My soldering was running a bit cool, slow to heat up, then slow to heat up splices. I tightened and filed it, not much improvement. So I rectified the 117VAC with a full wave bridge and a 17 microfarad
200VDC cap on it's output to get 154 VDC across the iron.That's 30% greater Voltage and Current, Watts increases by Current X Voltage (1.3^2) or more than 70!. So now it runs good and hot. Ken