greets all. started today on a 20' stainless steel indoor railing (stairs) -- and have finished the first 6' with ugly results.. and after all that notching/fitting.
don't know where to post pictures -- but a quick description: the rail is composed of
3 horizontal 3/4" thinwalled stainless steel tubes, spaced about 6" apart, with short (6" long) 3/8" thinwalled SS tube vertical pieces to tie the horizontal ones together.. spaced about 3' apart, and offset between each horizontal tube.. think "brick wall" pattern: 3/4" horizontals and 3/8" verticals.to keep the SS looking nice i'd laid the first section on a sheet of plywood and used blocks/woodscrews to hold the pieces in place. cut, fish-mouthed, and fitted all the pieces.. it was looking great.. tackwelded everything in place (small tacks on each tube end 180deg apart to try to keep them from moving)..
flipped the 6' section over (remarkably light), and started in with the tig. 1/16" tungsten to get as small and inconspicuous a bead i could. tig @ about 50 Amps. welded one side (halfway around each tube, connecting the tacks from before), flipped it, closed the welds on the other side.
i stood back.. and i saw it. the whole thing bent up like a noodle. it stayed flat (in the plane of the railing), but my 3/4" horizontal tubes now look like waves.
tried to do my best to keep the heat down.. but what did i do wrong? and how can i keep this from happening on the rest of the railing? (heavier walled tubing would've probably helped, but i've already got it all here in the shop)
any thoughts/suggestions greatly appreciated
-tony