Miller high frequency arc start

The deal breaker on that Arc Start machine for me would be AC. You need to have a wave balance control. Frequency is important for arc stability, but you also need control of how much percentage of the alternating current travels in each direction, to get a good weld on aluminum.

Aluminum would melt at 1200° if the oxide layer didn't need penetrated, but it needs to be cleaned off beyond what you can do with wire brushes, even though that does help some. The arc direction does more cleaning in one direction and more penetrating in the other direction, so depending on the material thickness, series type and how old and/ or dirty a part is, like cast aluminum, you have to be able to control AC wave balance by percentage.

My machine has a knob for that. In addition to wave balance or also referred to as AC balance, some are more sophisticated and have AC and DC wave/ pulse controls to control the initial _ the rise / the high - and the drop time cycles \ of the wave _/-\_/-\_ etc and not just control the frequency of a complete wave ~

It really only helps to have pulse control on DC if you are lazy or want to have a machine do something for you, like a pipe or tubing joint on a lathe, maybe for production work all day, etc, which is way beyond the duty cycle of my welder, but I've never hit it's relay using it for what I do.

pulse on DC can be brought up to higher frequencies around 100hz to cut down on heat, though, which would be nice, but I seem to do just fine on lower settings, with sheet metal, keep the puddle moving and pulse with my foot. Way less distortion than a mig, which I was accustomed to planishing out, anyway, so as far as I'm concerned, it already made my job easier on steel sheet.