shrinking pot in kiln

[claclana]

Hi!

I want to put a big bell like piece to cook in the kiln and was wandering if putting sand (same as silica?) will allow the piece to move as it shrinks (so don't deform it).

Isn't sand glass? doesn't have a lower melting temperature than clay?

if sand don't work, do you have a suggestion?

Thanks!!

[bciskepottery]

You could put a layer of grog down on the kiln shelves instead of sand. The grog can be reclaimed and reused for other items. We keep a large bowl of coarse grog near the studio kilns for large items.

[Benhim]

The right kind of silica sand will work. It's a fairly common practice to put a thin layer of sand under porcelain pots that are highly fluxed. The sand keeps them from sticking to the shelf and breaking off some of the foot ring. It's also a common practice to put quartz gravel on the floor of the ground hog style kilns used in the South.

 

Here's an article on some southern style groundhog kiln practices.

http://people.umass.edu/emartz/martzpots/gallery/50s/58jugtow.htm

[Marcia Selsor]

Grog is good but I use coils about 1/4" thick. I spread them out like sun rays at the base of larger pieces. They allow heat to circulate under the piece.

This has greatly improved survival rate of my architectural pieces.

Marcia

 

 

 

[TheSmartCat]

I build large pieces on a slab the same body and thickness of the piece I am working on. I never had any problems due to the fact that everything shrinks at the same rate.

[claclana]

Thank you for the multiple options! I will try them and see which works for me