Mig Welder
EDIT ........I took a look at your regulator photo and it appears to say L/m down in left corner --- That would BE flow as opposed to pressure
Read the manual and make certain the welder polarity is correct at the gun. It may be opposite from flux core. You can buy cheap flow meters, you hold it with the gun pointing up, and the flowmeter on top of the gun. With the wire disabled, it will show you the flow, around 15-20 cfm I've been told.
This is TIG shown here, same deal
On a side note, I don't normally do the delicate work you are attempting, mine is mostly mild steel "backyard fab." If you might do a lot of that I just use pure CO2, it's a LOT cheaper and lasts "forever." CO2 is liquid in the container so there's much more of it so to speak.