which is better

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which is better to butt weld 14 gauge stainless without warping ... tig or mig? I am trying to use a miller dynasty 200 dx with a 1/16 tungston and 1/16 filler rod and am getting some warping. I am cooling with wet rag and staggering. there is a3/16 backing strip on the one piece. I think it is better fitting up the joint and not tacking the other side of the backer strip? I dont have any experience with stainless mig welding so any detailed  help would be appreciated.
Reply:What is the joint configuration?
Reply:A butt joint with a backing strip.I have not done long butt welds on thin ss, but on small thin cylindrical butt welds that I've done, I like a fairly radical pulse with a short time, high current peak pulse of maybe 20 - 30% on-time to melt a spot, with a super low background current like 5 amps just to keep the arc going and allow the puddle to chill, and low pulse frequency, so that you are producing overlapping spot welds.
Reply:pulser. write a book. i'd buy it.http://kawispeed.com/ -moderator and tech deluxewww.myspace.com/trickortrack -cuz i have no life
Reply:tjfxg,In your other post on this subject under the General heading, you mentioned concavity.  In a perfect world, the joint edges would be square and there would be no gap in the joint, so an a small full penetration weld could be made without adding filler and without concavity.  But since the joint edges have been deburred or chamfered, and the joint has some gaps, filler is needed to prevent concavity.  Also, excessive weld size/penetration leads to concavity.Pulsed parameters can produce an equivalent weld to a constant current weld, but at a lower average current/heat input, and hence less distortion and concavity.Seam welding machines use precison joint preparation and fitup, along with tight clamping copper chill bars/backup along the top and bottom surfaces, and low heat input parameters.  These systems may use high speed to achieve low heat input versus the pulse approach.Just throwing out some stuff to think about.