I rolled the clay over the tile and cut it to size using a fettling knife. The clay is vitreous, but it is not fine-particled enough to produce clean edges and corners. The reason for the raised edge on commercial tiles become clear on this first firing: The glaze can go right to the bottom edge without being in danger of coming into contact with the kiln shelf. Of course, because it was not cut using a cookie cutter, the edges and corners are not nearly as straight and perfect as they should be.
Making a high quality ceramic tile