Mig gas mixture

[Chile99]

Allen, I would like to hear of any experience, thoughts running tri mix, Co2, Argon, Helium with mig in regard to spray phase work. Thanks
John

[Allen]

Exactly what is it that you are trying to accomplish?

As a general rule, the transition from globular transfer to spray transfer depends upon the wire diameter and shielding gas used.

Normally for mild steel a gas mixture containing more than 15% CO2 will not allow the transition phase to occur, and spray transfer is impossible.

Also, I do not believe helium or a tri-mix can be used. I have no experience with that, but I've been wrong before. Come to think of it, I don't think I've ever seen an argon/CO2 mix used for spray transfer either.....

Generally a 98% Ar 2% O2 mix is used on thin mild steel, 99-1 on thicker steel and stainless, and 100% Ar on aluminum, copper, and bronze. All of my experience has been with 100% argon on mild steel.

There are also minimum current values your welder will need to achieve to sucessfully transition from globular to spray. Make sure your power source is up to snuff.

So what is it you're doing?

Allen

[Chile99]

Was at the local air gas supplier getting 75-25 mix (Argon 75%/CO2 25%) Talking to the guys behind the desk about getting a flatter bead profile for 1/8 carbon steel and working in spray transfer mode. They felt a argon, CO2 helium mixture was a good way to go. And cheaper than straight Argon. Never heard of it myself. Stated lower amperage to attain this mode and user friendly shielding mix.
As far as my Miller machine it has it's own dedicated 220 volt feed. We used a few different gas mixtures for mig shielding at the shops, 75 argon 25 co2 was the day in favorite, we had a few processes certified with 80/20 and one with a tri mix that didn't contain helium. But helium was the shielding gas Linde started the tig process with during WWII. I started welding 40 years ago on a Lincon toumbstone with the copper windings, lots has changed since then.
What is it I am doing? Trying to duplicate some of the surface quality the German Crane technicians were were doing in the workshops. The robo welders I am not talking about, although impressive. Some of the fabrication was done by fellows who knew how to make it to international certs and make it look quite seamless. They were doing sheet metal and structural tubing work. I never could find a window to spend some time with those guys.
John

[Allen]

Originally posted by Chile99
Was at the local air gas supplier getting 75-25 mix (Argon 75%/CO2 25%) Talking to the guys behind the desk about getting a flatter bead profile for 1/8 carbon steel and working in spray transfer mode. They felt a argon, CO2 helium mixture was a good way to go. And cheaper than straight Argon. Never heard of it myself. Stated lower amperage to attain this mode and user friendly shielding mix.
As far as my Miller machine it has it's own dedicated 220 volt feed. We used a few different gas mixtures for mig shielding at the shops, 75 argon 25 co2 was the day in favorite, we had a few processes certified with 80/20 and one with a tri mix that didn't contain helium. But helium was the shielding gas Linde started the tig process with during WWII. I started welding 40 years ago on a Lincon toumbstone with the copper windings, lots has changed since then.
What is it I am doing? Trying to duplicate some of the surface quality the German Crane technicians were were doing in the workshops. The robo welders I am not talking about, although impressive. Some of the fabrication was done by fellows who knew how to make it to international certs and make it look quite seamless. They were doing sheet metal and structural tubing work. I never could find a window to spend some time with those guys.
John

John,

I don't know what to tell you about the bottle monkeys' suggestion, I've never heard of it either.

I would pick a wire, and the go with exactly what the manufacturer suggests as a shielding gas for spray work. Then fine tune it from there.

I'll ask our guy next time he's in the shop what he'd recommend. Maybe the tri-mix is something new for spray? I don't know.....

Do you have a pulse machine available?

I ask because as I mentioned, all of my mild steel spray spray work was done on a pulse machine with straight argon. As far as I'm concerned, that'd be the way to go.....

I also have a nifty spray transfer story to share with you that I'm particularly proud of. It involved removing a "bad" section via carbon arc, in an uninterrupted weld around the circumfrence of a can, and patching it.

Anyway, I'll help all I can.

You do know that I'm EU certified?

Allen