Welding with carbon dioxide?

[djjsr]

I've heard from an unreliable source that it's possible to mig with CO2 instead of argon. Anyone know if this is true?

 

[Zrexxer]

I've heard from an unreliable source that it's possible to mig with CO2 instead of argon. Anyone know if this is true?

Of course it's true. It's used with solid wire for short-circuit transfer applications, as well as being used with some dual-shield wires for very high deposition. And you'd never use pure Argon for a MIG process anyway, you need a certain amount of active gas. C25 (75% Ar/25% CO2) is typically used.

CO2 can produce a little more spatter than less active gases but depending on the machine much of it can be dialed out.

The good thing about it is that it's cheap and a 20 lb CO2 cylinder yields hundreds of cubic feet of gas.

This weld was done with .030 wire in a Lincoln 175 unit with 100% CO2:

 

[speed bump]

I hope you meant 75/25 and not straight Argon. Personally I haven't used very much CO2 but from what I remember from "the bible" you get more splatter and slightly more penetration.

 

[djjsr]

Thanks guys. I'm gonna give it a try. Just trying to save a few bucks.

 

[Diesel_Crawler]

I hope you meant 75/25 and not straight Argon. Personally I haven't used very much CO2 but from what I remember from "the bible" you get more splatter and slightly more penetration.

Ding ding, you win.

75/25 is still IMO better then CO2. If you want more pen, push up your wirefeed speeds or adjust other setting first.

 

[rsanter]

I hope you meant 75/25 and not straight Argon. Personally I haven't used very much CO2 but from what I remember from "the bible" you get more splatter and slightly more penetration.

I thought the CO2 gave better 'heat' or penetration than the 75/25

bob

 

[MottsRods]

Using str8 Co2 will get you better penetration. Using a 75/25 mix will all for a more finessing weld bead and a little less spatter. It will mainly depend on your welding style as to which you will prefer. Are you a lay the heat on it and burn it in fast, or are you a moderate heat/slower wire speed kinda guy to allow the parent metals to fuse better as the heat disipates into the weld and not into the air. Sounds way too thought out, but it it's true. If your a newbie to welding, I suggest you starting with str8 Co2, as it will allow you to get better penetration until you learn how a good strong weld looks and how it feels as your making it.

 

[speed bump]

I thought the CO2 gave better 'heat' or penetration than the 75/25

bob

Thats what I was saying but I didn't quite finish the sentence.

 

[drive em]

I still do all of my MIG welding with CO2, and I think that for the money, It cannot be beat. I use a little anti spatter spray on the material and on the gun and I do not have any clean up to do. I use an L-Tec (formerly Linde, and now Esab) 225 amp machine that I bought new 22 years ago and it is the best MIG that I have ever used bar none. It has also been in constant use building hundreds of 9" Ford rear ends, and hundreds of roll cages. I would buy another just like it in a second if I could find one.

 

[cwstevens92]

CO2 is fine dialed in right and using anti spatter spray or dip as drive em mentioned. I personally use 75/25 for carbon, 100% argon for aluminum and 85/10/5 for stainless

 

[Merkava_4]

You guys running straight CO2 - are you pushing or dragging?

 

[nissan_crawler]

I've ran both. Not a huge difference either way, I did notice less splatter with the mix, though.

 

[Zrexxer]

I run a push on most solid wire for better puddle visibility.

 

[rsanter]

I have both tanks

I use the mixed gas for welding sheetmetal, car bodies, etc. generally thinner stuff

for general fab of thicker material I use the CO2

bob

 

[wreckercologist]

We used to use Co2 at work. It was fine as long as you didn't mind the spatter. The mix we use now does make for a cleaner weld as far as spatter goes.

Position doesn't seem to matter much, at least I don't remember any issues. Push or drag, it was about the same.

rsanter makes a good point. It might be more cost effective, or make for better welds to have a bottle of each, but for the average home user that would be kinda expensive. You could probably justify it to the wife with: you know how we have four kinds of salad dressing in the fridge? Well, we need two kinds of shielding gas for the same reason. You see, ......................

 

[Bigrhamr]

Years ago I had a Lincoln rep illustrate the oversimplified difference this way:

2 beads, same material, same speed, same wire, same gun angle, no oscillation.

Looking at the beads from the end the one with straight CO@ will be an oval
standing on end, more weld bead height both above the surface and penetrating into it.

The bead with Argon blend will be flatter, an oval laying flat if you will. Less weld bead height both above the the surface and penetrating into it.

For what it's worth.

 

[dlwilson]

I use something called "Stargon" because that's what they have at the local welding supply. It's 90/8/2. The guy at the counter claimed the O2 makes it "burn hotter" so you get better penetration. It works okay in my mig.

http://www.praxair.com/praxair.nsf/AllContent/EB1882A4B28BD23F85256E750065759A?OpenDocument

 

[Stinger]

These welds are all done with CO2, I don't use Argon because it's so much more expensive and it didn't take but a few minutes to learn how to weld just fine with CO2.

 

[djjsr]

Looks good Stinger.

Anybody know if the regulator for an argon bottle fits a CO2 bottle?

 

[Migsince82]

You'll need an adapter. Got mine at Airgas. You best bet is to bring your tank there so they know exactly what you're dealing with.

~Miguel

 

[Lippyp]

Over here its quite common for people to use whats known as pub gas, basically the bottles supplied to bars to power the beer pumps. Cheap to get hold off if you know a friendly pub landlord.

 

[Kjbakke2]

I thought the CO2 gave better 'heat' or penetration than the 75/25

bob

using straight Co2 gives you better penetration but is notorious for being harder to control on the thinner side of things.....you blow through much faster and easier which is why almost everybody starts out on a Co2 Argon mix