Lesley Alexander on tue 20 may 03
>
> I have seen paper clay used for sculpture, tiles etc.but is anyone using
it
> for functional pieces? I was thinking about using it for cups, large
> platters and bowls. How will this stand up to everyday use? What about
> permeability, and all those other issues we have to consider? Thanks
> Lari Ward
Lari, a real test would be to make bars of plain clay and paper clay and see
how much pressure would be required to break them. It appears to glaze and
hold up as well as regular clay.... and is lighter. Very nice for things
like 18" to 20" trays with handles. What experience have others had?
Lari Ward on tue 20 may 03
Hello all,
I have seen paper clay used for sculpture, tiles etc.but is anyone using it
for functional pieces? I was thinking about using it for cups, large
platters and bowls. How will this stand up to everyday use? What about
permeability, and all those other issues we have to consider? Thanks
Lari Ward
Ababi on wed 21 may 03
When I got from Ron Roy the stickiest rules of glazing - I had sadly to except
his words about paperclay.
The tiny microscopic holes left in the claybody might absorb the humidity from
repeating daily washings. Your ware will turn ugly from the inside.
My compromise: fruit bawls, tray- sometimes. any ware that will not have to see your
dish washer too often or better at all.
About paperclay :
http://members4.clubphoto.com/ababi306910/803792/
Similar in Hebrew
http://members4.clubphoto.com/ababi306910/839502/
Can here too: When Vika made here cup I thought paperclay can be used for food
servicing dishes too.
Ron's letter is the reason that her last works, the tea pot and the last tray are made
out of regular claybody
http://members4.clubphoto.com/ababi306910/797099/
The students in this group do not want to her about anything but paperclay the only
work that is not paperclay is ( Gad1)
http://members4.clubphoto.com/ababi306910/1195866/
---------- Original Message ----------
>Hello all,
>I have seen paper clay used for sculpture, tiles etc.but is anyone using it
>for functional pieces? I was thinking about using it for cups, large
>platters and bowls. How will this stand up to everyday use? What about
>permeability, and all those other issues we have to consider? Thanks
>Lari Ward
Ababi on wed 21 may 03
>Lari, a real test would be to make bars of plain clay and paper clay and see
>how much pressure would be required to break them. It appears to glaze and
>hold up as well as regular clay.... and is lighter. Very nice for things
>like 18" to 20" trays with handles. What experience have others had?
=========================================
Hello Lesley&Lari
The best test is as written in J& R book test for absorption!
Ababi
Ron Roy on wed 21 may 03
Hi Lary,
Won't work - when the paper burns out it leaves channels - they will leak
and absorb water - particularly dangerous in a microwave oven.
RR
>
>I have seen paper clay used for sculpture, tiles etc.but is anyone using it
>for functional pieces? I was thinking about using it for cups, large
>platters and bowls. How will this stand up to everyday use? What about
>permeability, and all those other issues we have to consider? Thanks
>
>
>
>Lari Ward
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Cate Loveland on wed 21 may 03
RR says paper clay not good for functional wares because the paper burns out
and leaves channels..which is true, but isn't that what glazing is for? The
correct glaze should melt and fill in all those little channels and create an
impervious surface, just like any other clay body. I think.
Cate in AZ
LindaBlossom on wed 21 may 03
A thought on this....when I decreased the grog in my clay body to 5% (a
paperclay body) the clay was so tight when fired that it was not porous
enough for outdoor freeze thaw use. It was just too tight. My thought was
that the paper burned out long before the clay began to really shrink in the
firing and the channels just aren't there. Now grog...there you have
channels because the clay shrinks away from the grog leaving little
spaces...
Linda
Ithaca, NY
> Hi Lary,
>
> Won't work - when the paper burns out it leaves channels - they will leak
> and absorb water - particularly dangerous in a microwave oven.
>
> RR
> >
> >I have seen paper clay used for sculpture, tiles etc.but is anyone using
it
> >for functional pieces? I was thinking about using it for cups, large
> >platters and bowls. How will this stand up to everyday use? What about
> >permeability, and all those other issues we have to consider? Thanks
> >
> >
> >
> >Lari Ward
>
L. P. Skeen on wed 21 may 03
----- Original Message -----
From: "Lari
> > > >I have seen paper clay used for sculpture, tiles etc.but is anyone
using
> it for functional pieces? I was thinking about using it for cups, large
> > >platters and bowls.
Lari,
I have been using it just fine, no problem, but RR says no, so I suggest you
do RR's very own absorption test. You'll have to ask him for the
particulars, but it involves making a test bar and firing to glaze temp,
then weighing dry, then boiling in water for x number time, then weighing
again to see how much water it absorbed in the process. After you've done
THAT, then you can take said test bar and do a freeze/thaw test to see how
durable it is. Freeze the sucker, then take it out and drop in boiling
water. If it don't break, good ups! :)
L
Susan Setley on wed 21 may 03
In a message dated 5/21/03 7:05:14 PM, lindablossom@ATT.NET writes:
<< A thought on this....when I decreased the grog in my clay body to 5% (a
paperclay body) the clay was so tight when fired that it was not porous
enough for outdoor freeze thaw use. It was just too tight. My thought was
that the paper burned out long before the clay began to really shrink in the
firing and the channels just aren't there. Now grog...there you have
channels because the clay shrinks away from the grog leaving little
spaces...
Linda >>
I have seen sources on line talking about paper clay stating that the reason
paperclay is so strong is that the cellulose fibers burn off early and are
filled with clay in the channels left behind, like little structural supports.
Ron Roy on thu 22 may 03
Hi Linda,
The reason I know that paper increases absorption - Tuckers does several of
their stock bodies with paper. They test all their batches of clay for
shrinkage and absorption - in every case - at all temperatures - the
absorption is always more for the clay with paper. In other words more
water gets in.
This means the ware will be unsuitable for microwaving as it will heat up.
As to glaze sealing the clay - - I would say maybe some times but there are
often imperfections in the glaze which will let water through - and surely
if the glaze crazes the ware will leak.
If water can get in under the glaze (through the foot) it will sometimes
cause crazing - through rehydration over time.
I have to go out of town for a few days and I'm in a rush right now - I'll
send the absorption tests next Wed Lisa.
I'm gone!
RR
>A thought on this....when I decreased the grog in my clay body to 5% (a
>paperclay body) the clay was so tight when fired that it was not porous
>enough for outdoor freeze thaw use. It was just too tight. My thought was
>that the paper burned out long before the clay began to really shrink in the
>firing and the channels just aren't there. Now grog...there you have
>channels because the clay shrinks away from the grog leaving little
>spaces...
>Linda
>Ithaca, NY
>> Hi Lary,
>> Won't work - when the paper burns out it leaves channels - they will leak
>> and absorb water - particularly dangerous in a microwave oven.
>> RR
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
LindaBlossom on thu 22 may 03
> In a message dated 5/21/03 7:05:14 PM, lindablossom@ATT.NET writes:
>
> << A thought on this....when I decreased the grog in my clay body to 5% (a
>
> paperclay body) the clay was so tight when fired that it was not porous
>
> enough for outdoor freeze thaw use. It was just too tight. My thought
was
>
> that the paper burned out long before the clay began to really shrink in
the
>
> firing and the channels just aren't there. Now grog...there you have
>
> channels because the clay shrinks away from the grog leaving little
>
> spaces...
>
>
> Linda >>
>
> I have seen sources on line talking about paper clay stating that the
reason
> paperclay is so strong is that the cellulose fibers burn off early and are
> filled with clay in the channels left behind, like little structural
supports.
These fibers are sooo small, I doubt this but then I am open to solid
information that supports it. I have made many slab built plates and they
are as strong as anything I have bought. No chipping or breaking. Remember
that paper clay has fibers, not lumps of cellulouse. It simply is not true
that it has no structural integrity. Good grief, I have made pedestals and
sinks from this without problems.
Linda
Ithaca, NY
LindaBlossom on thu 22 may 03
Ron,
I can't answer for other clay bodies...but is increased absorption the same
as too much absorption? Low fire ware has great absorption, and inherent
weakness. At least in my experience of broken and chipped ware I have used,
but it is still used. A stoneware clay that already has low absorption with
added paper fibers - is it necessarily too porous to use? I am not
disagreeing but my experience is when it comes to using my own body.
Linda
Ithaca, NY
> The reason I know that paper increases absorption - Tuckers does several
of
> their stock bodies with paper. They test all their batches of clay for
> shrinkage and absorption - in every case - at all temperatures - the
> absorption is always more for the clay with paper. In other words more
> water gets in.
>
> This means the ware will be unsuitable for microwaving as it will heat up.
>
> As to glaze sealing the clay - - I would say maybe some times but there
are
> often imperfections in the glaze which will let water through - and surely
> if the glaze crazes the ware will leak.
>
> If water can get in under the glaze (through the foot) it will sometimes
> cause crazing - through rehydration over time.
>
> I have to go out of town for a few days and I'm in a rush right now - I'll
> send the absorption tests next Wed Lisa.
>
> I'm gone!
>
> RR
>
> >A thought on this....when I decreased the grog in my clay body to 5% (a
> >paperclay body) the clay was so tight when fired that it was not porous
> >enough for outdoor freeze thaw use. It was just too tight. My thought
was
> >that the paper burned out long before the clay began to really shrink in
the
> >firing and the channels just aren't there. Now grog...there you have
> >channels because the clay shrinks away from the grog leaving little
> >spaces...
> >Linda
> >Ithaca, NY
> >> Hi Lary,
> >> Won't work - when the paper burns out it leaves channels - they will
leak
> >> and absorb water - particularly dangerous in a microwave oven.
> >> RR
Gail Dapogny on thu 22 may 03
From time to time, we have discussed on this list various safety problems
that we know about. Sometimes it makes shudder when I think about how they
may catch up with us sometime in the future if we ignore problems. That
is, the public will finally discover that we are all too often ignorant and
careless about our materials and how we use them.
It's one thing to use experimental things in non-functional pieces, and
quite another to stick them in functional ware. The public is learning
about lead and some even know that barium in some glazes is a problem. But
they sure don't know about non-vitrified clay in vases, color fade, pieces
that could blow up in the microwave or crack in the oven, etc. etc, in
other words, problems that are the result of our ignoring very real
potential dangers, and playing wide-eyed and dumb.
I don't mean Lari. She is to be commended for asking about this rather
than just plunging in. I don't mean anyone in particular.
But let's keep exploring these things, and heeding advice from people like
Ron who is thoughtful and knowledgeable about so much, and is anything but
an alarmist.
Gail Dapogny in Ann Arbor
>> Won't work - when the paper burns out it leaves channels - they will leak
>> and absorb water - particularly dangerous in a microwave oven.
>>
>> RR
>> >
>> >I have seen paper clay used for sculpture, tiles etc.but is anyone using
it for functional pieces? I was thinking about using it for cups, large
platters and bowls. How will this stand up to everyday use? What about
permeability, and all those other issues we have to consider? Thanks
>> >Lari Ward
Tom Sawyer on thu 22 may 03
I've been using a mix of 1/2 paper clay and 1/2 good stoneware throwing
clay for about the last 6 months. I'm doing a lot of sectional pottery
and believe that the joins are more certain and that cracking has all
but been eliminated. I've found that throwing with just paper clay is
more difficult [not impossible]. Since I alternate between hand building
and throwing this combination is working nicely for me.
Tom Sawyer
tsawyer@cfl.rr.com
Susan Setley on thu 22 may 03
In a message dated 5/22/03 5:18:58 AM, lindablossom@ATT.NET writes:
<< Remember
that paper clay has fibers, not lumps of cellulouse. It simply is not true
that it has no structural integrity. Good grief, I have made pedestals and
sinks from this without problems.
>>
Yes it does. The picture I'm getting is that it is incredibly strong for
constructing pieces from clay but susceptible to water absorbtion over time. This
wouldn't be a problem with a pedestal or sink because they typically don't go
in the microwave or oven.
I haven't used it yet but have a project in mind its structural properties
would be good for.
Susan Setley on thu 22 may 03
In a message dated 5/22/03 5:18:58 AM, lindablossom@ATT.NET writes:
<<
These fibers are sooo small, I doubt this but then I am open to solid
information that supports it. >>
I can't give you that. I read it at the sales site. It would be to the
manufacturer's interest to put the idea through.
Fabienne Micheline Cassman on thu 22 may 03
This reminds me of a conversation I had with RR at NCECA about P'clay. I had forgotten to mention that I had intended it for non-functional pieces. The first words out of his mouth was "it leaks." LOL I was thrown off with my mind geared as it was. I gather that unless you are planning on a prank, it's not the clay for functional ware.
I was also warned by another person that the trimming is not trivial since you have paper fibers to deal with and they are quite tough.
Cheers,
Fabienne
--
Fabienne Cassman http://www.milkywayceramics.com/
WARNING: I cannot be held responsible for the above
because my cats have apparently learned to type.
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Janet Kaiser on thu 22 may 03
I get to see the work of many functional potters, but I have never seen
them use paperclay, Lari. There has to be a certain "integrity" to a clay
body used for functional work, which most paperclay simply does not
possess.
It is perfectly good for making large (and small) work which is sculptural
(or even "occasionally" functional such as large fruit bowls) but is
certainly not being used day-in, day-out. No washing up, no stacking,
moving around, hot and cold treatment. Paperclay is not usually a "strong"
enough body for daily ware and tear IMO and I would be very even more
cautious about mugs, cups and teapots... Indeed, anything which would hold
hot liquids and could become weakend through long-term use.
Sincerely
Janet Kaiser
*** IN REPLY TO THE FOLLOWING MAIL:
>I have seen paper clay used for sculpture, tiles etc.but is anyone using
it
>for functional pieces? I was thinking about using it for cups, large
>platters and bowls. How will this stand up to everyday use? What about
>permeability, and all those other issues we have to consider? Thanks
>Lari Ward
*** THE MAIL FROM Lari Ward ENDS HERE ***
**********************************************************************
TRUTH is too precious to tell every fool who asks for it...
****** This post was sent to you today by Janet Kaiser *******
The Chapel of Art / Capel Celfyddyd
8 Marine Crescent, Criccieth LL52 0EA, Wales, UK
Tel: ++44 (01766) 523570 URL: http://www.the-coa.org.uk
**********************************************************************
Dannon Rhudy on fri 23 may 03
Janet said:
> > I get to see the work of many functional potters, but I have never seen
> > them use paperclay, Lari. There has to be a certain "integrity" to a
clay
> > body used for functional work, which most paperclay simply does not
> > possess.........
Much of my work is made at least in part of paper clay. I don't use
a commercial mix, so I can't speak to that issue. I simply add paper
(shredded newspaper, while mixing in a Soldner) until I judge that
the mixture is sufficiently fibrous for my uses.
I am not going to argue with Ron Roy about whether paper clay is
more porous when fired. I am sure that it may well be. However,
I use a porcelain, or perhaps more properly a porcelainous stoneware
body, fired to cone 10. It does not leak, unless it has a hole in it (I
have been known to test a bowl base with a needle to check thickness,
and then forget to smooth it back over and THEN to use a tenmoku
glaze. Hmmmm. Not my brightest move.) I use this body for teapots
if they are textured, for large platters, for very large bowls. I use it
for
oil lamps. I know of no case where the ware has leaked. It seems to
be a very strong body after firing. I use it, in a slightly more groggy
mix,
for garden wares. It holds up well in freeze-
thaw conditions. At least, so far so good. Cushing has an interesting
word or two regarding sculptural bodies for outdoor use - take a look
at his workbook.
Of course, I fire my work to a pretty good state of vitrification. Cone 6
firings, especially for those "cone 6 - 10" commercial clays, are another
story. Testing is everything.
regards
Dannon Rhudy
Janet Kaiser on mon 26 may 03
Sorry, although I was replying to a specific question, I should have
written "functional EVERYDAY DOMESTIC ware" to save any misunderstanding.
And I repeat: not one potter I know uses paperclay for anything which would
fall into that category. Not mugs, cups, teapots or casseroles.
There are naturally many who do use paperclay... On work which requires the
two main advantages of lightness combined with strength. I do not
PERSONALLY see those two attributes being advantageous in a finished tea
cup (for example). Not unless the majority of my clients are more used to
drinking out of styrofoam/polystyrene or some other lightweight material
and generally found my teacups to be "far too heavy" even if eggshell thin.
Maybe then the extra work involved in making paperclay would be worthwhile
and desirable? But only if they withstood the test of time of everyday use
in a "normal" household with a dishwasher, microwave, oven and deep freeze,
as well as standing on wooden surfaces full of liquid for a day or two
without leaving a mark.
Indeed... Thinking about it... Imagine picking up a mug of a known size.
One has already gauged the weight and "know" how heavy it will be whether
full, half full or empty. I get this mental image of picking up a cup which
is suddenly not half the weight expected... I know it is silly, but all I
can see is me throwing the contents all over myself or over my shoulder if
I am lucky! HA! Ha! Why do these ridiculous mental images keep popping into
my head? I don't know, but seriously...
It is all about using the right tools for the job at hand. I do not hold
with the theory that "anything goes as long as it works". Especially not
when there are potential safety issues, but also if finished work is not up
to a recognised or expected standard through the use of the wrong tools.
Knowing the strengths and weaknesses of each material they have at their
disposal, is just one of the skills of the accomplished maker. That skill
is learned over time and there is no substitute however much advice is
sought and given. Not even Clayart can replace a personal learning curve.
That may be stating the obvious, but I thought it time someone raised the
point. Even someone who is apparently not qualified to speak out on
Clayart. Yes, you guys, I do notice the unsubtle "hints" from time to time,
but let's just say you should eat more wheaties too!
Sincerely
Janet Kaiser
**********************************************************************
TRUTH is too precious to tell every fool who asks for it...
****** This post was sent to you today by Janet Kaiser *******
The Chapel of Art / Capel Celfyddyd
8 Marine Crescent, Criccieth LL52 0EA, Wales, UK
Tel: ++44 (01766) 523570 URL: http://www.the-coa.org.uk
**********************************************************************
Ron Roy on tue 27 may 03
Hi Cate,
I think I already explained this - think about water getting in the clay -
through the foot - if the glaze surface is perfect and stays that way. How
long before who knows what starts living and reproducing there - not to
mention what will happen in the microwave. The clay will heat up - handles
will heat up - ask David Hendley what happens then.
It is not right to minimize this situation - potters who make a living from
our craft depend on return sales - it makes sense to make a product that
solves all the problems when ever you can.
RR
>RR says paper clay not good for functional wares because the paper burns out
>and leaves channels..which is true, but isn't that what glazing is for? The
>correct glaze should melt and fill in all those little channels and create an
>impervious surface, just like any other clay body. I think.
>Cate in AZ
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Ron Roy on tue 27 may 03
Hi Linda,
The number I use to determine if clay will hold water is 3% absorption. If
you tolerate more than that water will begin to enter the clay at some
point - how fast depends on the degree of underfiring.
So here are some figures from the lab at Tuckers - same recipe for each
clay with and without paper pulp.
Absorbency = abs
Cone 04 Low White
No paper - averaged over 10 batches - abs = 12.2
With paper - averaged over 4 batches - abs = 17.7
---------------------------------------------------------------------
Cone 6
MCS - a vitrified cone 6 porcelain
No Paper abs is averaged at 0.1%
Paper added - abs averaged - 13 batches since January 6.56 most is 7.6
lowest is 6.0
Mid Smooth Stone - a smooth pale stoneware.
Average abs with no paper - averaged over 11 batches - 2.25
Average with paper 4 batches - 7.02
----------------------------------------------------------------------
Cone 10 oxidation.
Sandstone - light sand coloured stoneware with 5% grog.
No paper - averaged over 4 batches - abs = 0.88
With paper - averaged over 2 batches - abs = 5.6
There is no doubt in my mind that water will get into the clay and through
in the case of the paper clay - even if the clay is overfired (like no
absorption - see the MCS cone 6 porcelain to see why I think that) - but I
am open to the argument that the channels will close up enough eventually
if the clay is fired high enough. If someone wants to provide the data. On
the other hand - overfiring can lead to other problems.
As for paper clay being as strong as the no paper variety - I have no data
but I suspect it will not be as strong but the difference will not be
large.
RR
>Ron,
>I can't answer for other clay bodies...but is increased absorption the same
>as too much absorption? Low fire ware has great absorption, and inherent
>weakness. At least in my experience of broken and chipped ware I have used,
>but it is still used. A stoneware clay that already has low absorption with
>added paper fibers - is it necessarily too porous to use? I am not
>disagreeing but my experience is when it comes to using my own body.
>
>Linda
>Ithaca, NY
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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