The Power of Friction - Welding With Friction

Paul O'Flaherty

While I have no idea what they’re making, welding with friction looks awesomely cool.

I got two different descriptions of how the weld forms from YouTube, perhaps Geek Is Awesome readers can enlighten me as to which is correct?

With the left side still spinning so fast and the right side not moving at all they wouldn’t actually fuse till the one of the left stopped and it started to cool. So actually it would have to be braked to stop that fast since the “weld” would still be in a soft state


There isn’t a brake. It’s pretty cool, but since the one side is held stationary and the other side is being rotated and welded to it, the weld is actually what stops it so suddenly, as soon as rotation and therefore friction stop, the metal starts cooling instantly, since it is now one piece and the right side is held stationary (so now, the whole weld is cool and the entire piece stationary) instantly stopping the rotating side

Brake or no brake?


  1. joequincy September 18, 2012 at 2:03 pm - Reply

    There’s a brake. In order for the metal to bond with any kind of strength, it has to nearly liquefy first. At that speed, and with the metal so soft, there is no way on earth that the mechanism would have been stopped by friction. In fact, considering how instantly it stopped, I think it’s quite likely that the mechanism utilizes pistons to block the three “spokes” visible in the video, stopping the spin instantly. The actual weld forms after the spinning stops, as the two sides cool down.

    (As backup to my theory… in order to remain spinning against the kind of friction that would turn a metal red-hot, the mechanism would have to be under power the entire time. If the weld suddenly seized, that would HEAVILY damage the motor. The stopping point must be known and controlled so that the motor is not damaged.)

    • Paul O'Flaherty September 18, 2012 at 2:36 pm - Reply

      Thanks Joe. Today I learned a little something new, thanks the you and the internet :)


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