I just finished welding together the stainles racking cane for the beer fermenter project.
Even though this may not look like much, I am quite proud. It is a 5/8" dia stainless tube, but the wall thickness is only .020". I sliced it on my new metal band saw, reoriented the pieces to make an elbow, then tacked it in two places, and welded all the way around. It's air-tight. The trick is to get the tacks done really quickly. I only used filler (.035") to make the tacks, then just fusion welded it in very short sections (a few seconds at a time). I blew through it once, and had to repair it with filler.
Here's the tube welded to a tri-clamp plate, which is welded to one side of a three-piece ball valve.
Here's the other side of the ball valve welded to a hose barb.
The complete assembly is attached to the tri-clamp port on the side of the tank. The purpose of all this hardware is to be able to rotate the racking cane while draining beer from the tank. Thus, the height at which the beer is drawn can be adjusted. This allows the maximum amount of clear beer to be drawn from the tank without getting any cloudy beer that has settled to the bottom.
Inside the tank.