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Gas for Stainless

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Gas for Stainless

Postby Chips O'Toole » Thu Feb 02, 2017 3:24 pm

Do I need a helium mix for welding stainless, or is my usual argon/CO2 okay? Seems like I get a lot of spatter.
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Re: Gas for Stainless

Postby Coldman » Thu Feb 02, 2017 3:43 pm

Has to be pure argon for stainless


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Re: Gas for Stainless

Postby Chips O'Toole » Thu Feb 02, 2017 4:34 pm

It sounds like I'm going to need a whole bunch of tanks if I want to use both MIG and TIG on ferrous metals, stainless, and aluminum.
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Re: Gas for Stainless

Postby cj737 » Thu Feb 02, 2017 4:56 pm

Chips O'Toole wrote:It sounds like I'm going to need a whole bunch of tanks if I want to use both MIG and TIG on ferrous metals, stainless, and aluminum.


You can do it all with 2: 100% Argon to TIG steel, aluminum, etc. 75%/25% MIG for steel, 100% Argon to MIG aluminum.

Helium is not required, but helpful with Aluminum TIG.

I use 3: 100% Argon, 100% Helium and a 75/25 for steel MIG. I use a Y connector on the TIG to allow any ratio of He with the Ar.
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Re: Gas for Stainless

Postby Chips O'Toole » Thu Feb 02, 2017 4:59 pm

That is really helpful. Thank you.
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Re: Gas for Stainless

Postby Otto Nobedder » Fri Feb 03, 2017 11:05 pm

MIG welding stainless steel can be done with 75/25 Ar/CO2 as with mild steel, but you've already noticed the spatter, and the color is dark. 98/2 Ar/O2 makes better welds. I personally prefer tri-mix, 90/7.5/2.5 He/Ar/CO2, but the customers spec it, and pay for it. (Also, our customers make it, so they're basing the choice on an engineering decision.)

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Re: Gas for Stainless

Postby Chips O'Toole » Fri Feb 03, 2017 11:15 pm

I found a dude on Craigslist selling 125 cu. ft. argon tanks for $120, so now I have one in my garage. We'll see how it works.
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Re: Gas for Stainless

Postby Chips O'Toole » Mon Feb 06, 2017 9:45 pm

I was about to try using the pure argon with stainless, but I saw a Youtube video where some guy said MIG-welding stainless with pure argon gave really bad results. Is argon really the way to go? I will eventually need the bottle for TIG anyway, so it won't be wasted, but I would like to use the right thing for MIG.
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Re: Gas for Stainless

Postby Coldman » Mon Feb 06, 2017 10:26 pm

At welding school we used 100% argon for thin 304 when migging. Seemed OK at the time. Maybe the school didn't want to bone up for expensive gases.

Miller site says use trimix only.

Our big gas manufacturer here in Oz says to use:
Stainshield for up to 1/4" thickness - 98.5% argon and 1.5% oxygen
Stainshield Heavy for thickness greater than 1/4" - 35% helium in argon + 2.5% carbon dioxide.

Personally I think C25 would be a mistake as there would definitely be carbon pickup altering the composition and properties of the surrounding parent and fill.
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Re: Gas for Stainless

Postby Coldman » Mon Feb 06, 2017 10:56 pm

If its getting too complicated the other alternative is that there is now a gasless fluxed core wire available:
https://www.amazon.com/Blue-Demon-stain ... B00G5GHUBU
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