I just made one tonight (soldered) and it doesnt work. I have a female 1/2" coupler on the inside of the keg connected to the spigot. From there, I made the dip tube. The dip tube is all copper, consisting of a male threaded piece about 6 inches of 1/2" pipe, a 90 degree elbow and another couple inches down to the bottom of the keg with a little bit of room to spare between the bottom of the dip tube and the keg. I tested with water filling it just above the spigot on the inside of the keg and opened the drain. The water drained out until it reached the bottom of the spigot but still left the remaining 2 gallons or so in the bottom. I also tried connecting a piece of nylon tubing to the spigot on the outside of the keg and let that hang down below the bottom of the keg and the water still stopped at the same spot leaving those 2 gallons inside. What could be going wrong?