316 SS Tig welding with 308L mig wire

[Robert1998]

Hi everyone

Yessssss I´m crazy haha. No really, I need to weld with TIG thin 316 SS sheet. I only have a tig welder and instead using 1,6mm welding rod I want to use 0,8mm 308L mig wire. So 2 questions

I know you need a higher or equal grade welding rod/wire to weld SS. For example with 308 you can weld 308 and 304 but no 316. But this welds are NOT structural. Is only sealing a pipe to make it airtight. No forces no stress, just sealing so no cracks allowed. Can I use 308 wire on 316 sheet for that purpose?

And, I think there is no problem, but I can use this MIG wire as a welding rod for tig right? Is regular wire to use with gas, no flux.

Thank you

Best regards

 

[chrismac]

Hi, yes no issues using your 308 mig wire to weld your 316 pipe, you wont notice a difference.

Chris

 

[hotponyshoes]

For that application 308 will stick it together.

But you'll have to feed 0.8 about 4 times faster than 1.6 so will be harder to get the filler in. Plus it's hard work to straighten it out.
Maybe take 3 lengths of mig wire and twist them together with a drill to increase the volume and make it stiffer?

 

[Robert1998]

Thank for your answers

No no, I have 1,6mm 316 welding rod. The problem is the sheet is thin, and I am not very skilled in TIG welding, so I preffer a thin wire

 

[chrismac]

If the sheet is thin you can use a backing strip, some flat bar, angle iron which will serve 2 purposes, it will aid keeping the 2 piece aligned and act like a back purge meaning it wont oxidize, if its possible to do in your set up,

 

[hotponyshoes]

Thank for your answers

No no, I have 1,6mm 316 welding rod. The problem is the sheet is thin, and I am not very skilled in TIG welding, so I preffer a thin wire

I'm not very skilled either.
But I sometimes (mostly) find a thicker wire easier to use.
You have to feed a thin wire in quickly.
A thicker wire also cools down the weld puddle which is handy on thin sheet.

If you get on better with a thinner wire then use that. 0.6 is readily available as well.

Although tig filler is pretty cheap so I think I'd just be buying some 316 in whatever size I wanted.
I've tried uncoiling mig wire before and it's got the potential to get messy quickly!

 

[Robert1998]

Thank you. Ok I'll try that

 

[RichardM]

I used flattened copper water pipe on the back to act as a heat sink when welding thin stainless. Also helps with sugaring, but would be best with a purge system.