Ok last year I did a complete SS exhaust on my car with my mig. After I finished the job, a couple weeks later, I realized that my weld were a little bit rusty... Oh oh... I welded all my nice job with a regular steel wire... ( yeah Im a newbie.. we learn from our mistake I guess.. )

So all my weld still really strong... I never take the car in winter or when it rain.

Now I have to do my DP... in SS. I will get the SS wire but do I need to change my gas ? I have a mixed bottle with argon in it + another gas that I dont remember his name...

Thanks for your help !

 

You probably have argon + co2.

For Stainless Steel your SUPPOSED to use a Tri-mix gas but im sure argon/co2 will work fine.

 

ok I will try it !

 

IF you use a CO2 mix, you will contaminate the weld area and it'll rust! You can't use an active gas to weld stainless. A trimix is what I use at home.

 

I've built a couple parts in stainless using 308 wire and 75/25 Argon/Carbon Dioxide. I live in Utah where corrosion is a serious problem but I have not had any corrosion problems after a year and a half on a stainless downpipe that I MIG welded.

I'm not doubting that the Argon/carbon dioxide mix is the wrong way to go however. I have had a lot of spattering issues MIG welding stainless and have been told the Tri-mix gas will help greatly with keeping spatter down.

You can't use the Tri-mix gas to weld Mild Steel because it will be too hot of an arc because of the helium, according to the local Praxair representative anyway. I tend to do mild steel stuff too which is the reason I didn't use the Tri-mix.

 

That could be, but I use my trimix for everything. Mild / stainless and have no problems.

 

Noob question: I just got a MIG welder (was using a SMAW welder before), and not sure on what gasses to use.

I want to weld aluminum, stainless, and mild steel. I have two empty gas bottles. What should I do...:

1 bottle of trimix and 1 of argon?
2 bottles of just argon?

Suggestions?

 

If Tri-mix will work just fine on mild steel...I'm going to be pissed.

Do you get a lot of splatter with the Tri-mix gas? Maybe it is just the way I am welding too, I have zero formal training. Pretty much just picked up a MIG welding machine and "Welding Essentials" book and started welding.

 

I used 100% argon on my stainless welds, came out perfect on the test piece, good penetration, good pooling and coloration.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flashmn &raquo;</TD></TR><TR><TD CLASS="quote">I used 100% argon on my stainless welds, came out perfect on the test piece, good penetration, good pooling and coloration.</TD></TR></TABLE>

i read that on licolns site as well.. My only problem is having 1 bottle of gas and not wanting to buy another.. aka blow $200

 

So for stainless, 100% argon is okay? I know that is the gas that you must use for aluminum. What about mild steel? Anything bad about using pure argon on it? It would be nice if I only had to pay for 1 bottle of gas. I got the bottles dirt cheap.

 

straight argon is pretty damn good for most of us backyard guys and mild steel doesnt really give a damn what you use for a gas in many cases. obviously if you are out to sell turbo manifolds, mig isnt the best plan.

pure co2 migging seems like more splatter and a weld that is more on the surface, blobby and built up you could say. switch to argon and the splatter all but goes away, weld lays in flatter, but ive noticed a lot more of my wire is just dripping right to the ground like a faucet leaking. i literally have had to be more careful about fires. still like the argon better, just off and on the trigger more on vertical pieces. i believe im using ER70S-2 wire or something to that effect in the mig.