can anybody explain why some red clays will fire to stoneware temperatures? obviously, the presence of red iron oxide is going to bring the vitrification point down so what is it that allows some red clays to be fired to temperatures used in, say, ash glazing as used by, amongst others, Bernard Leach and Phil Rogers (at least the clay appears to be red). I've also found red clays used in glaze recipes that fire up to cone 9 and possibly beyond.
- posted
20 years ago