claclana Posted December 12, 2011 Report Share Posted December 12, 2011 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!! Link to comment Share on other sites More sharing options...
bciskepottery Posted December 13, 2011 Report Share Posted December 13, 2011 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. Link to comment Share on other sites More sharing options...
Benhim Posted December 13, 2011 Report Share Posted December 13, 2011 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 Link to comment Share on other sites More sharing options...
Marcia Selsor Posted December 13, 2011 Report Share Posted December 13, 2011 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 Link to comment Share on other sites More sharing options...
TheSmartCat Posted December 13, 2011 Report Share Posted December 13, 2011 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. Link to comment Share on other sites More sharing options...
claclana Posted December 15, 2011 Author Report Share Posted December 15, 2011 Thank you for the multiple options! I will try them and see which works for me Link to comment Share on other sites More sharing options...
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