I have found heaps of videos and descriptions of home-built inductive heaters. What I haven't found is a good source for actually building one. I understand the idea on a basic level, but the info I find on practical circuits tend to be block diagrams like power supply-->tuned circuit-->work. This is really no help. Where does one start, if he wants to put together a small experimental device, that say heats washers or screws? And what are the practical aspects of the circuit being adjustable for different metals or quantities of metal? How does the circuit scale?