Does epoxy glue work after a ceramics piece has been glaze fired?

I have a ceramics piece that has broken in two. Does the epoxy need to be put on after glaze firing or bisque firing? If after glaze firing, should I leave the two places where it must be put back together uncovered by glaze or should I glaze it was well? Basically, does the epoxy work over a layer of glaze or should the place where it needs to go together not have glaze on it while the rest of the piece does??