It finally happened my borosilicate is chipping. It's now to an unusable point. It looks like alot of people are moving to PEI from this and other threads. I'm hesitate to use a thin layer of PEI because of the chips creating low spots. I was wondering if anyone had tried just replacing the glass with PEI using a 1/4 in sheet? If you haven't, can you tell me if you filled in the glass (epoxy or something else) before putting the PEI down on top of it?