Mullite/cordierite kiln shelf

[breadman_nz]

Continuing my quest for a nice, thick, heat-shock-resistant pizza stone, I have come across a kiln supply shop which has stones which are apparently 45% mullite/45% cordierite/10% silicaceous glass - so-called "Remcor", I believe. Pretty cheap price too, compared to other NZ options:

http://www.furnace-eng.co.nz/Shelfs.htm

Down the bottom of the above page, is a jpg, which I assume represents the composition of the kiln shelves in question. Thermal conductivity for the shelf is listed as 1-1.5Wm/K, which seems quite low. A quick google search suggests these are good kiln shelves, but no info on their toxicity or use as pizza stones.

I suspect it's a very similar shelf if not exactly the same product, as the sillimanite shelf I've previously bought (the nzpotterysupplies website suggests they are from "acme marls", as does the above website. "Remcor" looks to be an "acme marls" formulation. I'll be damned if I can find any info an "acme marls" company through a quick search. It seems kiln shelf manufacturers and retailers are - to use a pun - in the stone age when it comes to detailed info!

For you rock hounds / industrial ceramic experts out there - how do you reckon such a composition (at 3/4" thick) would perform?

[scott123]

Breadman, I think you've got a winner there. It's really tricky- you need a stone that's conductive, but not too conductive and not too thick or not too thin. At 1-1.5Wm/K, it might be a tiny bit on the weak side, but, as I said earlier, it's better to have to mod the oven a bit higher and gain some more top browning than to have a stone with too much conductivity and/or mass and have to go with a lower temp.

With that conductivity, you might need as high as 650 to get the browning you're looking for on the hearth, but I think that's still a comfortable mod, and, with your sensor, not that difficult to achieve.

I say go for it.