I’m always interested in new ways to solder. [SPman] sent in this diy pulse soldering iron. It heats up in 5 seconds on demand, then cools in about 15. The writeup is a bit terse (since it’s translated from Russian), but it would definitely be handy for larger wiring jobs. The transformer is hand wound, and an oscillation driver forms a sort of crude frequency modulation to run the MOSFETS that drive the heating elements. I’d keep it away from delicate electronics unless you’re confidant of the temperature stability. It was designed for 220V, so you’d need to modify the transformer a bit to get similar performance on a 110V circuit.