During the past week, we successfully pressure tested and attached both fuel tanks. Pressure testing involves filling the tank up with pressure, via a hand pump, and then using soapy water to try and find bubbles that show up when there's a small hole in the tank sealant. It's kind of like trying to find that hidden leak in your car tire. Too much pressure in the tank can cause the integrity of the sealant to be compromised. In order to prevent this, you put a balloon on the end of the fuel vent line instead of closing it off completely. Theoretically, the balloon will bust before the pressure in the tank gets high enough to damage the seals. The left tank test went fine and didn't present any leaks. The right tank had a small leak around one of the pop rivets used to attach the tank baffle. We were able to apply more sealant around this rivet and close up the leak.
Initially, Brian struggled to get the tanks on the wing spars. There was one zee bracket that would just not line up on either tank. He called Van's support and they told him to drill out the bad zee and re-seat it in the baffle so that it would line up with the spar. I chuckled a little and thought - No Way! After messing around with it for a while, he discovered that the edges of the zee's were very tight up against the spar and thought maybe that was the cause for our issue. After sanding down some of the zee edges, both tanks bolted on perfectly. =D