Scum. We havn't figured that part out yet. Sometimes he'll get scum and he can't figure out why, like theres no pattern. What causes it?
is he getting it from using a paticular color? Cobalt blue (turbo) is natoriuos for "scumming" up really bad. Use a colder (higher oxy) flame. Also remember to wipe off kiln dust before you put a piece back into the flame. also over fumeing in certian patterns can scum the glass.. Post a pic and I will see what I can tell you about it
