I'm starting a new thread on firing glass on clay. This subject has been brought up on this thread and I thought if we are going to discuss this further we could do so here to avoid digressing too far from the OP's original question in the above thread. I'm going to start this thread off with this post from @Chilly : "It terrifies me that you sell stuff that you know splinters. I really don't understand using glass with clay.  To me it's like putting diesel in your petrol-engine