Welding Stainless to mild steel?

[wyorunner]

Not sure where to post this so I figured here would be best, if it needs to be moved please do so.

I need to replace some sheet metal in a cab floor of a truck. I have ten or so sheets of 4’x4’ stainless that I paid nothing for needing to be used or discarded.

It seems that combining stainless to mild steel is doable and done plenty. But as only a novice welder I’m not exactly sure what need a to be done to ensure long lasting welds.

Stainless steel wire and C25 gas and run it?

I know there’s a great wealth of metal melting knowledge here and was hoping y’all might be able to help me save a little money by not having to buy more steel.

Thanks in advance.

[JR]

No expert, but just use your Mig as setup for mild steel.

75/25 mix should be fine.

[stlaser]

Unless you have stainless wire and the right mix handy don’t bother spending the extra for it. The original is mild so it’s only as strong as that....

Burn it in hot otherwise, shouldn’t be any issues. Make sure both are clean prior to weld.

[KensAuto]

I would add that stainless wire will burn through mild sheetmetal faster.  Iirc I couldn't find smaller than .035 stainless wire locally.
Just use .023 mild wire and it'll work fine as long as the stainless sheet isn't much thicker than the body metal.

[wyorunner]

I would add that stainless wire will burn through mild sheetmetal faster.  Iirc I couldn't find smaller than .035 stainless wire locally.
Just use .023 mild wire and it'll work fine as long as the stainless sheet isn't much thicker than the body metal.

I think the stainless sheets are either same thickness or just a hair over.

Ok just measured, stainless is .1005 so approximately 12ga... where as the body is 14 ish.

Ken, where do you get your metal working supplies up there? Do you use phoenix welding supply?

[KensAuto]

This place is a man's candy store,  on 48th street.
I've also used Davis Salvage.  Not as fancy but cheaper...north side of the airport.
No places in Tucson?

https://www.industrialmetalsupply.com/index.php

[KensAuto]

Sorry I misunderstood your question. We have a couple welding stores here in town...Browns and Praxair
..but Industrial also has some supplies,  but no gas.

[wyorunner]

We have Phoenix welding supply and then another metal shop. Tucson has a great shop for metal supplies but no gas at that one. I was just curious if you’d purchased from Phoenix welding supply, there prices seem high, but when your the only gas and true welding supply you can charge whatever you want I suppose.

[KensAuto]

Praxair is the same way, a large company.
There's also one of those down there.

Consolidated Welding Supply looks like a mom and pop place, on the south side.
Been there?

[JR]

We have a praxiar local but I drive to a welder supply in Napa. Cheaper and better.

[wyorunner]

I’m not sure if was consolidated welding or not, it is on the south side though, the store I’m thinking of in Tucson. Only been there a couple times.