MIG Regulators FAQs
Straight answers to the questions people ask most when choosing and using regulators for MIG shielding gas.
What does a MIG gas regulator do?
A regulator reduces the high pressure in the gas cylinder to a low, steady working pressure, and lets you set the flow that goes to the welding torch. Without it the gas would come out far too fast and the pressure would change as the cylinder emptied.
A steady, correctly set flow gives a good shielding gas cover over the weld pool, which protects the weld from the air. Too little gas lets air in and gives porous welds, while too much wastes gas and can cause turbulence that also draws air in.
Which gases can I use through a MIG regulator?
Regulators are made for particular gases, and the label or manual says which ones. Check that the regulator is marked for the gas you are using, whether that is argon, an argon mix or carbon dioxide.
Never use a regulator on a gas it is not designed for, as the materials, connections and pressure ratings differ. If a regulator will not fit the cylinder, do not force it or use an adaptor. Check the data plate and manual for your own regulator, or ask your gas supplier.
How do I read the gauges or flow meter?
Many regulators have two gauges. One shows the pressure in the cylinder, which tells you roughly how much gas is left, and the other shows the outlet setting, often marked in litres per minute. Others use a tube with a floating ball to show the flow.
Flow scales are made for particular gases and conditions, so use the scale that matches your gas and read a flow tube at the point on the ball the maker shows. Treat the figure as a guide. If you want to know the true flow, measure it at the nozzle. Check your manual for how your own regulator should be read.
What flow rate should I set for MIG welding?
A typical starting point for MIG welding indoors is somewhere in the region of ten to twenty litres per minute, but the right figure depends on the nozzle size, the gas, the welding current, the joint and any draughts. The machine or wire maker will often suggest a range.
More gas is not necessarily better. Too high a flow causes turbulence and can pull air into the weld, while too low a flow gives poor cover. Adjust within the suggested range until you get clean, porosity-free welds, and use screens against draughts instead of simply turning up the gas.