Spin welding works like this: one thing rotates at high speed and, using the heat of friction, gets melted to another thing. Like other kinds of welding, it makes a very strong bond that requires no fasteners or adhesives; unlike them, it’s easy to do without special training using relatively safe, cheap equipment. You can start spin-welding in your garage with nothing more exotic than a drill press, a couple of skate bearings, and a few recyclable plastic bottles.