Initial Prep (Debur, Trim, Drill, and Cut) 12/6/22 – 1.9h The vent lines are made from a coil of AT0-032 x 1/4 soft aluminum tubing. The tubing is coiled for shipping, so it took a little time to hand-straighten it. When the tubing was roughly straight, I measured two lengths of 54 1/16” tubing. I used a tube cutter to cut the pieces to length and deburred both ends before flaring the inboard end. I used a tube flaring tool to flare and burnish the inboard end, which I then fitted with a nut and sleeve to attach to the fitting in the aft inboard rib. I noticed a problem at this point when I tried to dry-fit the aft inboard rib. The last rivet on the top and bottom of the tank attach bracket is also used in the aft rib. I remember thinking it was odd that the rivet schedule used a slightly longer rivet in these two 9(top and bottom) holes, but I missed the note that says not to rivet those holes in the previous step. The result was I had to drill out four rivets (two in each tank) before I could try to dry fit the aft inboard ribs again in order to align the vent lines properly. Lesson learned… if something looks strange in the plans, look at all the notes on the page before proceeding! [Hole Edge Deburring Tools, Scotch-Brite Pad, Tubing Cutter, Tube Flaring Tool] Final Prep (Dimple, Countersink, and Shape) 12/7/22 – 0.5h The vent line needs some slight bends in the inboard and outboard tank bays to align the ends with the vent clip on the fuel filler flange and the vent fluid fitting on the aft inboard rib. The vent tubing is soft and easily bent by hand. I tried to maximize the bend radii to avoid creating kinks in the line. The bends also help set the gap between the end of the vent line and the outboard rib by the fuel filler. Assemble 12/5/22 – 0.7h 12/11/22 – 2.0h 12/12/22 – 2.5h 12/13/22 – 1.0h 12/14/22 – 2.0h 12/17/22 – 1.2h It was a nice break to get an easy step after 2+ months of riveting and sealant in the previous section. The bulk of the riveting and sealing is complete, so this was a good opportunity to inspect the sealant job and add sealant as needed to problem areas. I asked a fellow RV-14 builder to look at my tanks. In addition to pointing out a few areas for additional sealant, he noted that one of the problem areas on the tank is the fillet on the forward side of the tank attach bracket. That fillet is formed blind since you can't see that joint after the bracket is riveted in place. The fillet was mostly in good shape, but I put additional sealant in the corners to make sure that area was as good as I could make it. We also talked about leak testing the fuel tanks. The final leak test doesn't happen until the tank is complete, which means there's no way to make repairs (if needed) without cutting the tank open. I'd really like to find leaks prior to that point, so I'm brainstorming some ideas to do some limited leak testing before installing the rear baffle. The first step in this section is to install the fuel vent lines. The vent line snap bushings, tubing, and fitting hardware goes in quickly, and then the tubing is shaped by hand to align with the vent line clip on the fuel filler flange and the vent line fitting in the aft inboard rib. I cleco'd the aft inboard rib in place, and dry fit the fluid fittings to help align the tubing and ensure the tubing had the appropriate gap by the vent line clip. A quick return to riveting and sealing is required to install the aft inboard ribs. I biased the sealant toward the inside half of the rib flanges, and then riveted the ribs in place with a hand-squeezer. There are also 6 AN470 rivets that connect the aft rib, forward rib, and tank attach bracket. I managed to set the 4 center AN 470 rivets with the hand squeezer, but the access to the two end rivets required me to go to a double-offset cupped set in the rivet gun with an angled bucking bar to get into the tight corner. The rivet gun made quick work of the final 2 rivets on each aft inboard rib, which completed the riveting for now. I like the way Van's gradually introduces new skills as the build progresses. The new skill in this case is working with fluid fittings. The plans have a cryptic instruction to, “Thread the nut onto the bulkhead union and torque the nut.” That brief instruction was the clue to review Section 5 of the plans for additional detail, which in this case is Section 5.27 – Fluid Fittings. There are 3 notes in section 5.27 that are particularly relevant to the installation of the vent line fittings: 1) Torquing the nut on the fluid fitting is different than the torque specs for AN hardware. The procedure is to, “Thread the fitting in with your fingers until you just begin to feel resistance and then an additional 1.5 - 2 turns.” 2) Special sealant is required on the fluid fittings. “Because we cannot always fully tighten tapered thread fittings, and because even after fully tightening the fitting a small spiral leak path remains along the full length of threads, a thread sealant must be used during assembly. Sealants appropriate for use on aircraft NPT fittings are Tite-seal, Permatex #2 and Locktite 565. Do not use RTV, Teflon tape or Fuel Lube on NPT fittings.” I ordered a small tube of Locktite 565 for my vent line fittings. I also plan to use a small amount of tank sealant between the web of the inboard rib and the flange on the fluid fitting. Locktite on the threads, and sealant on the flange. 3) The plans direct the builder to, “apply a small amount of sealant [Locktite] to 2 - 3 threads of the male fitting. Leave the first 2 bare to prevent contamination inside the fluid path.” I put a little sealant on the flange of the fitting where it contacts the interior side of the rib, and used Locktite 565 on the threads on the exterior side of the fitting to minimize the likelihood of fuel working its way through the threaded portion of the fitting. Torquing the fitting felt a little strange. I threaded the nut on the fitting finger tight, and then marked the nut to keep track of how many rotations I made to tighten the nut. The first quarter turn provided firm resistance, but then the nut became very easy to turn for the next 2 quarters of rotation. It then firmed up again, and became very firm when I had completed about one and half rotations. I decided to stop at that point to not risk damaging the fitting. The same was true of the fitting inside the tank to connect the vent line, and it also took about a turn and a half before the resistance started to dramatically increase. I finished the step by encapsulating the interior fitting with sealant. [Rivet Squeezer, Flat Squeezer Set, 1/8” Cupped Squeezer Set, 3X Rivet Gun, Double-Offset Rivet Set, Tungsten Bucking Bar, 11/32 Socket and Ratchet, Crecent Wrench, Locktite 565]