Selecting the right gas mixture for GMAW

[Joe Dillard]

Yesterday I stopped by a local welding supply shop so I could pick up a few misc. items and swap my MIG welders mix tank for a full one.

The empty tank I dropped off had a mixture of 80% argon, 20% carbon dioxide. I didn't realize till I got home that the tank I was given, has a mix of 75% nitrogen, 25% carbon dioxide. It's a light grey colored tank while the old one was reddish brown IIRC.

My question is; Does this switching of gas types (nitrogen from argon) make much of a difference for an amature welder?

While welding yesterday I found the metals to react and puddle differently and things seemed to be hotter than usual. The typical crackling sounds were almost non-existant, spatter dramatically increased, and deposits were notably higher. Things were just dog ugly! I MUST be doing something wrong!

Dummy me discovered that before yesterday I had been running regular wire (not flux core as I thought), and the welder was set-up properly for this ground connection wise. No errors there, just a mix-up on my part thinking that I had flux core wire when I indeed did not.

Then stupid me, swapped in a new 2# roll of flux core wire since I was about out of wire, and attached the new mix tank - and that's when things started to go south.

At first I thought it was the gas that started things to work wierd, but I decided to swap the leads & see what that did to things. Yep - it worked allot better after swapping the leads. Nice crackle sounds returned, but the welds were still crappy looking with lots of slag and spatter.

Am I missing something?

Here's a pic of the first weld I did after swapping tanks, and using the flux core wire with the leads wrong. <barf>

[NAILER341]

i'd take the bottle back for the argon mixture.

[Jeff Weston]

If you're using shielding gas, why not use the solid wire? As for the gas, I thought 75% Argon/25% CO2 was the norm. Take that with a grain of salt as I am the hackiest of hack welders.

[TObject]

Argon is noble gas, and more expensive. Physical characteristics of Argon and Nitrogen are very close, but chemically Nitrogen can react with some things (although it doesn't like to) while Argon does not react with anything at all.

[Joe Dillard]

Erik, I know with all my babbling above it may be hard to understand what I was trying to say.....but is there any particular reason to switch back - or do you think I simply got the wrong mixture and this is a bad thing?

Jeff, I've experimented with this a few different ways (some by mistake as mentioned above ). Solid wire seems to be better with shielding gas, although flux core does work.

Sergey, hmm, noble gas. Had to look that one up.

Main Entry: noble gas
Function: noun
: any of a group of rare gases that include helium, neon, argon, krypton, xenon, and sometimes radon and that exhibit great stability and extremely low reaction rates -- called also inert gas.

[Joe Dillard]

Thanks for the advice guys!

Well, the folks over at WestAir Gases & Equipment (formerly San Diego Welders Supply), in El Cajon, went out of their way IMO to make things right!

I stopped by there Saturday just before they were closing and explained to one of their folks the mistake at giving me the wrong gas mix. He gladly exchanged the small tank I had for a MUCH larger one free of charge! He apologized for the mistake and happily offered the much larger one even though I pointed out it was a much larger tank he was giving me.

Awesome customer service IMO!! I?ll certainly be returning there and giving them my business. I did end up picking up a few other supplies - prices seemed competitive.

Here's the new tank, I had a dinky one before.

[NAILER341]

Originally posted by Joe Dillard
Erik, I know with all my babbling above it may be hard to understand what I was trying to say.....but is there any particular reason to switch back - or do you think I simply got the wrong mixture and this is a bad thing?

Jeff, I've experimented with this a few different ways (some by mistake as mentioned above ). Solid wire seems to be better with shielding gas, although flux core does work.

Sergey, hmm, noble gas. Had to look that one up.

Main Entry: noble gas
Function: noun
: any of a group of rare gases that include helium, neon, argon, krypton, xenon, and sometimes radon and that exhibit great stability and extremely low reaction rates -- called also inert gas.

i guess i am a bit late on responding to this, but i was suggesting that you had the wrong mix. i am by no means a "welder" but have never heard of thenitrogen mix you have.

i am glad they took care of you.

[mrblaine]

Originally posted by Joe Dillard


Here's the new tank, I had a dinky one before.

still do

[Joe Dillard]

Originally posted by mrblaine
still do