Adhesive appears frequently, springs are former weapon parts, carbon composite and factory parts can be obtained from disassembled fire weapons, lenses can be found around the world, and big bones are the reward for killing the most dangerous zombies.
Blueprints can be either found all over the game locations, including the bunker, or obtained in the process of disassembling firearms on the recycler. You can exchange duplicate blueprints in the bunker lobby with the help of the army specialist.