Michael Pressman on sun 18 nov 07
I've been using Standard Cone 6 Porcelain and am quite happy with some
glazes I've found to use with it. But it's really horrible to throw, so I
want to try using it as a slip on some Cone 6 stoneware.
Should I simply mix the porcelain with water and use that as a slip?
Do I need to add anything to it?
Or, am I better off mixing a slip from scratch..and if so, any recommendation?
I have very little experience with slips.
Thanks
Michael
Fredrick Paget on mon 19 nov 07
>I've been using Standard Cone 6 Porcelain and am quite happy with some
>glazes I've found to use with it. But it's really horrible to throw, so I
>want to try using it as a slip on some Cone 6 stoneware.
Michael
--
I have in the past made slip out of just about any clay I had in the
scrap bucket . That has included porcelain and many other clays as I
am an experimenter and try a lot of different things.
That slip is never as good as a real slip clay formula but can work.
It usually takes a lot longer to set up in the mold to the proper
thickness but after it does and you pour out the excess in the mold
and let it shrink it works.
Do not try to make slip from soft clay. Dry it into bone dry state
and break it up into small pieces. Then put it into water with
deflocculant in it . Use a minimum of water and let it sit
undisturbed overnight until it slakes down.
Pour off all excess water and use a drill with a mixer on a shaft to
stir it until it is amooth and put it through a screen using a stiff
brush to make it go through.
Fred
Twin Dragon Studio
Mill Valley, CA, USA
fredrick@well.com
Charter Member Potters Council
John Rodgers on mon 19 nov 07
Michael,
Not to discourage, BUT -
I do a lot of slip casting, and I have tried the Standard cone 6 -
bought it dry bagged - but I found it very difficult to make a decent
slip from - and I make up slip from dry bagged clay all the time. I also
tried Grolleg the same way - same problem. I use a lot of Laguna C-5
B-mix throwing clay for my throwing work - and it does not make a good
casting slip either. BUT, I also use Laguna's C-5 B-mix slip clay dry
bagged and mix it on site. It works beautifully. Laguna tells me that
the dry bagged is just a tiny bit different - ball clay amount I think -
than the moist throwing version. They told me that that difference in
ball clay is what makes it really work a a slip casting clay. I decided
to stick with the Laguna B-mix - slip and moist clays - because they
were so close you could make pieces and parts from each and join them
together into uique forms, and not have differential shrinking
problems. Works great.
But as for the Standard or the Grolleg - I never got those to work. I
think there simply must be an adjustment in the ratios of clays to make
it work. Otherwise you are stuck with buying ready made, ready to pour,
porcelain slip. And I really hate having to pay for all that water to be
shipped. than is in the slip.
If you can find a good porcelain recipe, making your own from scratch
would definitely be the way to go. I used to mix slip casting clays
bodies from scratch in 500 gallon lots. Worked great. So scratch built
clay bodies are feasible.
Regards,
John Rodgers
Chelsea, AL
Michael Pressman wrote:
> I've been using Standard Cone 6 Porcelain and am quite happy with some
> glazes I've found to use with it. But it's really horrible to throw, so I
> want to try using it as a slip on some Cone 6 stoneware.
>
> Should I simply mix the porcelain with water and use that as a slip?
> Do I need to add anything to it?
> Or, am I better off mixing a slip from scratch..and if so, any recommendation?
>
> I have very little experience with slips.
>
> Thanks
>
> Michael
>
> ______________________________________________________________________________
> 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
>
>
>
Veena Raghavan on mon 19 nov 07
Michael,
If you have access to Highwater clays, their P-5 porcelain, which fires to
Cone 6, is a very nice throwing and handbuilding clay. I have been using it for
several years with good results. I really enjoy throwing with it. I would much
rather use it than a stoneware with a porcelain slip.
All the best.
Veena
In a message dated 11/19/2007 2:05:54 PM Eastern Standard Time,
mnpress@GMAIL.COM writes:
>
> I've been using Standard Cone 6 Porcelain and am quite happy with some
> glazes I've found to use with it. But it's really horrible to throw, so I
> want to try using it as a slip on some Cone 6 stoneware.
>
VeenaRaghavan@cs.com
Michael Pressman on mon 19 nov 07
(I tried posting this yesterday, but it did not appear on the list)
I've been using Standard Cone 6 Porcelain and am quite happy with some
glazes I've found to use with it. But it's really horrible to throw, so I
want to try using it as a slip on some Cone 6 stoneware.
Should I simply mix the porcelain with water and use that as a slip?
Do I need to add anything to it?
Or, am I better off mixing a slip from scratch..and if so, any
recommendation?
I have very little experience with slips.
Thanks
Michael
claystevslat on tue 20 nov 07
Michael -- You've gotten lots of responses, but many
folks seem to have read your post as an inquiry into
slip casting. I know I read it, originally, as a
question about applying porcelain slip to stoneware,
presumably to get porcelain color-response on a
thrown stoneware piece.
If I was wrong, ignore this message ...
I did this a few times with slip that was just water
and clay (whipped up with a drill and strained
2x for consistency) and it worked just fine. I
brushed it on to still-damp stoneware, and the only
issue I had was that when I trimmed, I exposed raw
stoneware (duh).
If I trimmed first, brushing didn't work so well
(the drag on the brush was an issue, and applying
a consistent 'skin' of porcelain slip was difficult.)
Dipping in a bowl of thinned slip worked OK,
though. I have recently added glycerine to a few
things for brushing (not slip) and found it helps
with consistent brushing results. It might help
with the drag issue.
Best -- Steve S
--- In clayart@yahoogroups.com, Michael Pressman wrote:
>
> (I tried posting this yesterday, but it did not appear on the list)
>
> I've been using Standard Cone 6 Porcelain and am quite happy with
some
> glazes I've found to use with it. But it's really horrible to
throw, so I
> want to try using it as a slip on some Cone 6 stoneware.
>
> Should I simply mix the porcelain with water and use that as a slip?
> Do I need to add anything to it?
> Or, am I better off mixing a slip from scratch..and if so, any
> recommendation?
>
> I have very little experience with slips.
>
> Thanks
>
> Michael
Michael Pressman on wed 21 nov 07
Steve,
Yes, that's exactly what I'm trying to do-just get porcelain glaze results
on thrown stoneware. Sorry if I wasn't clear in my original post. And
thanks, I will try your suggestion.
I should also clarify my throwing issues with the cone 6 porcelain. It's
fine for throwing small stuff, but I particularly enjoy throwing very large
bowls--15-20 pounds of clay. And I have a lot of trouble doing that with
the cone 6 porcelain. I used to have access to a gas reduction kiln, so I
always used to throw stoneware. But now that I'm firing exclusively in an
electric kiln in my home, I haven't been able to get excited about any
glazes on stoneware.
Thanks all for your replies.
Michael
Lynn Goodman Porcelain Pottery on thu 22 nov 07
On Nov 21, 2007, at 10:40 AM, Michael Pressman wrote:
> I should also clarify my throwing issues with the cone 6
> porcelain. It's
> fine for throwing small stuff, but I particularly enjoy throwing
> very large
> bowls--15-20 pounds of clay. And I have a lot of trouble doing
> that with
> the cone 6 porcelain. I used to have access to a gas reduction
> kiln, so I
> always used to throw stoneware. But now that I'm firing
> exclusively in an
> electric kiln in my home, I haven't been able to get excited about any
> glazes on stoneware.
Hi Michael,
I'm curious which ^6 porcelain you tried. I throw the Standard 551
and find it very easy to work with. (I've also tried several other
porcelains-- different brands and different mixes; I hated them.)
Lynn
Lois Ruben Aronow on thu 22 nov 07
Standard makes 3 ^6 porcelain bodies. Just curious which one is troubling
you.
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of
> Michael Pressman
> Sent: Wednesday, November 21, 2007 10:41 AM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Cone 6 Porcelain Slip
>
> Steve,
>
> Yes, that's exactly what I'm trying to do-just get porcelain
> glaze results on thrown stoneware. Sorry if I wasn't clear
> in my original post. And thanks, I will try your suggestion.
>
> I should also clarify my throwing issues with the cone 6
> porcelain. It's fine for throwing small stuff, but I
> particularly enjoy throwing very large bowls--15-20 pounds of
> clay. And I have a lot of trouble doing that with the cone 6
> porcelain. I used to have access to a gas reduction kiln, so
> I always used to throw stoneware. But now that I'm firing
> exclusively in an electric kiln in my home, I haven't been
> able to get excited about any glazes on stoneware.
>
> Thanks all for your replies.
>
> Michael
>
> ______________________________________________________________
> ________________
> 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
claystevslat on thu 22 nov 07
Hi, Kathryn --
There are particular issues with all clays. Certain shapes
are especially difficult with porcelain -- I've had lots
of problems with larger platters deforming, for example.
Often the solution is just to switch clays. But let's
say I find that Bennett Clay (Tacoma Clay Arts, a light
colored stoneware that has excellent thermal shock
properties and can be used as ovenware) makes a perfect
casserole, but someone who really wants to have me make
a casserole for them also wants a really 'bright' version
of Veena Raghaven's Chun-like Green, and that glaze over
Bennett looks like snail snot from satan? (Well, it's
not actually quite that bad, but it ain't good.)
I can throw the casserole body and lid from Bennett,
get the stability, strength, and oven-ware durability
that I want, and by 'painting' a thin coat of a
porcelainous slip over the Bennett, get a base
for the glaze that will provide the color my client
wants.
It won't get you the translucency of actual porcelain,
but it's a good work-around for some purposes. And you
still have to test, not all slips will adhere well
and dry without cracking over all clays. But if you
have a slip that works right and a clay that works right,
it's worth a shot.
Best wishes -- Steve S
--- In clayart@yahoogroups.com, sacredclay wrote:
>
> I'm curious. Instead of dipping the whole bowl in white slip, why
not
> just work with white clay? Especially if one doesn't want the raw
> clay underneath exposed.I always love to hear from you. Kathryn
> Hughes>
sacredclay on thu 22 nov 07
I'm curious. Instead of dipping the whole bowl in white slip, why not
just work with white clay? Especially if one doesn't want the raw
clay underneath exposed.I always love to hear from you. Kathryn
Hughes>
> I did this a few times with slip that was just water
> and clay (whipped up with a drill and strained
> 2x for consistency) and it worked just fine. I
> brushed it on to still-damp stoneware, and the only
> issue I had was that when I trimmed, I exposed raw
> stoneware (duh).
>
> If I trimmed first, brushing didn't work so well
> (the drag on the brush was an issue, and applying
> a consistent 'skin' of porcelain slip was difficult.)
>
> Dipping in a bowl of thinned slip worked OK,
> though. I have recently added glycerine to a few
> things for brushing (not slip) and found it helps
> with consistent brushing results. It might help
> with the drag issue.
>
> Best -- Steve S
>
>
Michael Pressman on fri 23 nov 07
Lynn, This is interesting... I've been using Standard 213.. was not
particularly aware of 551...is it nicer to throw? Is it as white?
Thanks
Michael
Carole Fox on fri 23 nov 07
Lynn-
I also have tried many cone six porcelains and I have not found any that
will make large work without slumping.
My favorite is Standard 551, but it will not hold up at cone 6 (or even 5 )
as large bowls.
So, like Michael, I use stoneware now for all large work. I wish I could
find a cone 6 porcelain that would hold up when working big!
Carole Fox
Silver Fox Pottery
Elkton, MD
silverfoxpottery@comcast.net
>
> I'm curious which ^6 porcelain you tried. I throw the Standard 551
> and find it very easy to work with. (I've also tried several other
> porcelains-- different brands and different mixes; I hated them.)
>
> Lynn
June Perry on fri 23 nov 07
Lynn,
Why don't you try adding porcelain grog (molochite) to your body for taller
pieces. You can just wedge it in. Try 5-7% of what would be the dry weight of
the clay.
It can also help, when throwing porcelain, to not let the water or slip sit
on the pot too long while throwing, so keep ribbing it off with a metal rib
as you throw. That may also help with the slumping problem.
Regards,
June
_http://www.shambhalapottery.com_ (http://www.shambhalapottery.com/)
_http://shambhalapottery.blogspot.com_
(http://shambhalapottery.blogspot.com/)
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Lynn Goodman Porcelain Pottery on sat 24 nov 07
On Nov 23, 2007, at 9:34 AM, Carole Fox wrote:
> Lynn-
> I also have tried many cone six porcelains and I have not found any
> that
> will make large work without slumping.
>
> My favorite is Standard 551, but it will not hold up at cone 6 (or
> even 5 )
> as large bowls.
>
> So, like Michael, I use stoneware now for all large work. I wish I
> could
> find a cone 6 porcelain that would hold up when working big!
> Carole Fox
> Silver Fox Pottery
> Elkton, MD
> silverfoxpottery@comcast.net
How big are you working? I throw bowls to a 20 inch diameter fairly
frequently--I've had no problem with it.
Lynn
Lynn Goodman Porcelain Pottery on sat 24 nov 07
On Nov 23, 2007, at 1:40 PM, Michael Pressman wrote:
> Lynn, This is interesting... I've been using Standard 213.. was not
> particularly aware of 551...is it nicer to throw? Is it as white?
>
> Thanks
>
> Michael
It's much whiter. I find it far easier to throw than the 213. For
some reason which I cannot fathom, Standard doesn't push this clay
like they do their others. They should!
Lynn
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
Chris Campbell on sat 24 nov 07
Carole Fox wrote ...
> I also have tried many cone six porcelains
> and I have not found any that will make large
> work without slumping.
> ..... I wish I could find a cone 6 porcelain that
would hold up when working big!
One of the firing properties of porcelain is
that it has to be supported during high firing or
it will slump ... once the form goes out beyond
the foundation, it needs help.
This is why porcelain makers fire high first,
then glaze and fire low.
Most porcelain books detail several ways to
support your work during firing.
If you add grog to the clay, it is not
really porcelain anymore ...
Chris Campbell - in North Carolina
Chris Campbell Pottery LLC
9417 Koupela Drive
Raleigh NC 27615-2233
Designs in Colored Porcelain
1-800-652-1008
Fax : 919-676-2062
website: www.ccpottery.com
wholesale : www.wholesalecrafts.com
Lois Ruben Aronow on sun 25 nov 07
I use both, and am probably going back to using the 551 exclusively.
the 213 is more yellow, and more like stoneware. The 551 is divine, but it
has 2 downsides:
1. it warps like crazy
2. it costs 30% more than the 213. (I use the 213 on work that I cover in
black underglaze. My white work is always 551.)
There is a third body - 365. that one is the most beautiful after firing.
it's parian and vitreous. it's also not very good for bigger wares, IMHO.
for anyone looking for a Miller/Laguna option, I am so in love with #15. it
costs a bit more than the Standard 551, but it throws like a dream, dries
like a dream, feels delightful....
> -----Original Message-----
> From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of
> Lynn Goodman Porcelain Pottery
> Sent: Saturday, November 24, 2007 10:07 AM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Cone 6 Porcelain Slip
>
> On Nov 23, 2007, at 1:40 PM, Michael Pressman wrote:
>
> > Lynn, This is interesting... I've been using Standard
> 213.. was not
> > particularly aware of 551...is it nicer to throw? Is it as white?
> >
> > Thanks
> >
> > Michael
>
> It's much whiter. I find it far easier to throw than the 213.
> For some reason which I cannot fathom, Standard doesn't push
> this clay like they do their others. They should!
>
> Lynn
>
>
> Lynn Goodman
> Fine Porcelain Pottery
> Cell 347-526-9805
> www.lynngoodmanporcelain.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
Carole Fox on mon 26 nov 07
To clarify- the bowls are slumping in the glaze fire- not in the throwing.
Carole Fox
Silver Fox Pottery
Elkton, MD
silverfoxpottery@comcast.net
Carole Fox on mon 26 nov 07
Now this is strange. I make big bowls from the same clay as Lynn. Mine slump
and hers don't.
I have broken my slumped bowls to see if they had a thin spot but they
looked fine.
What am I doing wrong?
Carole Fox
Silver Fox Pottery
Elkton, MD
silverfoxpottery@comcast.net
Lynn Goodman Porcelain Pottery on mon 26 nov 07
On Nov 26, 2007, at 8:29 AM, Carole Fox wrote:
> Now this is strange. I make big bowls from the same clay as Lynn.
> Mine slump
> and hers don't.
>
> I have broken my slumped bowls to see if they had a thin spot but they
> looked fine.
>
> What am I doing wrong?
You may need to move the foot ring further out. You may also need to
handle the bowl less--once it starts to stiffen up, the clay will
remember every little thing you do to it!
Lynn
Lynn Goodman
Fine Porcelain Pottery
Cell 347-526-9805
www.lynngoodmanporcelain.com
June Perry on mon 26 nov 07
You might be starting with softer clay, or you might be taking longer to
throw, therefore putting more water into the clay.
Try to not leave water sitting on the vertical face of the pot any longer
than necessary. Use a metal rib to remove it as you throw. Try to be a bit more
aggressive and dig in more on the first one or two pulls which will help you
get the pot thinner without having to make too many more pulls.
Another thing you might try to do, and this takes practice, is to try to
throw dry. After you center and open with your normal amount of water, try using
no water or very little. It takes practice but you will eventually get the
sensitivity to when the clay wants to pull and you can ease up.
Regards,
June
_http://www.shambhalapottery.com_ (http://www.shambhalapottery.com/)
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Ron Roy on wed 28 nov 07
Hi Carol,
Most porcelain gets softer than stoneware at the end of a firing. You have
to allow for that by shaping in such a way as to transfer weight downward
in a more even way. Think of an upside down arch for bowls for instance.
You need to compare cone bend with the others who are using the same clay
as well - porcelain melts faster - has a lot of flux compared to stoneware
- so when the melting finally starts it goes fast.
Not every batch of clay is fluxed the same - some clay companies have
better controls in place then others for instance - or use more reliable
materials.
You are right to look at evenness - very often the slump will be due to an
over trimmed part. You also need to look at overall thinness when comparing
with others - maybe compare weight.
Got any pictures to send me? Of slumped ware - and some not slumped to compare.
RR
>To clarify- the bowls are slumping in the glaze fire- not in the throwing.
>Carole Fox
>Silver Fox Pottery
>Elkton, MD
>silverfoxpottery@comcast.net
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Bill Merrill on wed 28 nov 07
One thing about porcelain is if your kiln fires too long at the fluxed
end of a firing the clay body shape can deform. For example if you have
a handle on an open cup, the cup may have gone into the glaze firing
round and come out as an ellipse. One thing I have used in a porcelain
body is pyrophyllite (pyrotrol). This makes the porcelain stronger. It
is used in tile bodies also. Have you tried using it in a clay body?
Bill
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ron Roy
Sent: Wednesday, November 28, 2007 3:36 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Cone 6 Porcelain Slip
Hi Carol,
Most porcelain gets softer than stoneware at the end of a firing. You
have
to allow for that by shaping in such a way as to transfer weight
downward
in a more even way. Think of an upside down arch for bowls for instance.
You need to compare cone bend with the others who are using the same
clay
as well - porcelain melts faster - has a lot of flux compared to
stoneware
- so when the melting finally starts it goes fast.
Not every batch of clay is fluxed the same - some clay companies have
better controls in place then others for instance - or use more reliable
materials.
You are right to look at evenness - very often the slump will be due to
an
over trimmed part. You also need to look at overall thinness when
comparing
with others - maybe compare weight.
Got any pictures to send me? Of slumped ware - and some not slumped to
compare.
RR
>To clarify- the bowls are slumping in the glaze fire- not in the
throwing.
>Carole Fox
>Silver Fox Pottery
>Elkton, MD
>silverfoxpottery@comcast.net
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
________________________________________________________________________
______
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
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