I stumbled upon this forum and hope to read up on many threads. I have actually put together a tutorial on a DIY induction heater. I am hoping that I can get some feedback on it, and if there any areas I can explain more or better. The link is http://www.mindchallenger.com/inductionheater" [Broken]. I've gotten it up to 2kw input, and the inverter is close to 90% efficient getting the power to the coupling transformer. I do not know the efficiency of the resonant tank. Here is a http://www.youtube.com/watch?v=CyG0Ri0dqI4"to my video showing it melting a 1/2" steel nut.