Use GE Silicone to glue the
Use GE Silicone to glue the washer to the back of the glass, and then attach the rod to the washer (glue, or thread the rod and screw it into the washer, or rather, nut). You could also drill a hole through the center and run the rod through the hole, with a nut on each side to keep the glass in place.
Easiest just to glue
Jester’s Baubles Fused Glass Designs