LOTS of priming for the ailerons and flaps

The remaining aileron parts were long overdue for getting primed, so I planned to at least get them done while I had a good day to do so. I put the leading edge skins, counterbalance pipes, doublers, spars, and ribs on the priming racks, and I realized I had plenty of room to fit most of the remaining flap parts too (which were also ready to be primed at this point, so why not?).

Turns out I could fit every remaining flap and aileron part onto the racks except for the flap spars and skins.

The only metal work left on the flaps was to machine countersink the holes in the bottom of the spars to allow the hinges to sit flush. I briefly considered trying to finish all of the countersinking before prepping the parts for priming, but I was concerned that I'd run out of time if I did that. Instead, I decided to go ahead and prime the spars and countersink them later. I can always spot prime the countersunk holes if I really need to.

With an abundance of parts to prep, I prepared myself for a LONG day in the shop. Scuffing and cleaning everything took around three hours, with an extra hour dedicated to wiping each part with acetone. Planning ahead, I mixed up a bit more primer than I thought I would need in preparation for priming the insides of the counterbalance pipes.

I mixed up around sixteen ounces of primer, which turned out to be more than enough to cover everything.

Priming the initial group of parts only took around twenty minutes. Once the aileron skins and spars were dry to the touch I moved them onto some cardboard-covered sawhorses to get them out of the way, then replaced them with the small lower flap skins now that there was room on the rack. I did the same thing for the rest of the smaller parts on the other rack, replacing them with one large upper flap skin at a time.

Once the rest of the parts were done, I turned my attention to the counterbalance pipes. Priming the outsides was as straightforward as the rest of the parts, but I needed to protect the interior surface of the pipe as well. While scuffing the rest of the parts earlier, I made an improvised tool for scuffing the inside of the pipe by sticking a trimmed-down Scotchbrite pad onto an unbent coat hangar. It works better than it looks.

I taped up all of the holes in the pipe except for one end, then poured in the primer making sure to hold each end tightly to keep any primer from leaking past the tape. At that point I rocked the pipe back and forth while slowly rotating it, making sure that the primer would coat every square inch of the inside surface. This is the same method I'll need to use later on for priming the insides of the elevator and aileron pushrods, so it was good to get some practice now.

The frog tape on the very end didn't work well at all and let a bunch of primer leak out as soon as I poured it in. I actually managed to find a small rubber plug to stop one end and I held the other end closed with the palm of my hand.

At the end of the day I glanced at the clock and realized I had just spent about eleven hours in the shop. It was well worth it though - literally every part that I needed to prime got primed.

Such a satisfying feeling. That's a lot of parts!

Learning from last time, I'll wait 48 hours for the primer to fully cure before I start dimpling anything. Soon enough I'll have both the ailerons and flaps done, then I can move on to the main spars and get the wings started proper.