This morning I ran one more pressure test on the fuel tank. I pressurized the tank and then mixed up a soap solution and began testing all of the seams, joints connections and fasteners. I worked in the shop and rolled the tank from side to side and top and bottom applying the solution to all of the edges and rivets. I tested the sight window with all of the fasteners holding it in place. I continued to test all of the surfaces and found no leaks. I then tested the balloon attachment to the fuel strainer fitting. No leak. I tested the air hose connection to the fuel return line fitting. No leak. I then tested the air valve connection to the air hose. Voila! As I put the soap solution on the end of the hose it began to blow a bubble. I wiped it off and applied new soap. A bubble immediately began to form. I used a nut driver to tighten the fitting and the leak stopped. The balloon has been inflated for several hours now and there is no sign of it going down. HURRAY! I will leave the balloon on for several more hours and we will see what happens. I am sure it will remain inflated for several days now. That was the only leak I found and it was slow enough to allow the balloon to remain inflated for long periods of time, but eventually the pressure decreased to the point that the balloon deflated. I am glad to have that problem behind me. I am glad that it was not the actual tank that leaked.
This evening after the balloon remained unchanged for several hours I decided to mask the fuel tank and filler tube so I can apply the primer and finish. I masked both ends of the filler tube. I then masked the tank.
The only portions of the tank that will be seen include the forward end, the fuel level sight window area and the area around the top flange and the rear attachment point. I masked all but these areas so the tank is now ready to be wiped down with MEK and then primed and painted.
