warping in the glaze firing ^5

[^5 clay 0]

Hi All

I make flat bottom square platters and I glaze the bottom and fire them on stilt. The platters are flat after the bisque firing but warp in the glaze firing and end up rocking. Does anyone have a similar challenge? Any suggestions? Thanks 

[Chilly 396]

Don't glaze the bottoms, fire them flat on the shelf or on a cookie.

 

[^5 clay 0]

What's a cookie? Also I have to glaze the bottom,  the gift shops I sell them to prefer that. Thanks

 

[Chilly 396]

A cookie is a piece of clay that protects the shelf from glaze runs.

 

[Mark C. 2,194]

The stilt was you call it is your problem.

If you want the bottom glazes add a foot (which is unglazed ) then you can fire the bottom glazed and they will stay flat.The foot does not have glaze . This is the way they should be made really -the glazed bottoms with stilts is a low fire cone 08 thing-not a cone 5-6 thing. Thats why the warping is occurring .

Also a photo would help us diagnosing your issue.

[^5 clay 0]

Thanks Mark, the stilts are the probem I guess, I will experiment with a foot

[yappystudent 125]

^5, you might get some clues from previous forum posts about keeping plates flat. It's a bit of a challenge but there are definitely some things that will help, like making sure to compress the clay hard (I put a board on top and stand on it sometimes) and rolling it out in all directions: think British Flag pattern, which will help keep it from warping. 

[Rae Reich 115]

22 hours ago, yappystudent said:

^5, you might get some clues from previous forum posts about keeping plates flat. It's a bit of a challenge but there are definitely some things that will help, like making sure to compress the clay hard (I put a board on top and stand on it sometimes) and rolling it out in all directions: think British Flag pattern, which will help keep it from warping. 

And never let it bend during construction - clay remembers those bendings during the firing.