I have a mig, at low wire speeds at any power on my 150amp and 105amp it just spits and spatters. Not a constant arc. I need to go aboth 6-7 on .9mm wire on any thickness steel
Why are you welding with a low wire speed?
Running with the wire speed too low for the welding volts will mean the wire will simply ball up on the end then drop into the weld pool causing loads of spatter.
To set the wire speed, start welding with the speed control knob about half way then slowly turn it up until you feel the torch just start to be pushed away from the workpiece then back the speed control off until it stops pushing. That's the optimal feed speed for welding on the flat.