hi my name is zach i'm looking for a little help. i got a miller econo twin hf from a buddy for free and the only thing it is missing is the HF switch. I'm looking for somebody that can point me in a direction to purchace the switch or the instuctions to build one. The socket for the HF switch is a three wire and im told the switch is a on/off used for aluminum welding. my serial number on the welder is hf866259 if that helps. i will post pics of it also if i can figure out how. thanks everybody, Zach