Wire for Stainless

[Punx0r]

Hi guys.

I'm doing a stainless downpipe for my car, doesn't need to be pretty and the cheaper the better really.

I have the 304 pipe and a search on here suggests 308 would be the correct stuff to use.

However, I was planning on winging it with the gas and using pure CO2.

So my question is, will this compromise the welds to the point I might as well just use mild steel wire (which I've done before) and save myself the £20 of the stainless wire?

Yeah, I know it's a bit pikey...

Thanks,
Anthony

 

[shenion]

Stainless needs a low CO2 gas or it will pick up carbon and likely become brittle. Usually less than 5% CO2 is used.

You can use pure argon if you are on disposables but the welds will be tall.

Argoshield light will work. Maybe you can borrow some or tack it together and have someone else finish it.

 

[langy]

Can't you tack it with the mig and then get it tigged properley ???

 

[Punx0r]

Hi guys, thank for the replies.

I'm on a rent-free refillable CO2 bottle, but the supplier doesn't do argon (or mixes) and doesn't know anyone who does locally. So I'd have to buy a pure argon disposable and regulator.

I've read that welding stainless with CO2 will make the welds brittle to some extent (not sure how much) and reduce their corrosion resistance. If there's a risk of breakage or they'll rust like mild then I might as well just weld it up with mild wire, which I know from experience works fine (apart from the rusting).

This is a bit of an experiment and I'm doing it on a tight budget. As long as it's gas-tight and doesn't fall apart then it'll do everything I need it to!