Was a nice day outside, so I decided to do the left tank test. I used some electrical tape on the vent line fitting and two pieces of safety wire to try and get a good seal on the balloon. This worked well. I pumped up the balloon with a bike pump and took the tank out out on the porch. Jason and I were able to do a very close look at all the rivets to see if any were making bubbles. There were no leaking rivets at all! Both tanks done with no leaks. Hurray!