Building turbo manifold, all pipes are 304 stainless sch 10 (same as 12 gauge). The guy that is helping me build it said that he built stainless headers for a drag car (small block v-8 runs high 7's) and this is how he did it....
Used a MIG welder to connect the pipes, stainless wire and some kind of different gas, Helium? or something. Anyway, he said after he mig'ed the pieces together, he went back over the welds with his tig. He said basicly used the mig to apply the filler material and then finished it off with the tig. They turned out really nice, maybe not nice for some people on here but it looked really good to me.
He has made many other headers before and has been racing for a long time. Last set he made was aimed to look good also. They were made from 2 1/4" mild steel (yes each cylinder had a 2 1/4" runner ), miged together, weld smoothed up with grinder, sent off to have chromed. Car ran best of 8.12 with the smaller engine (565 BBC NA). But anyway, enough story time....how well would this idea work on a turbo manifold? and what gas should be used to mig stainless?

 

You can do that, yes; most people will just opt to tig the whole thing in the first place though.

One advantage of mig'ing the pipes together then laying down a final bead with a tig is no need to backpurge the pipes; however you want to be sure that there are no welding dages inside the pipes after mig'ing.

 

yea that is my next thing to worry about. I'm sure i will check after each weld. He migs 95% of his stuff and is getting more and more into tig. He has built rail cars and full tube chassis cars. I was just not sure if this was ok to do. his mig welds are amazing but still not like tig.

 

mig is gonna be just as good. its just doesnt offer as much control thats all. For some people, if it makes power and doesnt break its good enough.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bailhatch &raquo;</TD></TR><TR><TD CLASS="quote">For some people, if it makes power and doesnt break its good enough.</TD></TR></TABLE>


amen.

 

That'd work. Mig is a lot easier when mocking stuff up because you can just hold the pipe with one hand and tack it with the other. If you mig it up right there really is no reason to go over it with tig. Mig produces a wider bead so anyone that knows what they're looking at would be able to tell the difference.

 

I tried to tig over a SS down pipe that was partialy fluxcore welded together by someone and he wanted me to tig finish it and all I got was contamination. I cleaned everything as best as possible but soon as I hit those welds everything went to ****. I hate to say it but I fucked up that one