Soldering to Chassis

[Electronic M]

Third that.

You need at least a 75W Iron to solder a chassis ground properly like the original work. I've got an older weller (must have been made in the last 30 years since it's orange), and a couple of 150W antique irons that eat chassis ground work for breakfast...They even make new grounds like it is nothing.

Something like a 45W or under iron is close to or below the thermal power rating of the chassis heatsink (and a chassis can be used as a heatsink).