Wanda Holmes on sat 27 apr 02
I am at my wit's end. I've recently moved from testing lots of ideas to
making a large batch of tiles for a project. Moving into production mode
has raised all kinds of new issues. One is that I have excessive loss to
warping - a problem that was probably always there, I just wasnt' paying
close attention to it. This is my technique:
1. Roll slab using Northstar slab roller - cut 1/4 of 25 lb pug, roll once
at 1", rotate 90 degrees, roll at 3/4", rotate 90 degrees, roll at 5/8",
then at 1/2" without picking up or moving the slab for the final two rolls.
I roll with heavy canvas on the bottom and slab mat on the top.
2. Gently pull slab up onto sheetrock board. Flip onto second board to free
my canvas. Using a "L" square, a board the width of my desired tile, and a
needle tool, gently mark the tiles on the slab. Place on drying rack. Add
additional boards up to 4 slabs in a stack, top with a final board and cover
loosely with plastic.
3. When clay has set up a bit but is still not yet leatherhard, cut tiles
with a painter's knife by one quick down motion along the previously scored
line. Gently separate with the painter's knife, compress the bottom edges,
and flip onto a dry sheetrock board. Compress the top edges. Return to
drying racks, 4 boards to a stack with a board on top, covered loosely with
plastic. Leave the plastic on for 10 days, fliping the tiles once or twice
during that time to dry boards.
4. Place the tiles on dry sheet rock boards on open air shelves, stacked two
tiles high with no covering board and allow to finish drying.
5. Bisque to 04 with the following program - 90F to 212F, 212F to 1765F,
hold 2 hours, 108F to 1945F. The tiles are placed flat and stacked two high
on each shelf for the bisque firing.
I've now tested 4 different clay bodies repeatedly and the unwarped yields
coming out of the bisque are as low as 25%. Can any of you spot what I'm
doing wrong? All suggestions will be welcomed like a drowning woman
reaching for the life preserver. Thanks, Wanda
Wanda Holmes on sun 28 apr 02
Of the four claybodies that I have been testing, one is heavily grog-ed, and
it warps just like the rest. That seems to me a clue that the problem has
to do with my handling of the slabs, but I haven't been able to pinpoint the
problem. I don't have a problem with the slabs or tiles sticking to the
boards, so I never "peel" them.
I did make an improvement today in getting the slab from the slab roller
table onto a board. I'm hoping this helps. My Northstar has two rollers,
so there is no board, only canvas, under the slab on the slab roller table.
I had been grasping the canvas and gently pulling the slab up onto a board
lying on the table. Today my husband mounted a bracket on the end of my
slab roller table that allows me to rest the sheetrock board flush with the
table and pull the slab from the table onto the board without any change in
plane whatsoever. Of course, the hard part is the weeks of drying to see if
the improvement made a difference.
Wanda
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of William Hendry
Sent: Sunday, April 28, 2002 5:45 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Help - warping tiles
Wanda, two questions:
How much grog is in the bodies you're using?
How soon do you move the tiles before they're leather hard? Do you have to
"peel" them (even a little bit) off the sheetrock when you cut and move
them?
FWIW, I make lots of tiles and never worry about flipping or whether the
boards are wet. I try to disturb the tile as little as possible until they
are LH. I put 'em between Sheet Rock and weight the top board. Then I just
rotate the boards in the stack, taking the bottom board and putting it on
the top every couple of days. You can also flip the stack, changing the
direction of the pressure. (You might have to do this board by board though
;) I might add that I don't do a lot of heavy relief work so this works
consistently for me.
Chris and Nissa on sun 28 apr 02
Wanda,
I use a very similar system. The only thing I do different is when you cut
the tiles before being leather hard I leave a section of the clay around the
outside. This outer clay frame helps the tile inside dry more evenly. The
edges after all dry fastest taking more of the stresses from air contact
etc...-warp. Hope this might help.
Chris
Duluth: 3-4 inches of snow this morning...
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Wanda Holmes
Sent: Saturday, April 27, 2002 10:25 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Help - warping tiles
I am at my wit's end. I've recently moved from testing lots of ideas to
making a large batch of tiles for a project. Moving into production mode
has raised all kinds of new issues. One is that I have excessive loss to
warping - a problem that was probably always there, I just wasnt' paying
close attention to it. This is my technique:
1. Roll slab using Northstar slab roller - cut 1/4 of 25 lb pug, roll once
at 1", rotate 90 degrees, roll at 3/4", rotate 90 degrees, roll at 5/8",
then at 1/2" without picking up or moving the slab for the final two rolls.
I roll with heavy canvas on the bottom and slab mat on the top.
2. Gently pull slab up onto sheetrock board. Flip onto second board to free
my canvas. Using a "L" square, a board the width of my desired tile, and a
needle tool, gently mark the tiles on the slab. Place on drying rack. Add
additional boards up to 4 slabs in a stack, top with a final board and cover
loosely with plastic.
3. When clay has set up a bit but is still not yet leatherhard, cut tiles
with a painter's knife by one quick down motion along the previously scored
line. Gently separate with the painter's knife, compress the bottom edges,
and flip onto a dry sheetrock board. Compress the top edges. Return to
drying racks, 4 boards to a stack with a board on top, covered loosely with
plastic. Leave the plastic on for 10 days, fliping the tiles once or twice
during that time to dry boards.
4. Place the tiles on dry sheet rock boards on open air shelves, stacked two
tiles high with no covering board and allow to finish drying.
5. Bisque to 04 with the following program - 90F to 212F, 212F to 1765F,
hold 2 hours, 108F to 1945F. The tiles are placed flat and stacked two high
on each shelf for the bisque firing.
I've now tested 4 different clay bodies repeatedly and the unwarped yields
coming out of the bisque are as low as 25%. Can any of you spot what I'm
doing wrong? All suggestions will be welcomed like a drowning woman
reaching for the life preserver. Thanks, Wanda
____________________________________________________________________________
__
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You may look at the archives for the list or change your subscription
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William Hendry on sun 28 apr 02
Wanda, two questions:
How much grog is in the bodies you're using?
How soon do you move the tiles before they're leather hard? Do you have to
"peel" them (even a little bit) off the sheetrock when you cut and move
them?
FWIW, I make lots of tiles and never worry about flipping or whether the
boards are wet. I try to disturb the tile as little as possible until they
are LH. I put 'em between Sheet Rock and weight the top board. Then I just
rotate the boards in the stack, taking the bottom board and putting it on
the top every couple of days. You can also flip the stack, changing the
direction of the pressure. (You might have to do this board by board though
;) I might add that I don't do a lot of heavy relief work so this works
consistently for me.
William
----- Original Message -----
From: "Wanda Holmes"
To:
Sent: Saturday, April 27, 2002 11:24 PM
Subject: Help - warping tiles
> I am at my wit's end. I've recently moved from testing lots of ideas to
> making a large batch of tiles for a project. Moving into production mode
> has raised all kinds of new issues. One is that I have excessive loss to
> warping - a problem that was probably always there, I just wasnt' paying
> close attention to it. This is my technique:
>
> 1. Roll slab using Northstar slab roller - cut 1/4 of 25 lb pug, roll once
> at 1", rotate 90 degrees, roll at 3/4", rotate 90 degrees, roll at 5/8",
> then at 1/2" without picking up or moving the slab for the final two
rolls.
> I roll with heavy canvas on the bottom and slab mat on the top.
>
> 2. Gently pull slab up onto sheetrock board. Flip onto second board to
free
> my canvas. Using a "L" square, a board the width of my desired tile, and
a
> needle tool, gently mark the tiles on the slab. Place on drying rack.
Add
> additional boards up to 4 slabs in a stack, top with a final board and
cover
> loosely with plastic.
>
> 3. When clay has set up a bit but is still not yet leatherhard, cut tiles
> with a painter's knife by one quick down motion along the previously
scored
> line. Gently separate with the painter's knife, compress the bottom
edges,
> and flip onto a dry sheetrock board. Compress the top edges. Return to
> drying racks, 4 boards to a stack with a board on top, covered loosely
with
> plastic. Leave the plastic on for 10 days, fliping the tiles once or
twice
> during that time to dry boards.
>
> 4. Place the tiles on dry sheet rock boards on open air shelves, stacked
two
> tiles high with no covering board and allow to finish drying.
>
> 5. Bisque to 04 with the following program - 90F to 212F, 212F to 1765F,
> hold 2 hours, 108F to 1945F. The tiles are placed flat and stacked two
high
> on each shelf for the bisque firing.
>
> I've now tested 4 different clay bodies repeatedly and the unwarped yields
> coming out of the bisque are as low as 25%. Can any of you spot what I'm
> doing wrong? All suggestions will be welcomed like a drowning woman
> reaching for the life preserver. Thanks, Wanda
>
>
____________________________________________________________________________
__
> 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.
Joseph Dallas on mon 29 apr 02
Hi Wanda,
What size tiles are you making with these 1/2 inch slabs?
I found that tiles larger than 6x6 would warp no matter
what I did. When making tiles larger than 6x6 I use at
least a 3/4 inch slab. I also use a clay with 33% grog.
I also found that if I bisque fire with the tiles face-down
if it curls up, then when I glaze fire they flatten back
out. This is with large tiles, 12x12.
Hope this helps.
Later,
Joe Dallas
Dallas Pottery & Architectural Ceramics
jedallas@att.net
http://home.att.net/~jedallas
Wanda Holmes wrote:
>
> I am at my wit's end.
claybair on mon 29 apr 02
Wanda,
In reading your posting today I was wondering if and how you remove the
canvas from the slab when you pull it onto the sheet rock?
If you are inundated with emails you do not have to respond but whenever you
do find what caused the warping do let me know.
Gayle Bair
Bainbridge Island, WA
http://claybair.com
Wanda Holmes on mon 29 apr 02
Gayle, I pull the canvas with the slab on it onto a sheetrock board
supported by a bracket my huband added to the end of my slab roller table.
The bracket allows me to position the board at the same height as the table
and pull the slab onto it without any vertical movement. Once the canvas
and slab are on the board, I put another sheetrock board on top and flip the
whole sandwich over. Then I peel the canvas off the top.
Wanda
Gayle wrote:
.....I was wondering if and how you remove the
canvas from the slab when you pull it onto the sheet rock?
Ron Collins on mon 29 apr 02
>Put another piece of sheet rock on top and flip it over.....
In reading your posting today I was wondering if and how you remove the
> canvas from the slab when you pull it onto the sheet rock?
>
____________________________________________________________________________
__
> 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.
>
Michele Williams on mon 29 apr 02
I would like to know what prevents warping tiles, also. I'm not in
production, but I don't have time to waste, either. I do bas relief,
fragile leaves, ferns, etc., and I can't exactly slam the things down onto
the carved side.
Michele Williams
----- Original Message -----
From: "claybair"
To:
Sent: Monday, April 29, 2002 12:03 PM
Subject: Re: Help - warping tiles
> Wanda,
>
> In reading your posting today I was wondering if and how you remove the
> canvas from the slab when you pull it onto the sheet rock?
> If you are inundated with emails you do not have to respond but whenever
you
> do find what caused the warping do let me know.
>
> Gayle Bair
> Bainbridge Island, WA
> http://claybair.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.
>
William Hendry on tue 30 apr 02
Steve,
Do you think that only cutting the slab 3/4 of the way through help prevent
warping or is that more about not distorting the corners?
William
----- Original Message -----
From: "Steve Mills"
To:
Sent: Tuesday, April 30, 2002 5:10 PM
Subject: Re: Help - warping tiles
> We supply several Tile makers with clay, usually with a fairly high
> sand/grog content (20 percent). This method is a combination of the
> system used by 2 makers and has a very high degree of success.
> On your rolled out slab of clay, mark out the tiles and cut them THREE
> QUARTERS OF THE WAY THROUGH, no more, with a pizza wheel cutter. leave
> 'till on the dry side of leather hard, then break apart like pieces of
> chocolate. Trim the edges with a small Surform plane, and dry. All the
> drying is done on plaster-board which is raised up on laths. that way
> the top and bottom of the clay dry at the same rate. This method has
> almost eliminated warping and the tendency of the tile corners to
> distort due to the passage of the knife.
>
> Steve
> Bath
> UK
>
>
> In message , Wanda Holmes writes
> >I am at my wit's end. I've recently moved from testing lots of ideas to
> >making a large batch of tiles for a project. Moving into production mode
> >has raised all kinds of new issues. One is that I have excessive loss to
> >warping - a problem that was probably always there, I just wasnt' paying
> >close attention to it. This is my technique:
> >
> >1. Roll slab using Northstar slab roller - cut 1/4 of 25 lb pug, roll
once
> >at 1", rotate 90 degrees, roll at 3/4", rotate 90 degrees, roll at 5/8",
> >then at 1/2" without picking up or moving the slab for the final two
rolls.
> >I roll with heavy canvas on the bottom and slab mat on the top.
> >
> >2. Gently pull slab up onto sheetrock board. Flip onto second board to
free
> >my canvas. Using a "L" square, a board the width of my desired tile, and
a
> >needle tool, gently mark the tiles on the slab. Place on drying rack.
Add
> >additional boards up to 4 slabs in a stack, top with a final board and
cover
> >loosely with plastic.
> >
> >3. When clay has set up a bit but is still not yet leatherhard, cut tiles
> >with a painter's knife by one quick down motion along the previously
scored
> >line. Gently separate with the painter's knife, compress the bottom
edges,
> >and flip onto a dry sheetrock board. Compress the top edges. Return to
> >drying racks, 4 boards to a stack with a board on top, covered loosely
with
> >plastic. Leave the plastic on for 10 days, fliping the tiles once or
twice
> >during that time to dry boards.
> >
> >4. Place the tiles on dry sheet rock boards on open air shelves, stacked
two
> >tiles high with no covering board and allow to finish drying.
> >
> >5. Bisque to 04 with the following program - 90F to 212F, 212F to 1765F,
> >hold 2 hours, 108F to 1945F. The tiles are placed flat and stacked two
high
> >on each shelf for the bisque firing.
> >
> >I've now tested 4 different clay bodies repeatedly and the unwarped
yields
> >coming out of the bisque are as low as 25%. Can any of you spot what I'm
> >doing wrong? All suggestions will be welcomed like a drowning woman
> >reaching for the life preserver. Thanks, Wanda
>
> --
> Steve Mills
> Bath
> UK
>
>
____________________________________________________________________________
__
> 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.
Steve Mills on thu 2 may 02
No I don't, there is no need to, plasterboard (it goes up on walls in
the UK and is plastered over, you may well call it something different
in other parts of the world) is very thin (1/2 inch at the most), and
raised up on laths sucks out moisture and sheds it VERY quickly.
Steve
Bath
UK
In message , Jennifer Buckner writes
>At 05:10 PM 4/30/02, Steve in Bath,UK wrote:
>>Trim the edges with a small Surform plane, and dry. All the
>>drying is done on plaster-board which is raised up on laths. that way
>>the top and bottom of the clay dry at the same rate.
>
>Steve, do you also put a piece of plaster-board on top of the tiles as
>they're drying too?
>
>Jennifer
>
>
>
>
>Jennifer G. Buckner jenniverre@pgtv.net
--
Steve Mills
Bath
UK
Steve Mills on thu 2 may 02
More about warping, the pizza cutter helps with distortion.
Steve
Bath
UK
In message , William Hendry writes
>Steve,
>
>Do you think that only cutting the slab 3/4 of the way through help preve=
>nt
>warping or is that more about not distorting the corners?
>
>William
>----- Original Message -----
>From: "Steve Mills"
>To:
>Sent: Tuesday, April 30, 2002 5:10 PM
>Subject: Re: Help - warping tiles
>
>
>> We supply several Tile makers with clay, usually with a fairly high
>> sand/grog content (20 percent). This method is a combination of the
>> system used by 2 makers and has a very high degree of success.
>> On your rolled out slab of clay, mark out the tiles and cut them THREE
>> QUARTERS OF THE WAY THROUGH, no more, with a pizza wheel cutter. leave
>> 'till on the dry side of leather hard, then break apart like pieces of
>> chocolate. Trim the edges with a small Surform plane, and dry. All the
>> drying is done on plaster-board which is raised up on laths. that way
>> the top and bottom of the clay dry at the same rate. This method has
>> almost eliminated warping and the tendency of the tile corners to
>> distort due to the passage of the knife.
>>
>> Steve
>> Bath
>> UK
>>
>>
>> In message , Wanda Holmes writes
>> >I am at my wit's end. I've recently moved from testing lots of ideas =
>to
>> >making a large batch of tiles for a project. Moving into production m=
>ode
>> >has raised all kinds of new issues. One is that I have excessive loss=
> to
>> >warping - a problem that was probably always there, I just wasnt' payi=
>ng
>> >close attention to it. This is my technique:
>> >
>> >1. Roll slab using Northstar slab roller - cut 1/4 of 25 lb pug, roll
>once
>> >at 1", rotate 90 degrees, roll at 3/4", rotate 90 degrees, roll at 5/8=
>",
>> >then at 1/2" without picking up or moving the slab for the final two
>rolls.
>> >I roll with heavy canvas on the bottom and slab mat on the top.
>> >
>> >2. Gently pull slab up onto sheetrock board. Flip onto second board t=
>o
>free
>> >my canvas. Using a "L" square, a board the width of my desired tile, =
>and
> a
>> >needle tool, gently mark the tiles on the slab. Place on drying rack.
>Add
>> >additional boards up to 4 slabs in a stack, top with a final board and
>cover
>> >loosely with plastic.
>> >
>> >3. When clay has set up a bit but is still not yet leatherhard, cut ti=
>les
>> >with a painter's knife by one quick down motion along the previously
>scored
>> >line. Gently separate with the painter's knife, compress the bottom
>edges,
>> >and flip onto a dry sheetrock board. Compress the top edges. Return =
>to
>> >drying racks, 4 boards to a stack with a board on top, covered loosely
>with
>> >plastic. Leave the plastic on for 10 days, fliping the tiles once or
>twice
>> >during that time to dry boards.
>> >
>> >4. Place the tiles on dry sheet rock boards on open air shelves, stack=
>ed
>two
>> >tiles high with no covering board and allow to finish drying.
>> >
>> >5. Bisque to 04 with the following program - 90F to 212F, 212F to 1765=
>F,
>> >hold 2 hours, 108F to 1945F. The tiles are placed flat and stacked tw=
>o
>high
>> >on each shelf for the bisque firing.
>> >
>> >I've now tested 4 different clay bodies repeatedly and the unwarped
>yields
>> >coming out of the bisque are as low as 25%. Can any of you spot what =
>I'm
>> >doing wrong? All suggestions will be welcomed like a drowning woman
>> >reaching for the life preserver. Thanks, Wanda
>>
>> --
>> Steve Mills
>> Bath
>> UK
>>
>>
>_________________________________________________________________________=
>___
>__
>> 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.
--
Steve Mills
Bath
UK
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