So how close does the tungsten need to be to the surface? Tight. Ideally, the arc length should be roughly equivalent to the diameter of your tungsten and should stay fairly consistent without touching the tungsten to the molten metal. Definitely no more than 1⁄8 to 1⁄4 inch away from the weld puddle. Also, use the push technique since that ensures good shielding gas coverage and better visibility of the weld puddle.