Stainless process pipe

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I am a maintenance man in a paper mill.  We occasionally have a stainless pipe crack or need to be repaired.  It is usually just something that needs to be patched.  The lines are mainly contain water and or paper pulp.  Would a small lincoln weldpak be a good choice for this?  I have a weldpak 100 at home and would like an excuse to upgrade mine at home and take the weldpak 100 to my toolbox at work.  Usually the pipes crack in an area that is difficult to get a stick into, but I cant think of an area that I wouldnt be able to reach with the mig gun and small welder.  Our pipes are mainly 3/16" thick and 316 stainless.  Like I said it would just be patch work, as long as it doesnt leak bad the paper fibers plug the hole.  I just think the mig would be a bit safer and more convienent than the stick.  Any thoughts?Thanks, Rob....
Reply:to just tack patches on, MIG would do i suppose but TIG would look better and cleaner. depends what is required.  metal sticky tape could possibly work too.some might say its imposible
Reply:A repair made with that little MIG may not last long.  Are you patching these with the pipe in service, or depressurized and empty?Difference being that if you can get the pipe empty, you can grind out the crack completely and fill with multiple passes, needing to run that machine wide open with expensive proper shielding gas.If the pipe is staying in service during the repair, all you can due is essentially "hot glue" a piece over the top, but the crack underneath will propogate and tear the patch.Sorry, but there is no excuse for a paper mill with stainless piping doing their own repairs without the appropriate equipment, and an employee bringing in their 120V MIG isn't it.If Stick is available, it's a much better choice.  Curious, why would you think MIG might be safer?Last edited by MAC702; 05-29-2006 at 07:51 PM.
Reply:The  process would be shutdown to patch the pipe, but it is not always possible to completely drain all pipes of its contents.  Metal sticky tape wouldnt do, up to 100 psi on some pipes.  Just in a tight spot, on your back, underneath other equipment, I figured it would be a bit easier  and I wouldnt have to worry about touching the rod with wet gloves and knocking my backside off.  Appearance isnt an issue as long as it gets up and running is the issue.  I just wondered if it would make it easier for me...  Thanks for the suggestions.
Reply:If you weld patches on, you'll have overlapping layers of stainless steel which is a breeding ground for crevice corrosion.  I suggest you just stop drill and weld in the crack and not use patches.  Brazing with 50N silver brazing alloy may be a practical solution because it is unecessary to purge the pipe.  That section of pipe will never be able to be welded again, only brazed.  The practicality depends on the size of the crack, the high silver brazing alloys cost nearly $20 per troy ounce.  I've never tried brazing anything overhead, how well does that work?For welding, stick is certainly the most practical method for this kind of repair.  MIG is just too finicky.Last edited by 76GMC1500; 05-30-2006 at 01:27 AM.