I have an old spray can cap, a little one, that is metal. I'll put a little dab of petroleum jelly in it and heat it with my hobby torch until it is quite fluid. I bend the wings of the nylon hinge back out of the way and very carfully dunk just the hinge barrel into the grease. This coats the hinging area so epoxy can't get to it. When gluing it in I slightly thin the epoxy and inject it into the slots cut by a hinge slotter with a syringe and needle...all the way to the bottom of the slot...just a little squirt. Once the hinge is in place I wipe up any excess epoxy with a soft cloth soaked in denatured alcohol. Let the epoxy set and there you go