Just for fun mix up some epoxy, place it out thin, about 1/16 on wax paper. Now add some MBs and do the same thing. Let it set up for 24 hours. Now pull it off the wax paper and try to snap it in half. See what the strength of epoxy is for yourself. After you know you will be able to decide how and what to use on repairs. Epoxy may not be the best choice. I often use epoxy and a fill to smooth out the outside of a glass fuse but on the inside of the fuse I often use fiberglass and resin. A lot depends on the type of repair. I have a glass fuse on a pattern plane that requires repairs. The epoxy and MBs will just be a fill then sanded smooth, the real work will be on the inside and probably really ugly but strong.