I wouldn't use epoxy on brake bridges, if that is what you are asking. However, epoxy is more than adequate for brake bridges. The tensile strength far exceeds the braking forces that part encounters. I wouldn't do it though, unless carbon was involved. Anyway, that is a diversion from the real topic. The original poster inquired about moving cable stops. Brake or derailler cable stops can definitely be done with epoxy like JB Weld. The yield strength is very much within the range of epoxies.