[rotorwrench]

One of the major problems with the wire feed welders is the feed system. The wire has to be hard enough to feed or it will break. The "S" or alloy number is only part of the description. The ER70 gives the tensile strength at 70k if you know the system. 70k is pretty hard stuff.

I don't use a wire welder for sheet metal due to the hardness of the filler. I use RG45 with an O/A gas rig to weld sheet metal. The 45k filler wire is much softer and many times I don't have to hammer it at all. I use an aircraft torch to keep the heat down to a minimum. Believe it or not, O/A/gas shields the weld pretty well during the process if done correctly. It's so much easier to weld that I would never use a 60k or 70k filler. I do use the wire feed for welding thicker metals but I also still use the old rod burner too. The wire feed keeps the stuff cleaner with Argon/CO2 mix but the rod burner is less expensive to operate out in the toolies.