Mig welding gas choices... Need your real world input?

[DaveO]

This article...
http://en.wikipedia.org/wiki/Gas_metal_arc_welding
...has this to say about co2 content and spray transfer, which dovetails well with Ken's and Mark's posts:

"As the carbon dioxide content increases over 20%, spray transfer GMAW becomes increasingly problematic, especially with smaller electrode diameters."

The article doesn't specify what "increasingly problematic" means, though.

[SeanMurphy265]

75%/25% for mild steel,
I have used tri mix with mild steel, but that was given to me on accident. I believe it's more expensive per bottle.
100% argon for aluminum

[CGCINC]

75%/25% for mild steel,
I have used tri mix with mild steel, but that was given to me on accident. I believe it's more expensive per bottle.
100% argon for aluminum

Do you remember what the tri mix was? Did it weld smoother than the Argon/Co2?

[Brian Ski]

Thanks for the link to this post... Answers some more questions.

For the MIG I have have been using 75/25 Argon Co2 mix for steel. (That was what the LWS recommended) Been using it ever since. Pretty much all what I use it for (steel).

I did have to do some stainless welding and it worked as well as I could tell. Someone told me I could braze the stainless. Well that was a train wreck!!!! haha

[everlastsupport]

For MIG I use 75/25 Ar/Co2, my son likes Stargon (Prax air tri gas). The Stargon does seem to weld a bit better.

TIG is straight argon for me.