Welding Stainless?

Does stainless need to be TIG welded?

Stainless can be welded using a mig with normal steel wire and argon/CO2 mix.

Notice I said can, I'm sure the bond is less than awesome and of course you're giving up rust resistance in the process.

I routinely weld bits of old german stainless exhaust to new bits of aluminized exhaust with no appreciable difficulty. I'm sure someone with a proper welding backround will step in with information on why this is a bad idea.

MIG + Stainless Wire + Tri-Mix = Stainless welding

You can use steel wire, but WHY? Don't bother trying to weld stainless on the cheap with a C25 mild steel mixture. I've tried and it will give you a subpar result.

You can mig stainless just fine. I use stainless wire, the mix isn't really that important, C25, tri mix etc. The best results are with 100% Argon or a Argon/Helium mix.
What IS more important is the back side of the weld, you should use either a shielding gas on the backside or solar flux B which is a powder you mix with rubbing alcohol and coat the back of the weld to prevent oxygen contamination. Without the coating you will get black crystals or sugar in the weld on the backside that makes the weld weak.

Tig welding is really the best way to weld stainless, but mig welding it is very doable as well.

Chris Rummel

Thanks.

This is a small, simple job. I'm just adding a stainless 02 sensor bung into a stainless exhaust system. I have a MIG, but for a job this size, it's not worth buying a spool of a stainless wire and another bottle of gas that I'll never use again. I'll just find someone with a TIG and pay them to do it.

This thread reminds me, I have to get a new spool of stainless wire, the last one I had was almost new and the plastic end of the spool came off, spilling all my stainless mig wire onto the floor in a tangled mess. Of course this happend on 9pm on a Friday night. My local Home despot carries stainless mig wire, but I pulled up to the entrance just as they were closing the doors! I yelled berkeley and had to go home and cut a section out of the worlds most expensive slinky to feed through the mig for the little job I had to do.

Chris Rummel

The answer is no. I arc weld SS all the time, with inexpensive SS rods.

I have had zero issues welding stainless to mild or stainless to stainless using regular old ER-70S6 (? something like that) MIG wire. Even the stuff from Harbor Freight that runs $40 for a huge spool.

I just did it yesterday in fact - welded a new stainless converter on to my old stainless front pipe, and then to a new section of mild pipe onto an old rusty section of mild pipe. No problems, other than trying to mate a 1 3/4" converter onto the 1 5/8" front pipe, which was curved. (Don't worry GRMers, the teeny tiny pipes aren't a restriction - the single outlet VW exhaust manifold takes care of that job)

Only concern is to run 75/25, but then that seems to give best results for me no matter what kind of steel I'm welding.

I use 308 wire and straight Argon in my HF MIG welder. I use the straight Argon so I can do aluminum if I have to without buying another bottle. On heavy stuff, like 1/8" and up, I use AC SMAW (stick) with stainless rods.

Reviving from the dead:

What is the verdict here - can I attach a stainless magnaflow Y pipe to a 16ga aluminized steel pipe with regular steel wire and mix 3 (75% Argon 25% C02) mix?

I am not concerned about rust - just that it seals (because it is before the 02) and stays put. It seems like from reading above the answer is yes even though it is technically "wrong".

Should be able to. I repaired the SS exhaust on my van with regular steel flux core wire and no gas three years ago. Looks weren't important, it just needed to stay together. It did.

It should be fine. I'd grind off the aluminized coating first.

MIG? TIG? We do it all at hose world.

Pete... I am not normally the kind of guy to make mention... but damn. That is a huge hose you have there.

THAT'S the size flex pipe i needed! Ordering now!

Dr. Hess wrote: It should be fine. I'd grind off the aluminized coating first.

Muriatic acid will remove the aluminized coating w/o grinding and thinning the metal. For pipes off the car I pour acid in small plastic pan and dip pipe end (about 1/2"). When bubbling is done rinse pipe w/ water and just wire brush. On the car is trickier but I brush it on... vewry, vewry carefully.

Acid will also remove cadmium, zinc, galvanized coatings and rust. Try a test w/ a few cad plated bolts in acid, it'll remove the plating w/o grinding at all and welds so much better.

Don't breathe the fumes and wear PPE.

I work for a food processing/packaging plant where anything made of metal has to be SS316. The welders the maint fabbers use have the tungsten electrode and they hand feed SS welding wire. I forget the name of this type of weld, but I know what the process is anyway. I started training for the maint dept when they made cutbacks to that dept payroll.

Giant Purple Snorklewacker wrote: Pete..that is a huge hose you have there.

This is a geothermal heating/cooling system being installed at Ball State University in Muncie, Indiana. These are increasers that go on the pumps - 20"ID pipe size x 18"ID. They are designed to help stop transmitting pump vibration.

This is the largest flex connector we have made before. A huge feather in our cap. My shop was aggravated since these jammed up the normal 2"ID production stuff.

http://cms.bsu.edu/About/Geothermal.aspx

Yes you can weld stainless with regular wire and gas but it will crack and break a lot faster than if you use the right wire. My sugestion would be use a 3/32 304 stainless welding rod and small buzz box at about 60 amps. You might be able to find it at your local hardware store or any welding shop will carry a small of about 10 rods box for about 10 bucks. Just my 2 cents