Mig welding, floor pans, no gas?

"Grindintosecond" (Grindintosecond)
04/16/2014 at 12:14 • Filed to: minifix

Do I really need the gas? I see talk of "It makes yer welds purty" but I will be grinding the lumps away anyway, then protect spraying over it. So do I really need to get a tank of gas? What wire would be best for floor pans without gas use if this is the case?

DISCUSSION (21)

Party-vi > Grindintosecond
04/16/2014 at 12:20

Using the shielding gas prevents weld impurities and creates a stronger weld that resists oxidation better, or at least that's what I've been taught by my dad.

I'm sure BrownDogWelding would know specifics.

puddler > Grindintosecond
04/16/2014 at 12:20

the gas protects the weld from impurities, more for structural welds. but they sell flux-core wire for use without gas. don't forget the wirebrush.

CAR_IS_MI > Grindintosecond
04/16/2014 at 12:21

So do I really need to get a tank of gas?

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The gas is shielding, it prevents oxygen from getting into the weld and making your weld weak and brittle. Unless you are using a gasless MIG with the proper wire (for gasless).

RamblinRover Luxury-Yacht > Grindintosecond
04/16/2014 at 12:21

You absolutely need gas for that, unless you're using flux-core wire. Not only does it get your tips way too hot without (bad for the welder overall), but the weld will be porous all the way through, aka "HERE, RUST! HERE, BOY!" Not only that, but without oxygen being occluded, you will literally burn away more of the parent metal you're trying to stick to. Also also, you'll be clogging up your gas shield with spatter and burned nasty welding without, so it'll be a mess to clean when you *do* need gas.

Get. Gas.

For Sweden > Grindintosecond
04/16/2014 at 12:21

Welding gas is used to keep air contaminants out. Contaminants make the weld weaker, not just uglier. If you don't want to buy a tank of argon, use an arc welder.

Jake, Yes, wearing khakis > Grindintosecond
04/16/2014 at 12:21

When me and my buddy did the "floor pans" in his 91 z28 we didn't use gas with our mig welder. But take into account that these were just flat ugly floors on a $500 "racecar" without racecar safety features. I say if your covering it up or cleaning it up anyway screw it, no gas. Also, we used liquid nails to seal around the pans lol

Grindintosecond > Party-vi
04/16/2014 at 12:25

That's sound theory behind that. Sounds good to me. I'll be spot welding all over the plae till it's a solid seam to prevent warping of the metal. This is just floors of a unibody OG mini. I guess I should go find a gas bottle for this, i'm just a natural cheapskate trying not to spend money, it's always in short supply for me. For floors, I didn't know if gas was really THAT important or not.....it's some pretty large sections.

Grindintosecond > RamblinRover Luxury-Yacht
04/16/2014 at 12:28

flux-core.....ill use that. :)

Seriously i do hear what you're saying. Are there any cons to using the flux-core over normal + gas?

Biased Plies > Grindintosecond
04/16/2014 at 12:28

You could always get flux-core wire to avoid the need for gas.

RamblinRover Luxury-Yacht > Party-vi
04/16/2014 at 12:30

Right on both counts - if you've ever seen a non-gassed weld, it looks like metal foam. Burning steel releasing little pockets of hardening CO2 which then solidify into little bubbles with rust already inside, with cracks at the weld interface - it's no joke.

Having done small point welds without gas, and having tried to seam small pieces when out of gas, I can assure all and sundry that welding without is literally harder due to metal burning away, being harder to stick, not even counting the many disadvantages of the end product.

Nonster > Grindintosecond
04/16/2014 at 12:31

Without the shielding gas the weld will be very weak. Depending on what welder you have, you could possibly convert it to run with flux-cored wire. This wire produces the shielding gas as its burned. My first welder was a flux-core, but I converted it to run as a regular mig with shielding gas.

Just get a tank of Argon or Argon/CO2 mix you'll have much better results

BiTurbo228 - Dr Frankenstein of Spitfires > Grindintosecond
04/16/2014 at 12:31

I tihnk you might need breathing masks for flux-core wire. Not sure whether that's just with separate flux, but it's nasty stuff to inhale.

Frank Grimes > Grindintosecond
04/16/2014 at 12:33

crap load more sparks and fumes. just get the gas.

Party-vi > Grindintosecond
04/16/2014 at 12:34

I've always run gas for spot welds. Also, don't forget to seam seal it!

BiTurbo228 - Dr Frankenstein of Spitfires > Grindintosecond
04/16/2014 at 12:34

To be perfectly honest, a tank of gas will probably be the cheaper option if you're doing more than a little bit of welding. I don't know about the price of flux-core wire, but the bottle of Argon we've got has lasted for bloody ages.

RamblinRover Luxury-Yacht > Grindintosecond
04/16/2014 at 12:38

As BiTurbo and FG said already, sparks and fumes, and hotter than gas, so harder to get good welds on thin metal with.

Merkin Muffley > Grindintosecond
04/16/2014 at 13:01

don't cheap out on the welding. Imagine if you were paying someone else to do the work, and you heard them ask the same question you did. You'd be livid.

tromoly > Grindintosecond
04/16/2014 at 13:10

Using gas allows the weld to penetrate easier, the only way to get around not using gas is to crank up the amperage which puts lots of heat in the part, possibly causing warping, and is especially bad on sheet metal.

You can tell a Finn but you can't tell him much > Grindintosecond
04/16/2014 at 13:14

Flux core is going to have slag that you need to clean up and will probably give a lot more spatter than you would get by using solid wire and gas. Using solid wire + gas will give a strong, nice looking weld with minimal clean up necessary before painting.

sammytaylojr > Grindintosecond
04/16/2014 at 14:33

If you want to waste a bunch of money, save a little bit by skipping on the bottle.

zdzichu > Grindintosecond
02/12/2018 at 08:53

welding MAG/MIG with no shielding gas:

-your bead will be one big bloob of porosity

-welding with no gas will not provide enough temperature and adequate penetration

-will heat up your torch and most likely stop the wire feed.

If you cant afford ar/co2 mix use co2 fire extinguisher or pub gas. You can also buy fluxed wire. If you are still not convinced to buy gas just buy a stick welder- little inverter will cost you 50-60£ from ebay or buy from lidl,aldi etc. pack of rods is 4-5£ cheap as chips.