[claclana]

Hi!
I started doing tiles, about 17"x17" with some 3D features that do not allow me to stack them.
I want to put them in the kiln, my problem is that so far for each one they requires it's own shelving
... in my experience they have to have full rest on the horizontal surface or will warp.

Is there any way to stack them with lighter shelves: metal/supported mesh/thinner ceramic shelf/etc, that I don't know about?
I would be happier if could put at least 2-3 tiles between standard shelves...

suggestions!?
THANKS!!!

[Chris Campbell]

Could you tell us what your clay body is and to what cone you are firing?

[claclana]

Hi Chris
I am using just regular white hearthware to by cooked at C-04

[Marcia Selsor]

could you fire them on edge leaning against a brick? I fire my large raku slabs in the bisque on edge. I cushion them with bits of kaowool insulation on the bottom and against the bricks.
Marcia

[claclana]

the tiles I am doing are full of holes, may be is that what makes them more pron to warp?
I had fired a round tile (with holes) in an uneven surface and looks like an 8 from the side!
do you have any opinion on metal shelves (to hold just one tile on top of another tile)?

may be I can make my own ceramic shelves? mmmmmmmmmm

[Marcia Selsor]

Tile setters are ideal because they reduce the mass of heating up in the kiln.
Rather than making your own shelves, look at some innovative ideas of tile setters.
Make three columns and poke holes in each to place pegs to hole the pieces.
Marcia

[bciskepottery]

I'm wondering if plate sitters might be an option.

[claclana]

THANKS Chris Marcia and Bruce!
will search for tile and Plate setters ouch! check this...http://pottery.about...e-and-after.htm


another thing...what would happens if i keep re-firing a piece?
porcelain C10 at multiple C04 for example
or even C04 multiple firing at C04 ,
possible sitters on my own?

[perkolator]

technically, you can re-fire clay dozens of times. typically, you will start hot, then fire cooler for each successive firing. also, the melting temp of each surface will slightly lower the more times you fire it.

as for the warping - make sure you use lots of compressive force when making your slabs. whatever method you use, you definitely want to flip it over and compress from the other side. you mentioned 3D objects being attached to the surface - this can definitely have an effect on warping since they will be forcefully pulling from the one side, only. ideally a large slab should be fully supported from underneath when you fire it, so depending on how you built the slab, how thick it is, how much 3D stuff you added, etc you may or may not be able to stack your slabs with a system like the plate or tile-sitters -- you may end up with bent forms.

in our studio, it's not uncommon for us to have a slab-based project, with most of the slabs being around 24"x36" and 1-2" thick. I ALWAYS fully support these slabs during firing. My method is to suspend the slab on top of gumball-size balls of kiln putty/wadding -- but it's more for cracking issues vs warping (unless the shelves are warped/curved). I've heard of people also firing slabs on beds of grog or silica to achieve the same effect, but have not tried this myself. kiln putty recipe is equal parts silica, kaolin, and grog, mixed to clay consistency.

[Chris Campbell]

On a related note re: warping and slabs .... Watched some chinese potters working with slabs and when they moved their slabs from place to place they used two flat sticks, not their hands. They also cut off the area that was touched during the move. They did this even with rather hard slabs.

[claclana]

Perkolator and Chis:Thanks for all this info!

Perkolator, I am impressed by the huge size of the tiles you worked!

the 3 D is not by addition but by rising from the back of the tiles, less warping temptations , although I carve on this rise surface pretty deep...

I move the tiles by flipping on the board with the rise pattern, make tons of holes and carve the 3D part all this when is very soft (I like the unevenness in the depth of the carved lines) and then slid from wood surface to wood surface (to take off the patterns from underneath), that's it.


I can't wax borders (too many with the holes) neither stack them in a pile with weigh... I think I only can try to not bend and dry slow...


I plan to build a slab roller, hopefully will allow me to go into the surface faster and a more stable fashion, SO many details that require attention! I will check for advises on rollers

doesn't the plate and tile-sitters support the tiles just from the borders and not give a full support?

,

[Marcia Selsor]

I added a photo of a homemade plate setter to the " help with Bisque firing question on cones"
http://ceramicartsda...stion-on-cones/ These are from Spanish potters. I think you'd need thicker hand made pins for your 17 x 17" tiles but
I think they could work in this situation too.
Marcia

[claclana]

mmmmm... nice! thanks Marcia, I may try them with rods to give extended support!?

[Marcia Selsor]

If you mean rods as in a bead rack, that could work but you ma have to saw them down to fit into the posts.. I have only seen clay pins about 3/8" thick.
Marcia

[neilestrick]

Those 3 piece plate setters really won't work well above low fire temps. Too much pyroplasticity. You may be able to do something like that at low fire temps, though. However, your tiles are very big. Personally, I'd just fire them one on a shelf with a little bit of silica sand under them. By the time you have the setter thing all worked out you could be done firing the tiles.

[Marcia Selsor]

I think firing them flat on a shelf even with silica , you would not get even heating. Id recommend using 1/4" coils as spacers between the shelf and the tiles. I use these for large architectural work as well.
Marcia