Finally finished the fuel tank, and set about to test it. I have been so careful to seal every crack and seam, I KNEW there would be no leaks. Hooked up a hose and food coloring water in it, pressurized the tank - and it has a large leak someplace, the water comes back down in a big hurry. Don't take much pressure either, what appears to be the very slightest pressure changes the tank from square to round. Too tired to find the leak tonight, got to have a project for tomorrow. The second photo shows if you look closely, that the levels of the colored water are quite even, indicating no pressure in the tank.