Pulse Mig, arc colour

[Hitch]

Did some pulse Mig on aluminium the other day. Two diferent machines, one a Selco, the other an Hitachi.

Both on same wire and gas, both doing same joint on same material, voltage is approx the same.
Tried both machines, the selco had a very green arc, but the Hitachi had quite a whiteish blue arc.

What makes the difference in the colour of the arc?

 

[Paul.]

I've noticed that with my SAF Octipuls, in normal mig mode the arc is a normal blue, but in pulse mode the arc is much richer, even to the point of having to turn the headshield up a notch, I really never wondered why, just accepted it one of the effects of synergic welding.

 

[Hitch]

Yes, my lid is set to the darkest available, even just on steel pulse.
I guess the colours comes down to the electronics that controls it?

 

[dannyweld]

the pulse peaks at a very high amperage, could be 350 amps when welding at 22 to 23 volts, maybe thats why its brighter. i,m always on the look out for info on mig pulse, wire speeds, pulse settings etc.