What do I need to MIG weld stainless steel, i.e. wire, gas etc?

My Civic exhaust has decided to die a death, and unfortunately my choice of replacment is severely limited (MB6 chassis, same as Rover 400). I can get a chavvy aftermarket performance system for around £280 with a tail pipe the size of a dustbin, a nicely made Supersprint mild steel performance system for a mere £365!!!!, or a very crappy standard aftermarket one for £175. The genuine Honda one is nearly £300.

However, the design of all the earlier Civic exhausts is very simmilar, so I'm considering getting a decent stainless system for a 4 door saloon and cutting and shutting it to fit.

you'll need:
pure argon gas, can use mix but co2 makes it splatter lots and darkens, stainless wire you also want to put a piece of the parent metal around the earth clamp or it will colour the stainless aswell....You'll prob need quite a high power setting as ss melts hotter than ms.....Hope that helps...Oli.

For an exhaust, just get a small roll of stainless wire (0.6mm), your normal TC gas will do the job

tig welding is a lot neater but harder to do,mig welding stainless using mild steel wire and helium gas gives a neat weld but will rust, stainless wire with helishield gas will not rust but not quite as neat,ps can you help with my castor angle query nice one mate

If stuck use normal mild steel wire...RH do

Cheers guys.

I have a cylinder of argon/CO2 mix, bit relucatant to buy a cyclinder of pure argon just for one job (bad experience with thos small cyinders, they seem to leak slightly if used once and then unscrewed, and months later you come back to empty bottle!).

and for TIG pure Argon..


use stainless wire else you can do the jobvery often...

i think you need low setting because its thin material/often..

Tks

Hi,same from me,argoshield mix will weld fine for the job you are doing.
I welded my Indy stainless system where it bends into the silencer as I had to alter the angle. I just buffed it up to get the dark oxide off and it looks fine on the outside of the car,so yours will be ok underneath.

The co2 in the gas introduces carbon into the weld and it will eventually rust even though it's stainless, but it will probably outlast the rest of the car.

If you want to do it right and have a nice stainless weld which will not darken or rust get yourself a couple of little bottles of Argon and the stainlesss wire. It's worth a bit more for the saitisfaction of doing right.....As others have said you can do with ordinary wire and argo-shield but there are a few problems with this:
Stainless Steel has a higher melting point than mild steel so you will find that penetration is nowhere near so good. And as mentioned obviously using mild steel wire will mean that your weld will rust and generally look crap next to all that nice stainless stuff! Do remember to put some stainless materisl between the earth clamp and the exhaust though or you'll make a mess of it's finish. I would only ever do what others are suggesting if it's a realy tiny amount eg 1 tack or I was too tight to buy the right stuff....on something like a brand new exhaust its just not worth it! Do it right the first time and you'll be glad u did in the long-term trust me! Rant over....Oli.

I welded my stainless exhaust system with 1.5mm arc rods, they were Eutectic 680s for dissimiliar metals. If you can arc weld then it is another option and can be done fairly neatly with some practice.
Paul.

I have a completely different experience than others suggest. I used really thin stainless wire (.03” IIRC) and 80% argon, 20% CO2. I’m no professional welder, but the stainless pieces I’ve welded get great penetration at the lower heat levels. I just completed my stainless exhaust. Because it can be seen easily, I tacked using MIG and took it to a TIG guy for complete welding. Even using MIG, I got no spatter and nice looking welded, but MIG welds nonetheless.

For your exhaust, assuming no one will ever see the welds, I would personally have no issue welding it. Just my opinion.

--Chris

I have done quite a bit of stainless DIY mig work and you DO NOT want pure Argon - It does not work with mig - You will get a neat enough good weld with Argoshield light - but the best stuff to use is Helishield an Helium mix.

As I use Stainless and Mild quite often I just use the Argoshield light and put up with the slightly dirty welds - but the strength of the weld is very good.

The biggest problem with welding thin-ish stainless is that you can only get .8 welding wire so the current has to be on the high side.

Hope that helps

Andrew