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throwing polar porcelain cone 5-8

updated mon 4 oct 04

 

Laurie Kneppel on thu 30 sep 04


On Sep 30, 2004, at 8:56 AM, Llewellyn Kouba wrote:

> Has anyone worked with the Cone 5-8 Polar porcelain. Last week I threw
> some on the potters wheel and it is great stuff. Today I tried my hand
> at
> some 3-4.5 lb plates. Every time I try and cut them off the bat they
> slice
> on up through the plate.

Hi Llewellyn,
Sounds like a nice clay. I don't throw a huge number of plates, but
when I do I have found the very best thing that works for me is to
throw them on plaster bats so that they self-release as they firm up.
For me, cutting with a wire off a plastic bat or other non porous
surface I cannot get a good clean cut on really wide things. (probably
something that would improve with practice! ) But the plaster bat
solution works so well it's what I use. As soon as they dry enough to
easily remove them from the plaster bat they are usually about ready
for their footrings then they are set on a shelf lined with a piece of
hardibacker (cement tile underlayment) board. I have minimal if any
warping during the drying this way, too.

Good luck with the plates!

Laurie
Sacramento, CA
http://rockyraku.com
Potters Council, charter member
Sacramento Potters Group, member (www.sacramentopottersgroup.com)

Louis Katz on thu 30 sep 04


If you are working with plaster or some other absorbent bat you may
find that the clay is stiffening even as you throw.
If its plaster you may want to just wait until the pot pops off.
Otherwise use a thin stiff wire like a guitar string or steel
harpsichord wire.
Louis
On Sep 30, 2004, at 10:56 AM, Llewellyn Kouba wrote:
> Every time I try and cut them off the bat they slice
> on up through the plate.

Llewellyn Kouba on thu 30 sep 04


Has anyone worked with the Cone 5-8 Polar porcelain. Last week I threw
some on the potters wheel and it is great stuff. Today I tried my hand at
some 3-4.5 lb plates. Every time I try and cut them off the bat they slice
on up through the plate. What gives? I know I had some trouble with this
before on higher cone clay and the problem I discovered was if you didn't
cut them off the bat right away and tried it latter in the game the string
would just move on up through the clay piece and ruin it. So I figured it
was the same for Polar and did this right away- stringed them off at the
wheel when satisfied that the work looked good. Same thing happens. So
does this one have to stand longer or work the opposite? May be that you
can't work too large with it? but I did manage to get a few larger plates
off last week so am trying to figure this one out. I make a clean sweep
edge with my wood tools around the edge before I enter and yet it goes in a
ways and on up out throught the bottom. Most discouraging after all the
work. Any tips?

Llewellyn Kouba
Abbey Pottery

Rod Wuetherick on thu 30 sep 04


Llewellyn,

First off Llewellyn it is odd you say you have this problem with plates and
not everything else you may cut off the wheel. It surely is one of two
things, the first being the more likely.

First you need to remember that when you cut things off the bat your cutting
wire does tend rise up in the center slightly. You need to keep a very firm
grip on the wire and use your thumbs to press and hold the wire to the
bat/wheel head. With the wheel head revolving slowly pull from the back to
the front keeping that wire taut. Learn to leave a little bit of clay to
compensate for this "slight rise" which should be 2-5 mm at most. Otherwise
you probably are not holding the wire as per above.

Secondly with plates you shouldn't be having this problem as plates
generally need to be thrown quite thick in order to facilitate a foot ring.
With porcelain you will defiantly need an inner and outer foot ring. With
stoneware you can often get away with one but I use two here as well as I
find you need to leave the plate thicker than you would like so that it
doesn't warp and fuse to your shelf.

I think if you do the above you will have your irritating problem licked...

Cheers,
Rod


ways and on up out throught the bottom. Most discouraging after all the
work. Any tips?

Llewellyn Kouba

John Bandurchin on fri 1 oct 04


Hi all
If the wire rises up as you are cutting through the clay at the bottom of a
platter, I suggest that the bat has absorbed some of the water from the
clay, and the clay touching the bat is drier and harder than the clay a
sixteenth or an eighth of an inch further away. The wire will take the path
offering the least resistance, thus giving you a concave shape to the bottom
of the platter. This assumes that you are using a bat that is somewhat
absorbent.
Does this make sense???
John Bandurchin

----- Original Message -----
From: "Llewellyn Kouba"
To:
Sent: Friday, October 01, 2004 9:24 AM
Subject: Re: Throwing Polar Porcelain cone 5-8


> Laurie,
>
> Did you make your own plaster bats or buy them? Sounds like a good idea
> to me. Generally I don't have trouble and yesterday after I selected a
very
> think fish line cut off string that seemed to help and then passed through
> the bat slower and making sure it was cutting rather than dragging through
> too quick. I had some better results. Might have been just a bad throwing
> day? anyway your plaster bat intrigues me. I think we had some at school
> but they were fitting only on the kickwheel. They would also probably take
> up more room too then my wood laminate counter top type.
>
> Llewellyn
>
>
> At 12:57 PM 9/30/2004 -0700, you wrote:
> >On Sep 30, 2004, at 8:56 AM, Llewellyn Kouba wrote:
> >
> >>Has anyone worked with the Cone 5-8 Polar porcelain. Last week I threw
> >>some on the potters wheel and it is great stuff. Today I tried my hand
> >>at
> >>some 3-4.5 lb plates. Every time I try and cut them off the bat they
> >>slice
> >>on up through the plate.
> >
> >Hi Llewellyn,
> >Sounds like a nice clay. I don't throw a huge number of plates, but
> >when I do I have found the very best thing that works for me is to
> >throw them on plaster bats so that they self-release as they firm up.
> >For me, cutting with a wire off a plastic bat or other non porous
> >surface I cannot get a good clean cut on really wide things. (probably
> >something that would improve with practice! ) But the plaster bat
> >solution works so well it's what I use. As soon as they dry enough to
> >easily remove them from the plaster bat they are usually about ready
> >for their footrings then they are set on a shelf lined with a piece of
> >hardibacker (cement tile underlayment) board. I have minimal if any
> >warping during the drying this way, too.
> >
> >Good luck with the plates!
> >
> >Laurie
> >Sacramento, CA
> >http://rockyraku.com
> >Potters Council, charter member
> >Sacramento Potters Group, member (www.sacramentopottersgroup.com)
> >
>
>___________________________________________________________________________
___
> >Send postings to clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list or change your subscription
> >settings from http://www.ceramics.org/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
> >melpots@pclink.com.
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.

Llewellyn Kouba on fri 1 oct 04


Laurie,

Did you make your own plaster bats or buy them? Sounds like a good idea
to me. Generally I don't have trouble and yesterday after I selected a very
think fish line cut off string that seemed to help and then passed through
the bat slower and making sure it was cutting rather than dragging through
too quick. I had some better results. Might have been just a bad throwing
day? anyway your plaster bat intrigues me. I think we had some at school
but they were fitting only on the kickwheel. They would also probably take
up more room too then my wood laminate counter top type.

Llewellyn


At 12:57 PM 9/30/2004 -0700, you wrote:
>On Sep 30, 2004, at 8:56 AM, Llewellyn Kouba wrote:
>
>>Has anyone worked with the Cone 5-8 Polar porcelain. Last week I threw
>>some on the potters wheel and it is great stuff. Today I tried my hand
>>at
>>some 3-4.5 lb plates. Every time I try and cut them off the bat they
>>slice
>>on up through the plate.
>
>Hi Llewellyn,
>Sounds like a nice clay. I don't throw a huge number of plates, but
>when I do I have found the very best thing that works for me is to
>throw them on plaster bats so that they self-release as they firm up.
>For me, cutting with a wire off a plastic bat or other non porous
>surface I cannot get a good clean cut on really wide things. (probably
>something that would improve with practice! ) But the plaster bat
>solution works so well it's what I use. As soon as they dry enough to
>easily remove them from the plaster bat they are usually about ready
>for their footrings then they are set on a shelf lined with a piece of
>hardibacker (cement tile underlayment) board. I have minimal if any
>warping during the drying this way, too.
>
>Good luck with the plates!
>
>Laurie
>Sacramento, CA
>http://rockyraku.com
>Potters Council, charter member
>Sacramento Potters Group, member (www.sacramentopottersgroup.com)
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.

Laurie Kneppel on sat 2 oct 04


On Oct 1, 2004, at 6:24 AM, Llewellyn Kouba wrote:

> Laurie,
>
> Did you make your own plaster bats or buy them? Sounds like a good
> idea
> to me.

Hi Llewellyn,

I have both. I've got bats made by pouring plaster in pie tins as well
as some plastic "saucers" from Home Depot that are normally used
underneath flowerpots. The plastic ones are better for re-use because
they keep their shape. The trick is to pour your plaster on a level
surface. I have to admit my favorite bats were some that bought
readymade many years ago. They are perfectly level 14" bats and I love
them for throwing plates.
In my opinion plaster bats make plate throwing so much easier than
trying to cut them off a plastic, masonite or other type bat that I
have used.

Good luck with your plates and platters!

Laurie
Sacramento, CA
http://rockyraku.com
Potters Council, charter member
Sacramento Potters Group, member

John Rodgers on sat 2 oct 04


Llewellyn,

I had the same problem. I started using plaster batts for all my
throwing.I do not cut them free with a wire. They areself releasing for
all my forms.........plates, platters, pots. Problems solved.

Regards,

John Rodgers
Chelsea, AL



Llewellyn Kouba wrote:

> Has anyone worked with the Cone 5-8 Polar porcelain. Last week I threw
> some on the potters wheel and it is great stuff. Today I tried my hand at
> some 3-4.5 lb plates. Every time I try and cut them off the bat they
> slice
> on up through the plate. What gives? I know I had some trouble with this
> before on higher cone clay and the problem I discovered was if you didn't
> cut them off the bat right away and tried it latter in the game the
> string
> would just move on up through the clay piece and ruin it. So I figured it
> was the same for Polar and did this right away- stringed them off at the
> wheel when satisfied that the work looked good. Same thing happens. So
> does this one have to stand longer or work the opposite? May be that you
> can't work too large with it? but I did manage to get a few larger plates
> off last week so am trying to figure this one out. I make a clean sweep
> edge with my wood tools around the edge before I enter and yet it goes
> in a
> ways and on up out throught the bottom. Most discouraging after all the
> work. Any tips?
>
> Llewellyn Kouba
> Abbey Pottery
>
> ______________________________________________________________________________
>
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>