Originally Posted by
trackmaster
Hello Woodchuck, if i may add my 2 cents worth - Firstly and you may already have done so, but practice on some mild steel for a bit, (or stainless if practical), they both weld so similarly that once you gain experience you will not even really think about any difference in technique, other than it being more heat sensitive (retaining). Practicing on aluminum if you are new to tig is great for gaining confidence on aluminum, but ferrous metal as ya know welds way different.
Second it sounds like basically a circular if you will, fillet weld around the coupling where it mates to the tank? Tank being .050, what is the thicness of the coupling? Also 1/8 stick out may be a bit tough for a newer tig welder on "that" specific joint, try more stickout so you can better control torch stand off etc. Yes you would always like to have as much of the tungsten shielded, and the cup close to the weld zone, but it sounds like you could be having some trouble seeing what your doing, even with a number 5 cup. When ever possible try to use a gas lens. With the supplied torch i think an 18 series lens and collet, cup assembly. Yes the cup is fatter on a big 18 series but you can get away with a pretty big tungsten stick out with a lens, as the shielding gas is directed in a much better coverage area.
Are you purging the entire tank? Over purging causing turbulence at the joint? maybe try a makeshift purge box to just shield the back side of the immediate weld zone (save a lot of argon too). Lastly what color is the weld coming out to be? Looks to cold? too hot? burning holes or notches?
love to help anyway possible, - Lou