Anyone ever MIG stainless exhaust pipe?

[z28snksknr]

I have a rather expensive (to me) Corsa exhaust system on my Z-28 and the inlet to the muffler has a broken weld between the muffler case and the inlet stub. It's 304L Stainless pipe / muffler.

I only have standard 0.030 wire and Stargon shielding gas. Any suggestions on whether I can get this done at home with minimal investment (buying a small wire spool or just using what I have) vs. taking it to a muffler shop and hope they actually use the right stuff to weld it up?

Thanks in advance!

 

[drive em]

You can weld it with regular MIG wire, but a better job would be to get a small roll of stainless steel wire and use that.

 

[toxicz28]

Stainless wire with a tri-mix gas. $15 for the wire, not sure about the gas.

 

[pirana]

Stainless wire with a tri-mix gas. $15 for the wire, not sure about the gas.

what he said!

 

[z28snksknr]

Stainless wire with a tri-mix gas. $15 for the wire, not sure about the gas.

Trimix being argon, CO2, and helium?

 

[APEowner]

Whenever I need to use a bottled gas that I don't usually use my dealer loans me the bottle and just charges me for the contents of a full tank. It's still probably cheaper to just find someone to make the one weld for you.

 

[SM Racing]

You should be using straight argon with Stainless wire, it is cheaper and welds fine. You may want to just tack it with what you have and carry it to a welder and have him TIG it. That way it will come out nice. Make sure he back purges the tubing.

 

[crewchief888]

i fabricated a 2 into 1 stainless exhaust for my iron head with stainless wire and CO2/argon mix and it came out fine.

FWIW my local welding supply told me the mix gas would be fine for what i was doing, seems they suggested straight CO2 for anything being in contact with food.

 

[toxicz28]

Trimix being argon, CO2, and helium?

Yes

You should be using straight argon with Stainless wire, ......

Only for tig. Straight argon is for mig welding aluminum.

 

[z28snksknr]

i fabricated a 2 into 1 stainless exhaust for my iron head with stainless wire and CO2/argon mix and it came out fine.

FWIW my local welding supply told me the mix gas would be fine for what i was doing, seems they suggested straight CO2 for anything being in contact with food.

Can I ask what stainless wire you used? Lincoln's site guides me to wires that are only sold in 300lb spools apparently.

 

[AussieDan]

You can use 308L wire with 75%Argon/25%CO2 for joining 304L stainless, your local welding supplier should have 2lb spools available.

 

[nissan_crawler]

Will a band clamp work? I used them on the titan, since all the shops around here insisted on welding stainless systems with regular steel wire. Hacks.

 

[z28snksknr]

Will a band clamp work? I used them on the titan, since all the shops around here insisted on welding stainless systems with regular steel wire. Hacks.

That's what I was afraid of - calling some shop and asking them if they weld stainless and then they use standard wire. That and I've never seen a nice weld from a muffler shop.

The joint is on the muffler casing itself and the inlet pipe, so no clamping.

I'll look around and try to find some 308L wire. Thanks for the help guys!

 

[AussieDan]

If you have trouble finding 308L, in a pinch 309L wire will work also. It's meant for joining stainless to mild steel and isn't quite as strong as 308L, but for an exhaust it'll be more than adequate and shouldn't rust out like mild steel wire.

I just welded up the exhaust on my car with 309L wire and 75/25 Ar/CO2, it's not the prettiest thing in the world (made out of various used pieces and sprayed with VHT flame-proof) but so far it's getting the job done.

 

[Damon L.]

I picked up a 2lb spool of 308L at Fleet Farm to weld some 18 ga or so SS sheet metal in the FILs barn. Worked OK with Stargon mix gas, albeit a bit messy. The wire brush cleaned them up nicely though.

 

[eak1999]

I bought a 2003 pickup and found a good example of crappy welding with regular steel wire. Just thought people should see what that steel wire looks like when the exhaust is 10 years old. All of the welds were severely rusted and some had rusted all the way through until the pipes came apart. This was a nice Flowmaster aftermarket exhaust. It probably would have lasted another 10 years if it had been welded with stainless wire.

I installed a new Dynamax exhaust to replace this. After seeing what happened to the old exhaust, I decided against welding the new exhaust. I ended up using the newer style clamps that came with the Dynamax kit (see example photo). These clamps work much better than the cheap clamps at the auto store and they actually seal the exhaust - no audible leaks. If I have trouble with the clamps in the future, I will have someone weld it with stainless wire - I will never allow steel wire on a good exhaust system again.

 

[hackwelder]

I did it on my Birkin, the system was a mix of SS and regular steel, installed a new muffler and resonator and did all the welding with regular 0.030 MIG wire and CO2...held up OK for the five years I owned the car, no leaks, breaks, etc.

 

[bad_idea]

When welding stainless, wear a respirator. Stainless puts off Chrome Six, google it, it's bad mkay.

 

[shawhite]

Typically u dont use c25 with stainless. It will leave a bead that will rust like mild steel. You should definitely use a tri-mix or pay a welding shop to weld the stainless.

 

[steel 35]

Here is the last one I did, dual 3". Oh its the dreaded steel mig, I have experimented with stainless wire and the only thing I haven't tried is the tri mix? This was done about 9 years ago, and recently dropped for other modifications still no leaks.

 

[RogueFab]

I have done it a few times. Argon/CO2 blend and standard solid MIG wire. On exhaust it works fine. Don't do it without the right wire on structural work

 

[bsaint]

Trimix is wicked expensive. Its not worth the investment for a couple beads of weld. I was told by the store you can run 95/5 as a cheaper alternative but only comes in big tanks.

 

[laser3kw]

I had to cut and shorten my SS Magnaflow cat back. I used regular S-7 steel mig wire and C25 and stitched the joint. That was 6 years ago, no problems - yet. I know it will rust through eventually.

 

[paranoid56]

If you have trouble finding 308L, in a pinch 309L wire will work also. It's meant for joining stainless to mild steel and isn't quite as strong as 308L, but for an exhaust it'll be more than adequate and shouldn't rust out like mild steel wire.

I just welded up the exhaust on my car with 309L wire and 75/25 Ar/CO2, it's not the prettiest thing in the world (made out of various used pieces and sprayed with VHT flame-proof) but so far it's getting the job done.

i know this is old, but nice looking exhaust hangers there

 

[AussieDan]

Yes indeed They work great and made me smile any time I was under the car!

 

[goodinblack]

Please help

I have a Lincoln electric pro mig welder.

I need to weld in a MagnaFlow Stainless to the stock steel pipe.

What gas and what wire should I use for this?

Thank you

 

[steel 35]

Run what ya brung!

 

[laser3kw]

I need to weld in a MagnaFlow Stainless to the stock steel pipe.

the stock steel pipe must be near rust free to do any welding to it.
if you can grind or sand it to "shiny" you might get a weld to stick.
standard E70S6 and C25 gas will give good results if the material is prepped right.

 

[welder4956]

The problem with using carbon steel wire (ER70S-2 thru ER70S-7) is that carbon steel expands at a slower rate than stainless steel when heated. The difference in thermal expansion creates a high enough stress to cause the carbon steel weld to crack eventually. And the final weld metal composition after mixing with the stainless steel is going to make the microstructure be martensite, which will be brittle. Then to make it worse from a corrosion standpoint, the small surface area of the carbon steel compared to a much larger surface area of stainless steel will cause a galvanic couple. The good side is that exhaust temps will usually be high enough to evaporate off any moisture from the road (rain or snow), but if there is condensation inside the exhaust on the welds, there will be corrosion. The welds will probably last a few years, but will eventually crack. So, if you are just trying to get by for a short time, the carbon steel wire will work. But if you are fabricating a custom exhaust and want it to last a long time and appearance is also important, then stainless wire is advisable. As far as shielding gases, tri-mix is not mandatory. A 98% argon-2%oxygen mixture will work fine and is a common gas mixture available at the local welding supply houses.

Edit: I should also add that not all "stainless steel" exhaust piping is equal. Some exhaust materials are Type 304 stainless and some are Type 409. The OEMs tend to use 409. The 409 is more tolerant of using carbon steel weld wire and 75/25 gas.

 

[Zengineer]

Rather than go to a muffler shop, hit up a custom/racing shop in your area and ask them. They will have the equipment you need to fix it right, and likely won't cost you any more than the muffler shop would charge you...