bought as a wedding gift for her and her first husband in 190=
=3D
0. It most certainly LOOKS like porcelain, but for a body with 50% flux in =
=3D
it and an extremely short firing range, I'm not interested in pursuing it. =
=3D
The ware would fool anyone not familiar with the difference between porcela=
=3D
in and bone china.
=3DC2=3DA0=3DC2=3DA0I can never forget my roots as a stoneware potter, so m=
y goal h=3D
as been to create a clay body that is unmistakable as a porcelain body in i=
=3D
ts fired state, but that has=3DC2=3DA0most of the workability of stoneware.=
Aft=3D
er twenty years of searching and learning, I've done it,=3DC2=3DA0and as Ma=
tt K=3D
atz and Dave Finkelnburg know, the secret is not just the composition of th=
=3D
e body, its how the body is mixed. Bravo to Matt and Dave and Dr.Carty. Che=
=3D
ck out www.mattanddavesclays.com y'all, and have some fun!
David Beumee
Porcelain by David Beumee
806 East Baseline=3D20
Lafayette, CO =3DC2=3DA080026
www.davidbeumee.com
Antoinette Badenhorst
Lincolnshire, Illinoise
Dinah Snipes Steveni on fri 16 oct 09
Hi Clayart=3D20
We all push and pull from this strand of bone and porcelain. I think I walk=
=3D
ed away from it in the 80's. We all achieve amazing results from our testin=
=3D
g and results. Or should do. If you don't test and are just lurking=3DC2=3D=
A0in=3D
Clayart to glean bits and pieces then you're a fool. This past year, for i=
=3D
nstance, =3DC2=3DA0I made several porcelain bodies from Dame Lucie Rie's re=
cipe=3D
s which I cross referenced and then researched in various publications I=3D=
C2=3D
=3DA0 own. Not so sure I want to share these results with all and sundry; w=
hi=3D
ch=3DC2=3DA0opens a new thread" worked them in Soda Feldspar and Potash Fel=
dspa=3D
r in order to find more interesting color. More later if asked.=3D20
Dinah=3D20
http://www.dinahsnipessteveni.com=3D20
http://www.dianthusceramics.blogspot.com=3D20
http://www.skagitartiststogether.com=3D20
Lee Love on fri 16 oct 09
On Thu, Oct 15, 2009 at 5:49 PM, wrote:
> Dear Antoinette,
> =3DA0After 30 years of throwing and=3DA0making=3DA0and testing every porc=
elain =3D
body I could=3DA0dream=3DA0up=3DA0or get my hands on, I feel like I'm begin=
ning t=3D
o get what it is, from the standpoint of the needs of a=3DA0porcelain potte=
r =3D
who uses a wheel.
Continental's woodfire porcelain throws pretty good.
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Lee Love on sat 17 oct 09
On Fri, Oct 16, 2009 at 10:37 PM, May Luk wrote:
> Dinah;
> Do you have the David Leach Porcelain recipe?
From the archives, found on Google:
David Leach Porcelain Cone 10 reduction
Grolleg Kaolin 55
Potash Feldspar 25
Flint 15
Bentonite 5
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Ellen Currans on sat 17 oct 09
May, the same recipe is listed in a monograph on David Leach from l977,=3D2=
0
with the following notes.
"Different qualities of materials will affect the performance of the=3D20
body. ECC Standard Porcelain China
Clay is probably the best (and the most expensive). Grollegg is also=3D20
recommended. But the differences
are marginal and the commercially made-up body, which uses neither of=3D20
these clays, is still acceptable. The
Bentonite is the most difficult to find: it must be low in iron, and=3D20
the current Berkonite is imported by Berk
Minerals from the island of Ponza, just outside the bay of Naples. It=3D20
is volcanic in origin and very pure."
I have something called GK129, White Bentonite. I wonder if that would=3D2=
0
be a good substitute for the
Berkonite? I don't do porcelain so I really don't know anything about=3D20
this.
Ellen Currans
Dundee, Oregon
-----Original Message-----
From: Lee Love
To: Clayart@LSV.CERAMICS.ORG
Sent: Sat, Oct 17, 2009 6:24 am
Subject: Re: bone china and porcelain
On Fri, Oct 16, 2009 at 10:37 PM, May Luk wrote:
> Dinah;
> Do you have the David Leach Porcelain recipe?
From the archives, found on Google:
David Leach Porcelain Cone 10 reduction
Grolleg Kaolin 55
Potash Feldspar 25
Flint 15
Bentonite 5
--
Lee, a Mashiko potter in Minneapolis
http://mashikopots.blogspot.com/
"Ta tIr na n-=3DC3=3DB3g ar chul an tI=3DE2=3D80=3D94tIr dlainn trina ch=
=3DC3=3DA9ile"=3D
=3DE2=3D80=3D94that is, "The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Dinah Snipes Steveni on sat 17 oct 09
Hi May=3D20
I will look out for the Leach porcelain recipe for you. Actually, if you wi=
=3D
sh, and it seemed a bit harsh and stupid=3DC2=3DA0on rereading my post=3DC2=
=3DA0on =3D
sharing in general-- I will send you the Lucie Rie porcelain body recipes a=
=3D
s well. Now bear in mind that she once-fired to 1250 Centigrade. Hence they=
=3D
are a bit kaolin heavy. I've no idea of her firing schedule. That's to be =
=3D
tested, but=3DC2=3DA0can tell you what I did. And in retrospect I think my =
heat=3D
work on hold probably pushed the temps up too high. I am going to use cone=
=3D
s more faithfully. I'm away from=3DC2=3DA0journals and references=3DC2=3DA0=
at the m=3D
oment -- my gallery sitting shift at Gallery North in Edmonds as co-op.=3D2=
0
Dinah=3D20
claybuds@ATT.NET on sat 17 oct 09
=3DC2=3DA0
Ellen,
=3DC2=3DA0Be sure to fire a fusion button of any bentonite that you may th=
ink =3D
fires white. Many bentonites fire chocolate brown and are loaded with iron.=
=3D
The only white burning bentonite-like product that actually fires white en=
=3D
ough to be used in a porcelain body=3DC2=3DA0that=3DC2=3DA0I've=3DC2=3DA0be=
en=3DC2=3DA0able=3D
=3DC2=3DA0to=3DC2=3DA0find is known as Bentone MA (I assume MA means Macal=
oid). Ve=3D
egum T also fires as white, but doesn't lend the plasticity that Bentone is=
=3D
capable of, particularly if you add it to=3DC2=3DA0hot water and allow it =
to s=3D
oak.
David Beumee
-------------- Original message from Ellen Currans : -=
=3D
-------------=3D20
> May, the same recipe is listed in a monograph on David Leach from l977,=
=3D
=3D20=3D20
> with the following notes.=3D20
>=3D20=3D20
> "Different qualities of materials will affect the performance of the=3D20=
=3D
=3D20
> body. ECC Standard Porcelain China=3D20
> Clay is probably the best (and the most expensive). Grollegg is also=3D2=
0=3D
=3D20
> recommended. But the differences=3D20
> are marginal and the commercially made-up body, which uses neither of=3D2=
0=3D
=3D20
> these clays, is still acceptable. The=3D20
> Bentonite is the most difficult to find: it must be low in iron, and=3D2=
0=3D
=3D20
> the current Berkonite is imported by Berk=3D20
> Minerals from the island of Ponza, just outside the bay of Naples. It=3D=
20=3D
=3D20
> is volcanic in origin and very pure."=3D20
>=3D20=3D20
> I have something called GK129, White Bentonite. I wonder if that would=
=3D
=3D20=3D20
> be a good substitute for the=3D20
> Berkonite? I don't do porcelain so I really don't know anything about=3D=
20=3D
=3D20
> this.=3D20
>=3D20=3D20
> Ellen Currans=3D20
> Dundee, Oregon=3D20
>=3D20=3D20
>=3D20=3D20
> -----Original Message-----=3D20
> From: Lee Love=3D20
> To: Clayart@LSV.CERAMICS.ORG=3D20
> Sent: Sat, Oct 17, 2009 6:24 am=3D20
> Subject: Re: bone china and porcelain=3D20
>=3D20=3D20
>=3D20=3D20
>=3D20=3D20
>=3D20=3D20
>=3D20=3D20
>=3D20=3D20
> On Fri, Oct 16, 2009 at 10:37 PM, May Luk wrote:=3D20
> > Dinah;=3D20
> > Do you have the David Leach Porcelain recipe?=3D20
>=3D20=3D20
> From the archives, found on Google:=3D20
>=3D20=3D20
> David Leach Porcelain Cone 10 reduction=3D20
>=3D20=3D20
> Grolleg Kaolin 55=3D20
> Potash Feldspar 25=3D20
> Flint 15=3D20
> Bentonite 5=3D20
>=3D20=3D20
> --=3D20
> Lee, a Mashiko potter in Minneapolis=3D20
> http://mashikopots.blogspot.com/=3D20
>=3D20=3D20
> "Ta tIr na n-=3DC3=3DB3g ar chul an tI=3DE2=3D80=3D94tIr dlainn trina ch=
=3DC3=3DA9ile"=3D
=3DE2=3D80=3D94that is, "The=3D20
> land of eternal youth is behind the house, a beautiful land fluent=3D20
> within itself." -- John O'Donohue
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