Does it only work on Alien weapons? How many do you need? I seem to have trouble getting it to work.

Epoxy works on all weapons. Just equip the weapon you want to repair with it, find Alien Epoxy in the Aid menu in your Pip Boy and use it, and the weapon will be repaired by an amount dependent on your Repair skill. Depending on your Repair skill and the starting condition of the weapon, it may take several tubes to repair it to 100%. You may also want to only use it on weapons that are otherwise hard or impossible to repair (like the Gauss Rifle), because you can only get small amounts of new epoxy after completing Mothership Zeta.

Yep, use them sparingly. They don't work on armor

thx guys