Originally Posted by
unterhausen
There is definitely induction brazing being done every day. I am not sure anyone is brazing enough frames to make it worthwhile to use in bike construction. Seems like it would have to be a giant induction heater to even work on a bike frame, but possibly I'm suffering from a lack of imagination. Multi-head torches like were used in the Merckx factory seem to make more sense.
Trek developed an induction heating system for brazing frames in the mid-80s. It required specially shaped copper blocks to fit around the joints; each joint and frame size needed its own set of blocks to ensure even heating. Automated wire-feed machines fed a pre-determined length of brass wire into the joint after it was heated for a pre-determined time. Shorelines were touched up by hand while the joint was still hot. The system was only used for a couple/few years, as it was developed just as non-steel frames started to become fashionable, and was scrapped when the market became almost exclusively aluminum and carbon fiber.