[rv9aviator]

I had a small drip coming from the inboard rib right at the top back corner of the tank. It only leaked when full but I pulled the tank yesterday and removed the large round cover plate to get access to the leaking corner. Upon inspection I couldn't see any reason why it was leaking. There was a nice bead of ProSeal covering all the corner joints and looked like I did a good job. I decided to remove all of the ProSeal in the corner and reseal. In the process I noticed I could get a fingernail under the proseal and it would lift up. The problem was I failed to scotchbrite a small area on the end rib and the ProSeal couldn't get a grip on the aluminum. Moral of the story is, Make sure everything is scuffed up anywhere you want the sealant to stick and make sure the area is absolutely clean and dry. This could have been caused by oil from my hands and not being scuffed enough. On the good side, I built the tanks and the plane so it took only about an hour to remove the tank and another hour to fix the problem with a total cost of ZERO! Don't you just love experimental aircraft.