[icedvolvo]

Hi People,
I have a small job to do for a mate in stainless and normally would do this with TIG but its a shedload of tricky corner welds and I wanted to use MIG. It doesn't really matter what it looks like but strength is the main issue so .....

I have my pure Argon I use for TIG and my “SpeedShield 5/2” – Argon/CO2/Oxygen" I use for MIG.

Which of these is better for stainless MIG ???

Thanks for any advice.

[Edgewalker]

What do you mean by "tricky corner weld?"

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[icedvolvo]

What do you mean by "tricky corner weld?"

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Lots and lots of 10mm x 1.2mm box butted onto 6mm plate ... not hard but just painful ...

[Edgewalker]

http://m.lincolnelectric.com/en-us/supp ... etail.aspx

Some good info here.

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[Edgewalker]

I'm guessing you want short- circuit transfer. I would have never guessed 90helium/7.5argon/2.5Co2. Never mig welded stainless myself.

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[weldin mike 27]

Pure argon isn't used for anything except Aluminium. Other metals need a certain amout of active gas/ gasses to get the punch into the arc.

[cj737]

I've used 100% CO for stainless MIG personally. But, I'd probably still use TIG and 100% Ar and fuse weld that corners. One beautiful thing about stainless, its strong as can be once welded if the fit up is good. Get your heat right, large cup, and stroke!

My $0.0153 (accounting for currency exchange)

[Otto Nobedder]

Hi People,
I have a small job to do for a mate in stainless and normally would do this with TIG but its a shedload of tricky corner welds and I wanted to use MIG. It doesn't really matter what it looks like but strength is the main issue so .....

I have my pure Argon I use for TIG and my “SpeedShield 5/2” – Argon/CO2/Oxygen" I use for MIG.

Which of these is better for stainless MIG ???

Thanks for any advice.

Use the "speedshield" mix. Pure argon is very difficult to get a decent weld in stainless mig, even in flat position.

Yes, the ideal gasses are the helium mix mentioned above, and 98/2 Ar/O2, but your existing mix will perform far better than straight argon.

Steve S

[icedvolvo]

Hi People,
I have a small job to do for a mate in stainless and normally would do this with TIG but its a shedload of tricky corner welds and I wanted to use MIG. It doesn't really matter what it looks like but strength is the main issue so .....

I have my pure Argon I use for TIG and my “SpeedShield 5/2” – Argon/CO2/Oxygen" I use for MIG.

Which of these is better for stainless MIG ???

Thanks for any advice.

Use the "speedshield" mix. Pure argon is very difficult to get a decent weld in stainless mig, even in flat position.

Yes, the ideal gasses are the helium mix mentioned above, and 98/2 Ar/O2, but your existing mix will perform far better than straight argon.

Steve S

Thank u sir, that is the answer I was looking for If I cant do it properly I will revert to TIG but these structures are 4m long and difficult to get into "nice" positions for TIG, so a "point and shoot any angle" MIG is my easy method

[icedvolvo]

Just wanted to post my experience with using the Ar/CO2/O2 mix with stainless:

1: had to use higher voltage than expected
2: wire is very stiff, so keep your gun lead straight
3: with mild steel can clamp to the bench, but with stainless worked much better with clamp on material!
4: could achieve spray transfer but didn't penetrate well
5: welds were sooty on the outside but clean after brushing
6: ok penetration, steel bent in vice with no weld failure
7: small amounts of spatter after welding: was the stainless coated in something organic or was it the CO2 ???
8: not as pretty as TIG but much faster and easy for repetitive/tricky positions

20170327_121117.jpg (32.64 KiB) Viewed 2380 times

[weldin mike 27]

My adventures with solid wire ss it that its very finicky with the settings. Sometimes its great, but then sometimes it was horrible. I've seen a guy do the most fantastic looking welds, and then another guy lay pus on the same machine. Mine was one an old pulse machine with auto wire setting so it was a biatch to set.

Mick

[icedvolvo]

My adventures with solid wire ss it that its very finicky with the settings. Sometimes its great, but then sometimes it was horrible. I've seen a guy do the most fantastic looking welds, and then another guy lay pus on the same machine. Mine was one an old pulse machine with auto wire setting so it was a biatch to set.

Mick

Yeah that about sums it up! The tip about the clamp should be followed though, weld was much smoother when clamped to the work as opposed to my usual clamping on the table; stainless seems to much more finicky about a good clean circuit than steel or ally!