welding stainless to mild steel

[kamaroman68]

Is it possible to mig weld 14 gauge stainless to 14 gauge regular mild steel? If so what gas would I use and I would assume I would use stainless mig wire? Is stainless going to be as strong as the same gauge mild steel? Thanks guys Chris

[Camaro Zach]

you can weld it with your standard mig wire and argon mix, just the only thing is the weld will rust and partially contaminate the stainless.

[Matt@RFR]

"Strong" is an extremely underdefined term. Being that you're using 14ga, obviously it's not structural, and if it will be coated, Zach's recommendation will be fine. And to clarify, Zach said to use your regular 75/25 mix.

If the stainless portion will not be coated and/or this weldment will be under load, ER309 wire is your choice. It is generally the best for matching both alloys as close as possible, and has ok corrosion resistance. 75/25 here too.

[kamaroman68]

Matt my plan was to somewhat duplicate the inner rocker panel of a 68 camaro and then weld a piece of 1/8 ss channel to it to create a channel fitting over the frame. When you say it won't be structural i am a little confused. I believe the originals are 16 gauge and I figured I could go with ss in a heavier gauge(14). Thanks Chris

[Matt@RFR]

Sorry, bad assumption on my part! My last job was at a structural steel shop (building rock crushing plants) and the thinnest plate they stocked was 1/4, on up to 2". :)

Yes, that would be considered structural. May I ask why you're choosing stainless? What alloy?

[kamaroman68]

Matt the reason I would like to go to ss is due to where I live. Niagara Falls, NY. I am tired of rusting metal. As I said in a previous post I purchased An art morrison frame which is due to me next week. I plan on carrying the ss theme throughout the new floorpan and firewall. I believe the original rocker was made of 16 gauge steel and I figured going to 14 gauge ss would add strength. If you don't mind could you recomend a specific good grade of ss that you yourself would use? If you get a moment could you look at my previous post and see what you think about body mounts. Thanks Chris

[Matt@RFR]

You're definetely looking at using 304. It's the most ductile of the two alloys that are easily found at your local metal supply, and should do just fine in your environment. Again, just keep in mind that wherever it gets welded to mild steel, the weld will have its corrosion resistance compromised, however 309 filler does an ok job at fighting that, and still has decent as-welded properties and dilution on the mild steel side of the weld.

[kamaroman68]

Matt is 304 expensive? Finding metal around here is like finding a needle in a haystack. I'm hoping that the local fabrication shop can find some of this. Thanks a ton. Chris

[Matt@RFR]

304 will be the least expensive of any stainless, and you can figure on atleast twice the price of cold rolled mild steel sheet. So yes, it's expensive. :)

[kamaroman68]

Matt, So do you think I am crazy or would this be somewhat worthwhile? Thanks Chris

[Matt@RFR]

My personal opinion is that stainless is unnecessary, and to just use mild steel with some good corrosion resistance coatings. However, I'm in California and don't have to deal with the same conditions as you.

Mild steel will be much easier to work with.

[airrj1]

Hey Chris,

I am just south of you in South Wales. The only place that I can suggest that you try is General Welding in Elma, NY. They are just off of Rt. 400. I have used them many times for material. Never SS, but I would suspect that they could get it. If you find somewhere else local I would be interested to see what you find.

Good Luck.