We were expected to TIG-fuse those 16 gauge stainless steel pipes without using fill rod if at all possible. When the heat was adjusted properly and the wind didn't blow the argon shield gas away, the weld bead was less than 1/8" wide and did not build up above the surface of the outside of the pipe. We used a needle-sharp 1/16" tungsten electrode and about 40 amps or so of current, and the pipes were machined to a perfectly square fit with a special cutting tool prior to clamping the pieces together. Two 20-foot sections of pipe would be welded together on the ground, then hoisted into place by a crane or a manlift and welded into place in the overhead racks. We ran over 40,000 feet of 4" stainless pipe between February and May one year in a small modification of the piping system of the winery.
Jerry
