This question is a bit unique, so hang in there with me. I'm an advanced D-I-Y'er doing a bathroom and I have a question about unglazed ceramic bisque tile.
My mother and niece are pottery buffs and we have a free, hand-me-down Skutt brand electric kiln in the basement. The kiln is circular, about 3 feet wide & high. I wired it myself and it is pretty outrageous for a private home. Fully cranked it sucks 40 amps per each leg for a total draw of 80 amps of 120V (maximum temperature is 2,350F). It's quite a sight while running. We have to leave the outside door open for cooling, even in winter.
We are considering obtaining fired but unglazed tile (bisque), glazing them with our own design, then firing them. We want to do our own floor mosaic.
Anyone know where we could buy unglazed tile that could be used on the floor? I found one web site that sold unglazed tile but said don't use them for floor tiles.
I played with pottery a bit in college.
I'm trying to remember....
I know there are different types of clays, and like Mike said, not all are appropriate or strong enough for floor tile.
Then there is the firing temperature (or cone). Different clays are fired at different temps.
Even if you were to find tiles, I'd be afraid a decorative glaze would be too delicate to survive a floor.