Gas mixes

[hankj]

Once more into the fray:

In another thread (sorry, I'm not "board-smart" and don't know how to link a thread - mebbe I getta hep?)I was talking settings on the MM135 with DDA52. I use straight CO2, but the door chart numbers suggest I could weld "hotter" with C-25 - the wire speed is much higher for the Ar mix. What happens with 84/16? Is the gas mix that significant in determining weld parameters? If I can run my wire speed at a dial setting of 60 on a mix, it suggests to me that I can put a lot more heat (i.e. amps) into the weld. True or not?

Educate the uninformed, if you please!

Be well.

hankj

[DDA52]

hankj
If I'm not mistaken, you're welding just as hot or maybe a tad hotter with co2 @ 10/40 than I am @ 10/60 with c25. It is my understanding that c25 is a "cooler" gas than straight co2. The end results should be relatively the same even though the settings are different. If I'm wrong, somebody educate me please.

Don

[Paul Seaman]

They give different settings to come up with the same finished product using acceptable gasses by how the gasses react with the weld metal. The c25 and co2 will provide the same input if you use the settings by the chart for the appropriate gas. Each has its benefits, discuss this with your supplier and maybe he will help set you up a sample run on your next exchange or refil, never hurt to ask!

Is this any help,

[hankj]

Thanks, guys. Pjs, of COURSE it's a help. You guys always help - that's why I love this board.

I've pretty much decided to go to a 210 this summer. When I do, I'll set it up with either C-25 or 86/14 on one side and 100% Ar on the other for aluminum. Later, tri-mix for SS. I'll leave the 135 set up on CO2 and stick .023 wire in it for small stuff, and it'll be Nirvana in the Gadget Garage!!

If I hit the lottery, there'll be a Spectrum 375 in there, too.

Be well.

hankj

[MAC702]

I switched gas dealers when I went for my C25. Turns out Airgas only offers the C16. I like it. I use the same settings as for C25 and it works fine in my MM175, though I haven't gotten to do much testing as my MM175 is still awaiting a new MIG gun, but I finally got Andy my address for the new one.

Hey, Andy, Any chance of getting it autographed by John Andretti?

In my PowCon, it short circuits fine, though I've never tried it with any other gases as I got the .045 solid wire at the same time as the new gas. But it also sprays with this same gas, though only in a narrow margin of settings based on my limited experience.

[hankj]

Why use mixes?

Well, y'all,

Soudns like CO2 is the "hottest" shielding gas for mild steel. If so, why use anything else? Is spatter the issue? Is controlling the HAZ the issue?

Having never used a mix, I don't know what my welds would look like, but they look pretty clean now. There is some spatter, but at V=8, WS = 35, I'm doing pretty clean work on 3/16 and smaller stuff with the MM135.

Think I'll talk to the man and see if I can't borrow a tank of C-25 or something and see what the difference is.

Someday, I'm gonna learn all this magical stuff. Wish I had started 20 years ago...

Be well.

hankj

[cope]

With the 135 I would stick with either C)2 or C-25.

[MAC702]

For many years I never bothered with switching to an argon mix because I was very happy with the results from 100% CO2 from my MM175. Only after getting a PowCon did I really feel it was worth it because I might have the ability to spray transfer with a mix. Turns out, the C16 from Airgas will spray from my PowCon within a very limited range of settings. It does recommend 98Ar/2O, though. I have a feeder for my Trailblazer, too, but haven't swapped things over to try it yet. Anyone else done any spray from a Trailblazer with .045 wire?

[ASKANDY]

Hankj-

Basically the mix gas will give better puddle flow and not nearly as much spatter. This is at a cost of pure penetration. The CO2 is a reactive gas that gives a deeper root penetration but usually a narrower bead profile that may lead to undercut at the toes. The addition of Argon will wet the toes out better and give less root penetration which when welding thinner material is better as the chance of burn through is reduced when going with the mix gas. The higher the Argon %, the less penetration you will get. There is a happy medium as if you try to go with 100% Argon to weld steel, you will get a bead that is ropey and has low penetration. You need a small amount of CO2 to increase the heat to help the puddle penetrate properly. As you stated before, CO2 is a hotter gas. This is why you would use a higher voltage to weld the same thickness with CO2 and a lower voltage with AR/CO2.
Example:

1/8" steel
approx 20-21 Volts for CO2 and 17-18 Volts Ar/CO2

Hope this helps

Andy