Argon and MIG ?

[Zeke]

I have a bottle of Argon that somehow got here from the Midwest years ago from a welding supply that is no longer in business. I think they were bought out. Anyway, it's doubtful that my LWS will exchange it. So I'll just burn it up and forget it. I'm outside welding on a gate. The TIG isn't working too well because I can't get out of the breeze. I tacked everything up with FCAW. Turned my little Thermodyne inverter around a did the hinges with rod. But now I need to go over everything and seal it up so water doesn't rust my gate out from the inside.

Here's the question for you real welders, not just some guy like me that answers others welding questions sometimes good and sometimes not so good. I understand that pure argon and 302 stainless wire are the way to go using GMAW on SS. I also know that stainless SMAW rod can make some pretty nice welds on mild steel. So, can I conclude that 302 wire with argon will weld mild steel using my MIG?

OK, sure it will. I mean I didn't ask this question w/o reading up. Argon and GMAW using typical ER70S produces a taller weld with less penetration. This is a gate, not a race car. However, I also happen to have a spool of 302 wire that will probably never get used. I can burn these 2 surplus materials and be done with them.

So, how 'bout it?

 

[Thumper68]

Should work just fine, I would run a few test beads to get the settings right, however you are going to have the same issues with the wind, if this is the best way to go then you should get a tarp and construct a tent to weld in blocking the wind.

As far as the tank goes I would check around the LWS I use will take in any tank I bring them as long as there is no damage, if it is out of date they charge me a bit more.

 

[Zeke]

Thanks. I was going to run the tank by Air Gas whenever I need to go get one of my other 4 tanks filled. (O2, Ace, another Ar and my usual 75/25) Can't hurt to ask.

Yeah, I thought of some plywood and such for a wind (breeze) break but it's a lot of trouble. I will use FCAW and dress things up a bit with a grinder before I go to extremes. You might ask why don't I just take the gates down and do them in shelter and that would be an excellent question.

That's probably what I'm going to end up doing. But this argon and 302 SS thing would be good to know.

 

[brownbagg]

argon for aluminium

 

[CGT80]

There is a local shop that will fill my brother's tank, but will not exchange it due to a neck stamp. It was out of code last time, so I had another place test it for 40 bucks and then the welding shop filled it from a bank of tanks. They have a filling plant in the back of the property and just exchange out customer owned bottles and refill in the back. This works out fine for us since this place has the best gas prices, but it does prevent us from taking that bottle to airgas.

x2 on test beads. Maybe weld a joint in scrap and do a bend test to see if it cracks or holds up to what you throw at it. A gate shouldn't see too much stress if it is built right. My backyard gate probably weighs over 1,000 pounds with the engineered fence boards, but it is 30 feet wide and moves on 5 or 6 roller wheels on a section of angle iron. The force is mostly downward.

What will happen if your gate does fail? If the result wouldn't be a big deal, then the risk is low. If it meant that someone could get seriously injured, then maybe you should use standard procedures and buy the correct materials, if unsure of using up what you have.

Did you try to build any kind of wind block or shield to protect your gas?

 

[Zeke]

No wind block, I was lazy. I'll pick up my pace tomorrow. It was an academic question. If you know something....

 

[kf4zht]

I've run quite a bit of mig on straight argon. It is less penetration but not amazingly less. Turn the heat up a little and wire speed down to compensate.

Most of the people who freak out have never tried it and go off what some instructor told them.

 

[sberry]

Real welders would stick weld it.

 

[Rookie2]

Wouldn't the 302 cause the steel to crack because of removing carbon from the steel ?

 

[zmotorsports]

If you are after aesthetics you won't be able to get it using straights Argon with the MIG (SMAW) process. The gas for MIG welding should contain some CO2 in order to help conduct the heat, that is why the C25 (75%Argon/25% CO2) is preferred. The weld will not look very good and a high chance of severe undercutting.

If you are going to be welding this outside then the same "breeze" conditions will exist with the MIG as if you were to TIG weld them, so some barrier will be necessary. Personally, I would set up a small wind block/barrier and TIG (GTAW) weld it and get both good penetration as well as a nice looking weld out of it.

Mike.

 

[kkroger]

Aluminum foil to form a dam and wind break....

 

[pepi]

I've run quite a bit of mig on straight argon. It is less penetration but not amazingly less. Turn the heat up a little and wire speed down to compensate.

Most of the people who freak out have never tried it and go off what some instructor told them.

Not big on instructors myself, just like teachers. What's that saying, those that teach cause they can not do.

However other resources suggest a mix for mig welding.............. to mention a few small no nothing companies, Miller, Lincoln, and Hobart ........

Just saying, no freaking out here.....

 

[Zeke]

------------------------------- Turned my little Thermodyne inverter around a did the hinges with rod.------------------------------

Real welders would stick weld it.

So I guess I'm only a real welder when it comes to hinges?

 

[MoonRise]

Pure argon is the correct shielding gas for GMAW on aluminum. Or GTAW on almost anything and everything.

It is NOT the correct shielding gas for GMAW on steel (plain or stainless steel).

If you want to use up that argon, use it for GTAW.

Any gas shielded welding process (GMAW or GTAW) needs to not have the shielding gas blown away during the welding. Set up some sort of windblock if doing a gas shielded welding process outside (sometimes, even 'inside' there can be enough of a breeze or draft to mess up the proper 'blanket' of shielding gas that you need for GTAW or GMAW).

As to using argon and some 302 wire to do GMAW on plain steel, why? Just use your usual C25 or straight CO2 (for short circuit transfer mode GMAW) and plain ER70S6 (or S2 or whatever) mild steel wire. This way you are also using 'known' materials and 'known' welding parameters instead of trying to come up with some witch's brew that might (or might not) work.

And your statement of

I understand that pure argon and 302 stainless wire are the way to go using GMAW on SS.

is not quite right either.

Stainless steel is 'different' than mild steel. For 'proper' welding of stainless steel, you really do have to get the 'proper' filler/electrode stainless alloy to go with the specific alloy stainless steel you are trying to weld.

For welding common 304 stainless, you use 308 filler.

For welding 302 stainless, you use 308 filler.

For welding 316 stainless, you use 316 filler.

For welding various stainless steels to mild steel (tank cladding or such), 309 filler is usually used.

etc, etc.

(I can't even find a 302 stainless electrode listed. Must be some 'old' stuff. The only '302 electrode' that some google-fu found was a euro shipping company stick electrode that is actually an AWS 6013 rod, UNITOR GPO-302N.)

Shielding gas for GMAW on stainless steel is usually tri-mix for short circuit transfer mode welds and 98-2 argon-O2 for spray transfer mode welds.

Doing short circuit transfer mode welds on stainless steel using C25 sort-of works. But you end up with excess carbon (from the CO2) transferred to the weld puddle and now your stainless steel is no longer stainless (and WILL rust faster/more). If it didn't need to be stainless in the first place, why did you use stainless filler (typically more $$ than plain mild steel filler) at all? If the parent material is stainless, then weld it using the 'proper' stainless filler and the 'proper' shielding gas for welding stainless so that the parent material and the weld bead are still actually stainless.

You can (sort of) weld steel using a coat hanger (use a steel one though, the plastic hangers don't seem to work too well ) as filler. But why? Use the 'right' filler/electrode for the job and be more assured of doing a 'good' job.

 

[APEowner]

I can't help with the can I get away with the gas/filler question but I can tell you that I have had some success with cranking up the gas flow when welding in a breeze with the MIG.

 

[Zeke]

Moonrise, I may have to go look at that spool again. I had a SS muffler and exhaust on a car a decade ago when I got this wire. It was supplied by the manufacturer (and welding instructor) that had a side business making aircraft and subsequently air cooled car engine mufflers. I don't know what grade the muffler was. That's a nice tutorial you posted. I actually read some of that on the ESAB and Lincoln sites earlier this morning.

As for the welding. I caught a break in the breeze early today and welded out most of what I have to do. It isn't pretty because there was a lot of contamination. I know how to to the right prep but I get lazy and just want to light up an arc. The shops that build gates and other ironwork around here all use FCAW and it shows. Only the highest custom guy would go to more trouble. Why do I bring that up? It's not that I strive to be just like the average shop, but no one looks at these things closely and no one really cares. My personal satisfaction lies elsewhere.

And the fact is, I do actually like FCAW. I'd like to be really good at that. I may go get some quality flux core wire as I'm just about out.

Update: I did go get that SS spool and it's ER308 something. I looked at it too quickly yesterday when I was going through my stash.

 

[MoonRise]

Update: I did go get that SS spool and it's ER308 something. I looked at it too quickly yesterday when I was going through my stash.

Yup, 308 stainless filler is 'standard' stuff. Use it for welding 302 or 304 stainless (and some other stainless alloys too, check a 'recommended filler material' chart for specifics if interested).

Still really no need to use 308 filler when welding mild steel.

(caveat: sometimes 308 filler is used for a 'buttering' pass before putting down some hardfacing fillers. Adds a couple of percentage points of chromium into the mix and possibly lets you get a couple points harder on the hardfacing result. RTFM for specifics, if interested. Not what you are dealing with here though in trying to weld some mild steel pieces together. Just use standard mild steel filler, whether GMAW or GTAW or FCAW or SMAW. Doing it yourself, you probably won't be using SAW (Submerged Arc Welding). )

 

[Zeke]

And you're (Moonrise) just the kind of guy I was looking for when I started the thread. Thanks.

All done now, time for paint.