If you can't find a pizza stone any unglazed tile should work. There was recently a discussion on this topic on a Facebook RV forum.
Do the tile have to be unglazed? I was all set to buy some tiles for our oven until I read the above. I don't know where to buy unglazed tiles. Lowes sells glazed tile.
I can't dispute Cookie's comments but we've had the tiles in place for several years with no adverse effects. The 6" tiles fit nicely but I noticed we need to clean our oven a bit.
We use our Half-Time/Microwave/Convection oven every day..
We cook our biscuits and pizza and pies etc. on convection setting.
Works every time.... No burnt biscuits or anything.
Nice and brown all over.. 450 deg. for 18 min. for 4 biscuits.... perfect...
We store bread etc. in the conventional oven. Use it rarely.
I purchased unglazed cooking stones from amazon.com and placed in the oven like Ray did. They work great. I don't take them out and so far (fingers crossed) they haven't broken while traveling.
http://www.amazon.com/Kitchen-Suppl...&qid=1386893280&sr=1-1&keywords=cooking+stone
I cooked cinnamon rolls the first morning and the response from the family was "you burned the bottom". Nice to see so many suggestions here to correct that problem!