MIG - 100% CO2 or 75%/25% Argon/CO2

[DavidSim]

Hi everyone,

I ask for your advice regarding the gas to use with my new Lincoln 180 MIG, the manual says I can use 100% CO2, or 75%/25% Argon/CO2 mix.

I would be welding Mild Steel only, thin stuff like body metal, and sheet/tube up to 1/8 inch mostly.

I have a bottle of 100% Argon, so I gave it a whirl (flow setting in the 30-40 range), did not seem to work out too well (although my limited experience is probably most of the blame).

What gas do you folks use with your MIG, when welding Mild Steel?

Regards to all.

[dstevens]

Argon 100% with mild steel mig is a no go. I use 75/25 or Airgas "Steelmix" with IIRC is 85/15. Depends on where I swap the bottle. Search around the forum, there is a bunch of info on gas.

[sn0border88]

Your going to want to go with a 75/25 mix, also known as C25. 100% CO2 is going to provide a more violent and hotter arc which would pose problems on thin material.

[DSW]

Originally Posted by sn0border88

Your going to want to go with a 75/25 mix, also known as C25. 100% CO2 is going to provide a more violent and hotter arc which would pose problems on thin material.

Agreed. 100% CO2 is usually used to help give a small boost in penetration to 110v migs over C25. You will need an adapter to change the reg fitting to fit a 100% CO2 cylinder.

[galencwi]

Keep in mind different wires and metals weld better with different mixes of gas.
For you if your just going to be doing basic welding like solid wire for steel then like
sn0border88 said use the 75/25 and you can turn your regulator down a little too.
Use 90/10 if your looking to go to spray arc on the heavier stuff (My fav!)
Aluminum Mig usually straight argon
Dual shield wire (Flux Core) thats the time for 100% CO2
Innershield wire ..... none needed lol
Stainless Steel usually a tri mix and theres a few variations that work.
I take notes so I know what worked best for me and my welder.
The guys at Airgas and Quimby welding supply are usually pretty knowledgable especially when it comes to welding specialty stuff.

But the guys here have been there and done that so dont be afraid to ask.

[sn0border88]

Originally Posted by galencwi

Dual shield wire (Flux Core) thats the time for 100% CO2

This is dependent on the type of wire used, some require 100% CO2 while others use a Ar/CO2 mix. When looking at the wire specification it will have a C or and M at the end to denote the gas required.

Ex: E71-T1-M

[dstevens]

Airgas around these parts quit selling C25 a few years ago or so.

[sn0border88]

Originally Posted by dstevens

Airgas around these parts quit selling C25 a few years ago or so.

I find it VERY hard to believe that a welding gas supplier doesnt have 75/25. Or are they just trying to push their proprietary mixes?

[Matt_Maguire]

My neighbor uses Airgas and they have 75Ar/25Co2 ?

My Praxair guys have been pushing the 15%Co2, but with the repair guys it's a total bust, things have to be clean, clean clean.

Matt

[Sandy]

At our Airgas here there's hardly a word spoken, unless you just want to make conversation. Set an empty c25 at the door and that's what they'll have setting there when you leave. I'd have to speak up early and specifically ask for something else to get it.

[norite]

C25 = 75%Ar/25%CO2

This is what you want to use for thin steel with MIG.

[DavidSim]

Thanks everyone,

based on the information provided, I am going to go with the 75/25 mix.

Regards to all.

[dstevens]

Originally Posted by sn0border88

I find it VERY hard to believe that a welding gas supplier doesnt have 75/25. Or are they just trying to push their proprietary mixes?

You can find it however you like but the local Airgas dealer doesn't offer trades of C25. They stock 3 blends of proprietary "Steelmix", 2 tri blends and an 84/16. C25 is in the catalog, I suppose I could order it but when you go into a non fill dealer in this area, they don't have any. Prax and the local non chain guys stock it though.

[galencwi]

[quote=sn0border88;475911]This is dependent on the type of wire used, some require 100% CO2 while others use a Ar/CO2 mix. When looking at the wire specification it will have a C or and M at the end to denote the gas required.

Ex: E71-T1-M[/QUOTE

Thanks for pointing that out.