Welding stainless to mild steel??

[8man]

I picked up a stainless 3rd brake light for my 54 Chevy truck cab. The instructions said "can be welded in place". I would like to weld it but have never tried welding stainless and don't know if it is a different wire or process or what.

I have a Lincoln 140 MIG that has worked well on the mild steel replacing body panels and such, but need some advice here. I have some easy grind wire that I've been using on the mild steel.

Thanks.

 

[dr_clyde]

The correct wire is 309, proper gas for mig would be a tri mix of argon, co2 and helium.

 

[Marctrees]

I have minimal welding experience..

I don't know all the correct lingo...

A few years ago I made some BBQ grates.. welded a bunch of 3/16 stainless rods across a regular steel frame.

Used my regular wire feed welder, common wire, gas shielded w the standard stuff.

All the same stuff I used to build the entire steel BBQ... just a lower setting on the machine.

Worked great, still good.

Only thing I will add is... possibly one would use something different if appearance was critical, but for my purpose, was more than fine.

Marc

 

[marinusdees]

You can weld stainless to mild steel. Use stainless wire and Argon gas. Or, mild steel and ar-co2 mix.

 

[Marctrees]

I guess the main point I wanted to make was I used the samw wire, the same gas as "normal" for regular steel, and it worked out totally fine... nice good looking strong welds.

I did not go out and buy anything different.

I had no idea how well it would work, so I just tried it first w scrap.

Worked great, so then I did the full project.

Just my minimal experience, not at all a "Welder".

Marc

 

[sberry]

For a common bracket you can use steel.

 

[wrenchguy]

54 bolt truck cab, 3rd brake light???? why?

 

[MoonRise]

As dr. clyde wrote/said, the 'correct' filler metal alloy to use when welding (most) stainless steels to (most) non-stainless steels is 309.

And the shielding gas to use is tri-mix argon/helium/CO2 blend (for short-circuit transfer mode GMAW, which would be what the PM140 can do and what you would usually use on sheet metal GMAW anyway).

Straight argon and GMAW (AKA MIG)? That's for aluminum GMAW only usually (sometimes for GMAW using bronze or such). Never for GMAW on steel (either plain steel or stainless steel ).

 

[Lwel9226]

You can weld stainless to mild steel. Use stainless wire and Argon gas. Or, mild steel and ar-co2 mix.

This will work very well..... Just use what you already have...

LynnW

 

[sberry]

I had a job come in a while back. It was a skin on a semi bumper. They figured cause it was stainless is was a big deal I guess. All the **** was beat up already and took some welds on the back, couldn't even see them., it got lo hy.
I will agree there is a correct way when there is a defined procedure or compelling reason, to tack a bracket on no one can really see, non critical it doesn't matter much.
I still have part of a box of 309, havnt used it in a while.

 

[laser3kw]

I welded a 304 stainless cat back system using regular er70s mig wire. It held up well for the last 8 years in rust belt weather. Still holding when I sold the truck.

 

[Marctrees]

Certainly, with my method, the weld will rust along w the regular steel.

NOT NOT be non rust as the stainless rods I used.

I would assume, with the different wire specified above, and POSSIBLY different Gas, the weld will NOT rust as the surrounding regular steel.

But w what I did, BBQ grates, even though the welds rusted along w the frame mild steel, it still alllll worked out long term.

That's all.

Marc

 

[sstec]

We tig with 309 rod and 98/2 argon/C02, no trimix.
Works fine for US.
sstec

 

[dr_clyde]

We tig with 309 rod and 98/2 argon/C02, no trimix.
Works fine for US.
sstec

TIG would be pure argon normally. Tri-mix is for mig.

 

[Marctrees]

Thing is, even though maybe the posted combos are a better quality weld, like for production, I think OP asked , in my words... "Can I do this one time job w what I got in house".

Marc

 

[dr_clyde]

Thing is, even though maybe the posted combos are a better quality weld, like for production, I think OP asked , in my words... "Can I do this one time job w what I got in house".

Marc

Sure you can weld it in with a coat hanger and it'll probably be fine.

He also asked about "a different wire or process or what". Telling him the proper way probably falls under the "or what".

 

[rsanter]

You can weld it with whatever regular wire you have for steel, but it will deplete the nickel and some other elements from the weld zone and you will,essentially not have stainless steel in that area anymore.
If you are going to paint it, then no matter.
If you plan to leave it stainless and paint up to the bracket then you will want to use the proper stainless wire and ideally a TIG

 

[8man]

Thanks guys. I did ask two questions.

First, it will be painted as it is going on my truck, it's a 3rd brake light. So not having stainless is fine, and being able to weld with my EZ grind wire makes it easy to keep moving forward.

Second I did want to know the correct way to weld stainless. I got that information as well. I'm not going to weld this to keep the stainless attributes, but I may want to weld stainless in the future, so knowing is being prepared.

As for the question about "why a 3rd brake light on a 54 Chevy truck", well I live in a college town with 60,000 plus students all driving and texting and I want to put out as much brake light as I can. I'm putting LEDs in the bed rolls, a license plate ring with LEDs on it and this 3rd brake light to go along with LED brake lights and turns. I'm just trying to protect my truck while keeping it looking as stock as possible on the outside. That is why the 3rd brake light will be cut and welded into the cab, so if fits the lines of the cab.

Thanks all.