View Full Version : Why C25 gas for MIG?

10-05-2005, 09:38 PM
I've been using C25 on my MIG for several years because that's what the guy at the welding store said to get and I haven't changed.

It works fine so I've never given it much thought until I got into this TIG stuff.

So what's the reason to use C25 with MIG and pure argon for TIG?

3 Phase Lightbulb
10-05-2005, 09:49 PM
You should be able to use 100% Argon with MIG, but I would expect you might not get sufficent heat with 100% Argon.

For MIG, you need extra heat and you are burning the electrode (wire) so some CO2 is good and probably gives you the extra heat you need. If you use C25 with TIG, I would expect the electrode to burn up too quickly.


10-05-2005, 09:54 PM
It's a little 135 amp machine so that's probably why they suggested the C25.

I'm still waiting for my argon cylinder to TIG. If I would have just leased a tank I'd be welding now. I had to get my own tank though http://bbs.homeshopmachinist.net//rolleyes.gif

3 Phase Lightbulb
10-05-2005, 10:01 PM
I use C25 (25% CO2/75% Argon) on my MIG machine. Go ahead and try C25 with your TIG machine. It's not going to hurt anything except maybe prematurely burn your tungsten -- no biggie. You can try C25, just expect the performance and weld quality to improve with 100% Argon.


10-05-2005, 10:05 PM
You'll use 100% Argon with your mig if you use a spool gun for aluminum.

10-05-2005, 10:16 PM
I'm just going to wait on the argon cylinder before trying out the tig. I've been fooling with it for a while so I can wait a few more days...

10-05-2005, 10:26 PM
I think that the carbon dioxide in the mix adds a little carbon to the weld itself. Lets you use low carbon wire that feeds easily but end up with a higher strength weld. At least that is what I remember from school twenty years ago.

10-05-2005, 10:26 PM
Better yet, go for 100% CO2 if you wanna do some welding. Or throw a little Oxygen (4%) in the argon. http://bbs.homeshopmachinist.net//cool.gif JRouche

The oxidizer (CO2 or O) helps with arc control and spatter with increased penetration. I dont recommend the argon/oxygen mix for thin sheet though.

10-06-2005, 03:54 PM
I use straight CO2, much better penetration and cheaper too. http://bbs.homeshopmachinist.net//biggrin.gif


Jim Koper
J&R Machining

10-06-2005, 06:29 PM
CO2 is cheapest.. but its dirtier. generates alot of spatter

straight Argon is ideal, and whats used for both MIG alum&stainless, but its more expensive.

the C25 mix is a decent balance between price and quality.

i dont think either of those two gases will have any effect at all on your bead composition or weld strength.


10-06-2005, 06:38 PM

Read here. Craig answers all. -Doozer

10-06-2005, 07:23 PM
I use a c25 mix myself when TIG welding mild steel at times. I used it doing MIG welding as well. It migs a little better on mild steel than pure Argon does like what was mentioned earlier. It is a compromise to me either way you look at it. Pure CO2 does better for MIG for me as well as pure Argon does better for me doing the TIG, but the C25 mix does ok with both and the arc is stable. Like what was mentioned earlier about the Tungsten getting dirty quicker is very true.

3 Phase Lightbulb
10-06-2005, 08:23 PM
Hey, this looks familiar http://bbs.homeshopmachinist.net//smile.gif