Years ago we were able to build up the bridge on a zyl frame with lozenge shaped pieces of zyl, about the size of a then-normal zyl pad on a keyhole bridge. We used to call it "zyl build-up", although I don't remember whether that was its proper name. I need some of that stuff to build up the bridge on a pair of oversized sunglasses. Does anyone know where I can get it, or have any left? Hilco used to make it, but it's out of their catalog.