Gaynor Reeve on fri 17 mar 00
What went wrong.......
I slab rolled my 20" x 3/8" white grogged earthenware clay and attached 4
feet whilst still on a hump mould.This was to make either a very shallow
platter or a wall plate.
As it dried the rim warped slightly.
Using supports under the rim for extra support, I fired to 1100c.
Still warping, but acceptable at this stage, I went ahead and decorated with
coloured slips.
I refired to 1020c and this time about 1/3 had completely broken off. But, I
did forget to support the rim.
I have tried using paper clay about 50 clay 50 pulp. But after firing,
the platter fell apart. I think I must have rolled the slab too thin.
As I want to try again, I would be grateful for any advice on firing large
flat wall pictures.
Thank you for any replies,
Gaynor
GAYNOR REEVE Ceramic Artist
Kent, England
email: gaynor.reeve@virgin.net
WWW: http://myspace.virgin.net/g.reeve/index.html
Cantello Studios on sat 18 mar 00
1. Roll the slab at a half inch thick.
2. After rolling lift the slab using the bottom canvas as a support with one
hand flat on the edge of the plate and the other flat on the back side of
the canvas press your hands flat together with clay and canvas. Lift and
slide the plate and canvas off the table and allow to hang down while moving
to your hump mold, now start by letting the bottom end of the plate meet the
front edge of the mold then allow the rest of the plate down slowly crossing
the mold tell it is across and down on the mold. Check to see that its line
up edge to edge or as you like before you remove the canvas back. When
removing the canvas do it slowly checking to make sure that you don't lift
the edge of the plate to much. This is where you can cause the warping clay
has a memory and as it dries it will try to get back to that last place were
it was stretched so do this part slowly!
3. after the canvas is off you should take a wet sponge and smooth the plate
down pushing fairly hard. This will help the clay stay down so pay close
attention to the back edge of the rim.
4. You should let the plate sit over night covered before you put the feet
on this way the under side of the plate gets a chance to set up before you
put more pressure on it.
5. Make the feet any way you like but try to keep the clay as dry as you
can. After the feet are on place a small piece of new print on top of the
feet then take a bat and sit on top of feet. Using a level and with the mold
on a level surface check your feet for level making sure that you don't push
the bat down to much check to make sure you left 3\8 to 1\2" of room between
the news print and the plate.
6. Let set over night again this time with out the plastic cover. You may
like to sign it at this point.
7.After it is almost bone dry you can take it off the mold and set it on a
table to dry. If it is not flat at this stage you will need to square up the
feet.
8. The best way I have found to do this is using a metal window screen on a
flat table top. Taking the plate with booth hands set it on the screen on
the table and start with small passes tell all feet are in contact with the
table. Once there are all touching you can keep grinding tell all four feet
are the same shape on the bottom. Your plate is done and if keep on a flat
shelf out of wind it will dry slow and flat. They must dry slow, trying to
push it will only kill it in the end that's it. Chris:)
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.UKY.EDU]On Behalf
Of Gaynor Reeve
Sent: Friday, March 17, 2000 7:29 AM
To: CLAYART@LSV.UKY.EDU
Subject: 20" warped wall plate
----------------------------Original message----------------------------
What went wrong.......
I slab rolled my 20" x 3/8" white grogged earthenware clay and attached 4
feet whilst still on a hump mould.This was to make either a very shallow
platter or a wall plate.
As it dried the rim warped slightly.
Using supports under the rim for extra support, I fired to 1100c.
Still warping, but acceptable at this stage, I went ahead and decorated with
coloured slips.
I refired to 1020c and this time about 1/3 had completely broken off. But, I
did forget to support the rim.
I have tried using paper clay about 50 clay 50 pulp. But after firing,
the platter fell apart. I think I must have rolled the slab too thin.
As I want to try again, I would be grateful for any advice on firing large
flat wall pictures.
Thank you for any replies,
Gaynor
GAYNOR REEVE Ceramic Artist
Kent, England
email: gaynor.reeve@virgin.net
WWW: http://myspace.virgin.net/g.reeve/index.html
Kat Berger on sun 19 mar 00
Several ideas to help you out
1. Make sure clay is very uniform. Wedge extremely well.
2. When rolling the slab, make sure you roll it out evenly in all
directions, otherwise you could compress one side more than another.
3. Dry very slowly and evenly!!! I suggest under plastic for about a
week. Your making a large thin piece and warpage during drying will not
correct itself in this piece.
4. Don't let one side of plate get too close to your elements during
firing bisque. That will exaggerate any warping that has already
occurred.
Hopefully these ideas help you. Remember the larger and thinner a piece
gets the more imperative that everything be done correctly. If you get
a small warp in a mug, it will hold itself together, but in a plate you
also have gravity pulling on the piece and it can't repair itself- via
the cracked piece. I've learned that although it takes much longer to
make these pieces it worth the extra effort.
Kat Berger
Maryland
Marcia Selsor on sun 19 mar 00
It is recommended not to exceed 30% paper pulp when mixing paper clay. I
use about 25% for raku plaques 24" flat. Maybe you could engineer to
feet for better support if going to high temps.
Marcia
Gaynor Reeve wrote:
>
> ----------------------------Original message----------------------------
> What went wrong.......
>
> I slab rolled my 20" x 3/8" white grogged earthenware clay and attached 4
> feet whilst still on a hump mould.This was to make either a very shallow
> platter or a wall plate.
>
> As it dried the rim warped slightly.
>
> Using supports under the rim for extra support, I fired to 1100c.
> Still warping, but acceptable at this stage, I went ahead and decorated with
> coloured slips.
>
> I refired to 1020c and this time about 1/3 had completely broken off. But, I
> did forget to support the rim.
>
> I have tried using paper clay about 50 clay 50 pulp. But after firing,
> the platter fell apart. I think I must have rolled the slab too thin.
>
> As I want to try again, I would be grateful for any advice on firing large
> flat wall pictures.
>
> Thank you for any replies,
>
> Gaynor
>
> GAYNOR REEVE Ceramic Artist
> Kent, England
> email: gaynor.reeve@virgin.net
> WWW: http://myspace.virgin.net/g.reeve/index.html
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/spain99.html
http://www.silverhawk.com/ex99/selsor/welcome.html
Antoinette Badenhorst on tue 21 mar 00
Gaynor, adding talc to your clay, they say, help to make bigger tiles and
platters. Maybe someone know the percentages.Grogged clay of different #
sizes will also help. It sounds to me that you stretched the clay too much.
If you can flatten the clay out first to all directions with the throughing
method, before you put it trough the slabroller, it might help.For real big
stuff the thickness of the clay should not be thinner than 1 cm. When you
carry your clay to a different place to form the platter,roll it lightly into
a sausage to prevent any stretching. Unroll directly on the mold that you
will use. The most important rule will be to dry this piece slowly and let
the air flow around it very even.
I hope this will help you.
Good luck.
Antoinette.
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