I don't know how the cold irons of late work. I used to use a cordless Wahl that heated in seconds but was hot for a while after. Good little iron. Batteries take a crap after about two years. The other instant heat iron I have is a carbon-finger resistance unit that will tear heck out of any semidelicate component, pickups, diodes, pots, etc. We use it just to make LARGE connections in a hurry, like #10 wires to the back of a fuseholder. It puts out about 120 amps AC @.75 volts and will kill any small wattage thing in its way. Cools instantly, though. Well, IT never gets hot: the part clamped between the fingers does.