Once right wing tank was completed and all sealant cured. I attached a small balloon to a piece of tubing and attached inflated to the vent fitting. Covered the tank is soapy water. Discovered a small leak in the shaft of the fuel cap. Removed the fule cap and applied pro-seal to the shaft threads and underside of the lock-nut and reseated the internal O-ring. Re-installed and refilled the balloon. The tank has been holding constant pressure for 4 days now and in fact expands and contracts when the tank heats during the day and cools at night. NO LEAKS!!!!
I really spent a great deal of time ensuring every possible leak area was prepareed and properly sealed. Every joint was neatly fillet'd with pro-seal, every rivent head was covered. Every joint completely covered in proseal prior to riveting.
If I a leak occurs the best course of action would be to cut small access panels in the offending bay at the baffle and seal from the inside. Then rivet or nut plate the panel in place with plenty of sealant.
