Best gas mix when Mig welding mild steel

by Eric Brandenburg
(Ashland, Ky USA)

I was asking the local Miller dealer what was the best gas mix to use when welding on car parts and pieces. He said to strictly stay with 75% C02/25% argon. Umpteen years ago we hired a kid from Morley cooling tower company to work at the refinery. The welders had just received their 1st Mig machine this was in the middle 70's. They wouldn't use it because they had so much trouble with splatter. The FNG that had just come to work with us, told us to get off 100% Co2, and switch to 85% Co2/15% argon. It was a difference between day and night. Sometimes change is very difficult, especially when you have the blind, leading the miss-inforned. When we questioned our welding equipment sales person they had no idea, other than thats what they had heard or read somewhere.

What is your pick for gas blends and why? Thanks in advance for you input..................Brandy


I typically use 75/25 ar/co2 but only because its easy to get.

I keep an open mind. But I know if I walk into a local welding supply and ask for 85% co2 25% argon, they are going to look at me like i have 2 heads...and I wont walk away with any gas ..they will have to custom mix it for me.

There is a site called that really harps on welding sales people pushing gas on us for no good reason....

I dont usually have trouble using standard 75/25 but I think there is always room for improvement.

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Nov 19, 2015
Welding exsperienz NEW
by: Anonymous

May same body said I em crazy. But. I have snap on Mig welding 3500 hd pro Mig welding I run out gas mix 75to25% mix I was far for the supply I have tank for alluminium. 100% argon. Guess what work much better then mix 75to 25% just add little bit more pression on gauge the welding is melt like butter & flat clean

Jul 21, 2015
C02 mix gases NEW
by: Anonymous

We used to have Hocon mix us a 65/c02 20/argon and 10/hydrogen the results were a hot flat bead with almost no splatter…. Costly but worth it in a production environment

Jul 01, 2015
might gases NEW
by: Anonymous

Has anyone ever used 95/5 mix?

Nov 24, 2013
mig gas NEW
by: scot

Recently purchased a smith mixer co2 argon. I have been welding with only co2 for years only because I am too cheap to upgrade.75 argon 25 co2 is the way to go because it is readily available;less spatter than co2 alone and penetration is fine with 75/25.if you want less spatter more argon-$$$.100% argon does not work.

Jan 09, 2012
85/15 gas for spray and regular MIG NEW
by: Bill Baedke

I have a machine set up for .035 steel wire that I wanted to be able to use spray transfer on thicker material, but still use regular transfer (short circuit?) for vertical and thinner material. The local welding supply here in Romeo, MI got it for me from their main plant in a couple of days. It seems to work well for both by adjusting the volts/amps. The machine is an older Lincoln CV300, which normally should have 3 phase power, but we don't have it, so we wired it up to run on single phase. Less total output, but I am limited to 60 amps input at 240 volts (it is my house). I can get up to about 200 amps out at about 25 to 30 volts. The spray transfer is really nice on 3/8 or 1/2 inch thick, lots of penetration, and it welds nicely on thinner matl like 1/16 or 1/8. Otherwise, like Jody says, the 75/25 would be perfect for regular MIG and readily available.

Jan 06, 2012
Mig Gas Blends NEW
by: Eric Brandenburg

I'm sorry Jody, the blends should have been 85% Argon/15% Co2. I promise to proof read any future questions I ask? With all of this said, the blend we got from our supplier after the change, was very close to your 75/25. We probably would never have seen any difference from what you use.......Brandy!

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