Several years ago, Make: contributor Matt Griffin and I were hanging out and he started enthusiastically telling me about a technique for friction welding plastic that he’d just discovered. He had learned about it in a video from the awesome Fran Blanche (she of Frantone guitar pedals fame). I still haven’t tried the technique myself with my Dremel tool, but it couldn’t be easier. You simple chuck some plastic rod into a rotary tool and the friction from the spinning plastic eventually melts it in contact with other plastic parts to form a decent welded bond. Fran’s original video shows you how it works.
And to see it in a real-world situation, here’s a guy repairing a 3D printed Makey the Robot using the technique.
Matt eventually wrote about friction welding in a great piece he did for Make: magazine on various 3D finishing and post-processing techniques. You can read that article here.
[Thanks to Dave Hrynkiw of Solarbotics for reminding me of this ingenious idea.]