Mig Weld 304 Stainless Steel?

[Malicia]

Can I use a Mig to Weld an exhaust out of 304 Stainless steel?

Will one of those Ebay 100 AMP Gasless Migs do the job? (Didn't someone here buy one recently?)


Don't know much about welding other then melting stuff in yr 12 metal work and putting together a go-kart frame.

[oldcorollas]

304L is much more weldable than 304.
and get the right wire, otherwise you can have nice stainless pipe.. with welds that rust out..

i would not try using gasless on stainless, let alone an ebay jobbie
i spose you could tack them and then take to a proper welding machine to do the final weld but....

[30psi 4agte]

Yeah you can do it no prob provided you have a half decent welder.
Like OC says using stainless wire is advisable or your welds will rust.

If you are planing on having the manifold coated this mabe ofno concern.
I have used normal wire to weld stainless a few time now. I did my stainless dump with normal wire and had it coated......... I havent had any cracking or rust issues.

Using mild steel wire will give you a slightly weaker weld opposed to stainless wire, so keep that in mind.

So in summary:
I woulndt use mild wire on a exhaust manifold as they see some stress / vibration and constant temp. ...Go TIG in this instance.
I have used a mig to tack manifolds and then taken them to be tig welded

Dump pipes you can get away with mild provided it is coated to stop rusting , NOTE: paint wont work here..... It needs to be ceramic coated

[Malicia]

Looks like I'll Tack it and then find someone with a TIG to finish the job.

[The Last Streetfighter]

304L is much more weldable than 304.

You might find 304/304L. This is certified to meet the requirements of both grades.

http://www.eng-tips.com/viewthread.c...=180920&page=1

This here is also a good little read, but takes some interpretation: http://www.assda.asn.au/asp/index.asp?pgid=19262

AS4041 is Pressure Piping
AS1210 is Pressure Vessels

And a note on finishing: http://www.assda.asn.au/asp/index.asp?pgid=17977

[Toysrme]

You can fcaw stainless, but you're going to get shit for results because:
Flux-core is meant to be run in spray transfer only. Chinese cheapo's run short circuit.
fcaw = ugly, fcaw-s (co2 shielding) is very, very high quality.
You have no backpurge, or shield for the back of the weld. It will grossly contaminate the weld all the way through from the backside. The only fix for that would be a product like SolarFlux.

Can you do it, sure. Will it hold a manifold together. Not unless it's thick. Schedule-40 atleast. (0.154 inch)
Expect the welds to look like birdshit in the process.

[Jasper]

fcaw-s (co2 shielding) is very, very high quality.

Using a shielding gas containing CO2 will cause carbide precipitation around the weld, lowering the local concentration of Ni and Cr, and allowing corrosion.

[1jzracing]

contrary to what the cheap-arse advertisment says there is NO SUCH THING AS A GASSLESS MIG WELDER!!

there is flux core wire best used for positional welding but it still works best with a shield gass

those cheep welders actually work quite well for thin gauge jobs but only when used with co2 or argoshield and will weld up your exhaust a treat with a bit of practise, make sure your joins have no gaps

you will find it will be quite sensitive to the right power v's wire feed rate

[Malicia]

Great info guys,

After abit of research I came across this statement from an exhaust shop:
" Welding can be done with either a MIG or TIG. For a mig, use stainless wire and gas specially for stainless welding (AGA gas sells this under the name Stain-mix)."
(They are talking about 304)

Does this sound right, as it might be an easier option for me. If not then I will have to tack it and take it in to be welded.

[JBs]

Great info guys,

After abit of research I came across this statement from an exhaust shop:
" Welding can be done with either a MIG or TIG. For a mig, use stainless wire and gas specially for stainless welding (AGA gas sells this under the name Stain-mix)."
(They are talking about 304)

Does this sound right, as it might be an easier option for me. If not then I will have to tack it and take it in to be welded.

Yep that sounds about right, the stainshield gases BOC have from memory are an Argon/CO2/Helium mix, the catch is they only sell them in the G size cyl so I have heard of many a backyarder getting away with using a small bottle of straight Argon. But as you said may be easier to just tack it then have someone TIG the rest.
Cheers

[oldcorollas]

http://www.burnback.com.au/helppdf/gasinfo.pdf
Stainshield.. argon with 1 or 2% oxygen...

[Malicia]

Got a quoate on Stainshield D size 30 day hire $68.38

Looks like I'll go with that.

[hypo23]

just use a stick welder with stainlrss rods

[1jzracing]

just use a stick welder with stainlrss rods

..... have you ever tried welding 1.6 gauge steel with a stick welder??

stick welding stainless burnes much hotter and more molten than mild steel too, so it would be near impossable!!

stick with the MIG

[hypo23]

was taking the piss mig is the go, using a stick isnt impossible on 1.6mm a 2.5mm electrode on low amps, would be a bitch to start bit once you got going would be okish

[Steve M]

When I did mmaw on 1.6mm we used a 3mm electrode on low amps if I remember rightly, as it fills in the holes quicker. You've got to be quick though. I was told that using 2.5mm rod leaves too many holes behind. That's what my lecturer told me anyway. It worked ok so I was inclined to trust that for Mild Steel welding.

That said, I've only ever welded stainless with TIG, and that system is is the go, definately.

Tack with MIG and then TIG from there.

[Ribfeast]

We used a mild steel gasless mig for my stainless intercooler piping. Looks shit, and rusts after a few weeks. Penetrates OK though. I just buffed it shiny then sprayed it with clear coat paint to protect from rust. Works OK

[JP]

I've just tig'd up some 1.6mm wall stainless cooler pipes for a mate that tack welded them with an ARC welder and stainless rods... was a pain to fill the holes the ARC left behind. Tacking with a MIG and then getting them TIG'd would be the go.