Yeah 304L thanks for input got plenty to mull over now will let you know how i get on with it being able to quench is good as there could be a number of them. if you was doing a long run on stainless say 300mm long Butt weld 2mm sheet would you weld a bit quench weld a bit quench to stop to much heat getting into the job obviously staging the welds?
Step back technique will help with this. Start an inch or so from the left, weld left till you get to the end,?do the same halfway along the butt, then the last inch on the right. Dab with a damp towel or a spray bottle (don't submerge or you'll end up with moisture in the seam)
Then repeat the welding process from left to right (reverse if you are a lefty) and this will help to keep heat input down and reduce distortion. You may still need a preset bend in the sheet to avoid a curve in the finished article.
Yeah I do use skip/back stepping method but I was wondering when you quench do you do it per run or say do left middle right? I say quench but I'd use squirty bottle an blow dry with compressed air. And do you take your time when welding stainless? I.e let the weld cool then weld a bit let it cool weld a bit. When I'm laying a bead on stainless my best results are when I move fast and keep my amps low.
Like you say higher travel speeds work better/typically result in lower heat input than moving slower. I don't really take my time unless i get talked into doing something i think is a bad idea... usually i'm designing it or at least have some input so generally get to avoid stuff like having to butt weld completely featureless flat sheet and trying to keep the thing flat. Beyond that it all depends, sometimes might be able to use pulse and weld autogenously in which case i might zip the joint up in one go without stopping travelling at 2 - 3 X the speed i can manage with filler. Other times i might backstep it. The only constant with thin sheet would be lots of small tacks