Near the end of the One Man's Treasure quest that takes you through Trashlantis, the Clapstructor will fuse into the weld at the girder, but will still be alive. Once no one else is talking and you have been tasked with returning to the Mayor, don't leave the area. Instead go to where the Clapstructor is now and press X to talk to it, unlocking the achievement.
Note: It isn't missable and you'd only have to return to where you leave the Clapstructor to get it later, but it's much simpler to get it right then without any later revisiting.