As expected, it wasn't difficult to apply B2 sealant to the access plates on the top of the right tank. Overall, it took about an hour and about 3/4's of the jar of sealant.
As expected, it was much more difficult than it should have been to install the fuel drains. The instructions on page 13 are deceptively simple -- Install (1) into (2), where (1) and (2) refer to the fuel drain and fuel tank, respectively. It doesn't mention using anything to create a seal, but I know that those types of threads (NPT) aren't actually fluid tight and must have a sealant of some sort. Basically, it boiled down to using B2, as is used everywhere else, or Loctite 565 which is called out in a different chapter but never mentioned in the actual instructions. I posted a query on VAF and was told RTFM (section 5) where it generically calls out Loctite 565, so that's what I went with.
As mentioned a few posts ago, I had tried a simple trial fit by installing (finger tight only) those components, and somehow managed to strip threads. I wasn't really sure if they were stripped inside the tank (horrible) or just on the $30 part (not too bad).
I researched the drain and found that it was a 1/8" NPT. I couldn't find any technical description of the threads for the part from Van's. It appears that all 1/8" NPTs are 27 pitch but that was only because that was the only pitch number I ever encountered and it was rare to find it at all. I bought a set of cheap taps & dies at Harbor Freight that included the desired NPT. I've tapped internal threads before, but never cut or chased external threads.
Some scrap Al from the RV12 was used to make a test hole with the tap and I was able to thread the fuel drains into that. This confirmed that they were indeed 1/8 NPT 27. I debated chasing the external threads on the drains, but wasn't sure which side of the die was the starting side. Since NPTs are tapered, doing it backwards would probably destroy the part, so I deferred. In retrospect, I think running the drains through the test hole actually chased them a little anyway.
The tap was used to very gently chase the tank. I only used finger pressure and no tools. The drains got gooped up with 565 and I tried to install them. Nope, the threads wouldn't engage. I finally got them to engage and tighten by pushing up on the drain with my thumb to and apply a fair amount of axial load while gingerly rotating them with a closed 1/2" wrench. Finally, success. It only took an hour to install two bolts.
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