Plans have you at this point back rivet the stiffeners to the elevator skins. In order to do that you need to prime the inside of the skins and prime the stiffeners. Also for the left elevator you need to rivet the trim tab cutout doubler plate to the inside of the skin as well. So nothing too exciting here, just work. Priming the parts was easy enough.

So as not to confuse left and right stiffeners, I decided to just do the left elevator first, starting with one side of the interior skin and then priming and riveting the opposing side. With the first batch of stiffeners painted and the skin painted, time to bust out the back riveting set and plate. Plans have you rivet the trim cutout doubler plate on first. I couldn't really see a good reason to use the back rivet set for these so I just bucked them with a bar. I've gotten comfortable enough to prefer that method over all the others, funny how your opinion changes over time and you get better and better with riveting. Unfortunately to make a long story a bit shorter, I failed to identify all of the holes that needed to be drilled and dimpled to attach the backing plate and started to rivet it together before I realized what I had done. Dumb, dumb, dumb..... Easily avoidable if I would have been a bit more careful! To make matters worse, after I corrected my initial mistake, I STILL didn't get all of the holes dimpled that I needed to attach the doubler plate AAAAAAAAAAAAARRRRRRRRRRGGGGGGGGGGGGHHHHHHHHH! Literally spent 45 minutes drilling out rivets after previously spending about 20 minutes drilling out the first set that I placed prematurely. Trying to dimple a hole that you basically have no access to is a challenge to say the least especially when it's two pieces of AL stacked together. So this whole ordeal took the better part of my free time that day.

A word on back riveting. It is used to make sure the skin stays as flat as possible to the piece/s being riveted to it. So the doubler plate was supposed to be back riveted as well but it was easy enough to just buck with a bucking bar. Should I have back riveted it instead?? Good question, I see no difference in the final result in what I did versus using a back riveting technique.

Moving on to the stiffeners..... Next day was spent trying to back rivet the stiffeners to the one side of the interior skin. After researching my back riveting technique and getting some info off of VAF, I started with a very low air pressure setting on the gun. This initially worked well for the four or five half-sized stiffeners near the trim cutout. I did tip a couple over and yet again spent time drilling them out. After a couple days of screwups I got really good at removing 426 type rivets! Then it was onto the larger stiffeners and that's when the problems started. Seems like out of each row of back rivets 2 or 3 were either smeared or tipped over. Very frustrating as the time that it took to correct them is not insignificant. At one point I said screw it and used the bucking bar to set almost an entire row with acceptable results. That's when the doubt started to creep into my mind about what was really the best way to attach these stiffeners. Vans is obviously calling for them to be back riveted for a reason. I just hadn't figured out that reason quite yet. So this mental struggle continued the rest of that day, setting with the bucking bar until I realized that doing it this way truly was not the best way to ensure the stiffeners lay perfectly flat against the inside of the skin. So realizing that, once again I found a few perfectly set rivets that I needed to drill out and use the back riveting set for to get them in contact with the skin beneath. That was a very frustrating day. There will be more I'm sure.

Next day I began anew and decided to make this back riveting work come hell or high water. Frustrated with the results of the back riveting, I switched the set out to an offset back riveting set but the results were even worse. Then it dawned on me that maybe increasing the air pressure would help. All week I had read on VAF about how other builders were using very low air pressure on their back riveting. Well for whatever reason, the low pressure wasn't doing the trick for me. So lightbulb moment, up the air pressure you dummy! I was using about 25 psi to start. I bumped that up to 40 psi and the results still were not acceptable, a couple more tries and I finally settled on about 60 psi and that seemed to be the key.

So I just wasted probably a day's building time messing around with a back riveting set using (for my setup) too low of an air pressure for my gun. At 60 psi (which is a lot btw) I could set each rivet with about a 1/3 second burst of the gun. One bust and each rivet set just about right. I had to go back and hit a couple an extra bit but overall, it went much much faster at this pressure setting for me. That just left the very last rivet at the trailing edge of the skin to set which is a bit harder due to the bend of the skin. I messed up one or two of those but by now I'm an expert at removing these rivets.

So with the one side of the skin's stiffeners finally in place, I prepped and primed the remaining stiffeners and back riveted those in place without too much of an issue. Still a few tipped over but I was able to fix those or replace those as needed. That wrapped up the left elevator (for now) and it went back inside to the parts shelf.

Time to rinse and repeat this process for the right elevator in the next few build sessions.