Stainless welding using cheap MIG wire feed

[GSLENK]

I have this:
Flux Wire Welder - 90 Amp

I know jack and sh!t about welding. Am I creating a potential corrosive reaction between mig (intended for mild steel) and welding 2 stainless pieces together?

Can paint slow the decay process if it is significant?

I know it the wrong way. I want to TIG sooo bad, but I dont have $$$$.

 

[Raph]

Youve answered the question yourself.

Ultimatley,youll have to weld it again..depends on the application and how long you want it to last.

what are you welding up?

 

[GSLENK]

down pipe electric cutout. could I buy SS wire for the welder if such a thing exists?

Or just buy a can of argon (or whatever gas)?

I think this will be the only time I ever weld stainless.

 

[Raph]

Then mark where the cut out goes,remove pipe and take it to a shop?

 

[GalantVR41062]

You can mig weld stainless steel. I would never try with flux core wire. 304SS or mild steel works, only solid core wire with inert gas 75%Co2 25% argon. Set the welder up for less heat then mild steel welding a little slower wire speed. TIG is the ideal method for SS welding.

 

[knochgoon24]

I heard using 75/25 isn't the best for SS. Something about it pulling too much carbon from the CO2 into the weld and ruining the SS properties. If the problem isn't that big, it will save me from buying a tank of 100% Ar.

 

[GalantVR41062]

If I use a wire feed on stainless its only to gaft some cheaper exhaust back together and the chunk of SS is on hand and right length. Or if I do exhaust hangers on a SS muffler that is MIG welded together from the factory. Use the 75/25 it will stick it together.

~John

 

[brownfinger]

I have 309L SS wire that I use in my MIG with 25/75 star-gas (argon/CO2). On nice stuff, like 304 SS Thermal exhausts, I make tack-welds with my MIG, and take the piece to a shop to be TIG-ed. On cheap crap, like a 409 SS high-flow cat with junk chinese eBay flanges, I just MIG it all around. It works fine. SS MIG wire isn't hard to find, and the guy at my local welding shop said they don't bother switching gases when they MIG stainless.

 

[GSLENK]

So if I really have to do it (not bring it into a shop) then the way to go would be:

SS wire, and 75/25 argon/co2 gas.

Thanks all. Ill probably just end up taking it to a shop... F@#$@#$%^^ here goes another $100. I might just have to find a TIG machine and call it a day. 5 more little projects and it would have paid for itself already

Thanks for seriously answering a relatively stupid question. I just couldnt find any info other that "aaahhh it cant be done" when i just mig'd 2 SS scraps together.

 

[CrawlinZX14]

First your welder is not a mig even. Mig has the ability to feed the shielding gas thru the unit. I have a very similar setup with my lincoln welder. They do not have the needed parts to run mig. Yours is simply for flux cored wire. I dont think you can really just spray the shielding gasses on the weld while feeding solid cored wire thru it.

 

[GSLENK]

great thats the answer i was looking for. thanks.

 

[danl]

I heard using 75/25 isn't the best for SS. Something about it pulling too much carbon from the CO2 into the weld and ruining the SS properties. If the problem isn't that big, it will save me from buying a tank of 100% Ar.

I've gotten pretty good at MIG welding my 304 series charge pipes. The 75/25 will not work however even with the proper SS wire. You will get WAY too much splatter, but for an exhaust it won't matter. You need the trimix gas, helium, argon, and CO2 to make it nice. Depending on the thickness you will have to alter your welding technique. I was doing some pretty thin stuff, 18 gauge which was thinner on the outside of the mandrel bend. Usually I will use a back and fourth "C" method when doing thick mild steel like a roll cage or even exhaust flanges. However when butting up two pipes you may need to use the pulse method. Stainless steel is neat in that it flows good when heated. When you get it right you will see the two pieces melt together like you are soldering a joint.

Now, since this is only exhaust I would just use your normal mild steel wire and 75/25 gas or your flux core wire. It will look like hell but hey, its an exhaust part, nobody will see it.

 

[GSLENK]

Now, since this is only exhaust I would just use your normal mild steel wire and 75/25 gas or your flux core wire. It will look like hell but hey, its an exhaust part, nobody will see it.

So you can flux core it? I really dont care if its ugly, as long as its not going to react terribly over time. (I can deal with fighting rust, its called spray paint) If cosmetics are the only ill effect, then Ill try it. If its going to react, and corrode and die in 5 years Id rather not. If its gonna die in a year then Hells no I wont.

 

[Sirnixalot]

i have done it.

I had to bastardize a Megan stainless downpipe for use with my custom Evo X turbo conversion. I welded a mild steel V band ring to either end of the stainless down pipe with mild steel flux core.

Not the best pic of the weld but it hasn't fallen off yet

You must be logged in to view this image or video.

 

[GSLENK]

Ok im sold. Im gonna try it. Just wait for the post where I say "Stupid F@%$@# $100 hack downpipe just sh!t out my new $200 dmh cutout 5 miles ago" I guess im not at much of a loss if it fails... 20 for the SS "y" cutout, and $60 for the DP, $80 lesson to gamble with $80+ worth of welding....

 

[99gst_racer]

I welded my 304 SS side exit exhaust with a MIG and mild wire a few years ago, and it turned out great. I didn't own a TIG at the time, so it was my only option. I was using the 75/25 gas mix. I ran it for 2 years with no problems and sold it to someone who is still running it. I had painted over the welded areas with high temp paint and then wrapped it with header wrap. Never had any corrosion issues.

 

[GSLENK]

Did you fill the pipe with gas (to back fill the weld)? or did you just use the welder as is (wire feed + gas)?

I guess Ill have to at least upgrade to a gas mig welder, as mine doesnt have a gas hook-up.

 

[Gamble97]

I heard using 75/25 isn't the best for SS. Something about it pulling too much carbon from the CO2 into the weld and ruining the SS properties. If the problem isn't that big, it will save me from buying a tank of 100% Ar.

He has a flux welder so the shielding is built into the wire and uses no gas.
Tri mix for SS.

 

[99gst_racer]

Did you fill the pipe with gas (to back fill the weld)? or did you just use the welder as is (wire feed + gas)?

I guess Ill have to at least upgrade to a gas mig welder, as mine doesnt have a gas hook-up.

Nope, no backpurging.

Yeah, you'll definitely want to use gas. My welder works both ways, and I tried gasless one time and hated it. It's a night and day difference between the two.

 

[knochgoon24]

He has a flux welder so the shielding is built into the wire and uses no gas.
Tri mix for SS.

I don't use enough to keep more than a 20 CF bottle on hand. And the local shop won't fill small bottles with Trimix. However, I can get Ar.

 

[Gamble97]

Nope, no backpurging.

Yeah, you'll definitely want to use gas. My welder works both ways, and I tried gasless one time and hated it. It's a night and day difference between the two.

I've heard people use flux wire WITH gas and they have good results. Never tried it though.