So, after several attempts to properly install the fittings, I was able to finalize everything with the right components and sealants to test for leaks. I originally made the mistake of using standing pipe tape on the fittings based on several comments read from other builders – or at least that was my interpretation. Finally, after a discussion with Mark Pringle at Rocky Mountain Kitplanes, I ordered a very small tube of Loctite 567.
The test began on Saturday (3/23/19) at 9am. I started with 4 gallons of water in each tank checking for leaks. I figured that it would be easier to dump out 4 gallons of water if I experienced major issues instead of trying to pick up a gas tank with 11-12 gallons of water. I had a few minor leaks on the 45-degree coupler, but they were easily resolved by tightening the nut. After 2 hours, I added another 4 gallons to each tank – no leaks. After 2 hours, I added another 4 gallons. I checked throughout the day and before I went to bed at 10:30pm – no leaks. Again, this morning, at 6:30am no leaks.
My next step is to test the upper (fuel sight gauge) fittings today by plugging the ends of each and leaning the tanks on their sides to put pressure on those fittings. The left wing (as is shown standing on its side) tested successfully. The right wing fuel sight gauge did not. I had to remove the fitting, clean out the loctite Blue with Acetone (after removing the rubber washers, and get ready to re-install.