|Monthly Tech-Tip |
Example of a buff stoneware clay bloating at cone 10 oxidation (whereas it appears very stable at cone 8). This is a 25x4 recipe employing 200 mesh silica, feldspar, kaolin and ball clay. The cause of this is not always obvious (the body should soften and melt without bloating). This body is fine for the production of ware to cone 8 but obviously, kilns must not be permitted to over-fire.
Bloating occurs when the off-gassing of decomposing particles in a body has not completed by the onset of density and impermeability associated with the vitrification process.