Best options for MIG gas
Since MIG welding traditionally uses short circuit transfer for light and medium welding chores, 75/25 shielding gas is typically the most common you will find on the market. But there are other options out there for you Everlast Power i-MIG or PowerMTS welder. Most all Everlast Power i-MIG welders have an arc force adjustment. The arc force adjustment is similar to a slope adjustment in a transformer based MIG welder. This means that the welders can be “tuned” to meet certain desirable arc qualities with varying types of MIG shielding gas.
The biggest benefit of that is that these welders excel at running straight CO2 (carbon dioxide). Ordinarily on many modern MIG units without variable arc force control, CO2 is dreaded as it is smokey, spattery and all around generates dull and oxidized looking welds. It is much cheaper than a 75/25 Ar/CO2 blend.
With the arc force adjustment, this ornery behavior can be cleaned up and can force CO2 shielding gas to behave itself. While still not as appealing as a 75/25 mix of Ar/CO2, it is quite close in quality if the arc force is properly adjusted. Now there are other blends of Ar/CO2 as well that should be mentioned that have value. A personal favorite is an 82/18 proprietary gas from Airgas/Air Liquide. This blend offers the ability to weld short circuit or spray transfer. A 75/25 gas is only able to offer (competently) a short circuit arc. But once the percentage of argon increases to 80 percent controlled spray transfer is possible. Increase it at all above 80 percent and it improves the ease at which it will spray cleanly. Go to 90% and above Ar, the suitability for short circuit is diminished.
Of course, a 90/10 mixture of Ar/CO2 is a great spray gas mix for mild steel, it does not like to penetrate well with short circuit. This is true for other spray gas mixes as well, except for the 82/18 and the 80/20. The 80/20 though will require a higher voltage to go into spray transfer mode, so this is not suitable for lighter gauge materials and the weld may become too hot to control in some situations of spray transfer.
Returning to the 75/25 gas, this mixture is fairly economical in cost and is excellent for use with mild steel in short circuit transfer with welders 210 amps and under. It is popular because it is good at what it does. You will end up with a relatively clean and spatter free weld. But if you are using a larger welder there are other gas options if speed and efficiency are of concern.