Mig welding SS 304 Pipe?

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I know i have to use the solid type wire with gas, argon/oxy i think, is there any special method to do this to minimize leaks for 3" stainless steel exhuast pipe?  Ive welded a few times already, no pipes though, im assuming i can butt them together end to end and weld around the area where the two pipes meet?  I have a lincoln Pro Mig 175 i think, its brand new, it has settings i think for heat like A/B/C/D/E .. C seems to do well on heavy metal i was working with. Should i use another for thinner stainless pipe or hotter?  Thanks!
Reply:dont weld stainless steel with agr/ox use arg/co2
Reply:Definitely no oxy in the mix.  Whole point of the shielding gas is to shield the weld from possible oxidation.  You should have a chart either on the machine or in the owner's manual with some recommendations on heat settings and wire speed for different thicknesses and materials.  For welding pipes, it may help to buy or fabricate a jig of some sort that will hold the pipe and allow you to roll it as you work around it.  The hardest part will be getting to the point where you can maintain a steady speed around the whole pipe.
Reply:98/2 with oxygen will work just fine if you're doing spray transfer.  C25 will work if you're doing short circuit, but trimix is preferred, which is 90/7.5/2.5 Helium, Argon, and CO2, respectively.  You should back purge the pipe to prevent carbide precipitation on the inside.-Heath
Reply:I agree...  98/2 will work fine.  Tri-mix is a bit cleaner though.
Reply:If I were you I'd start by doing one of two things, Go to your local gas and welding distributer and ask(Prax-air is mine) there staff "SHOULD"  be able to help with any questions.Also I'd go to Lincoln's website. I haven't been to Lincolns but I,ve been to Miller's and they have Machien setting charts and Q&A forums. Bapnbird
Reply:have you guy tryed useing 98/2 ar/c02 for stainless steel spray?ChuckASME Pressure Vessel welder