I was thinking I might actually get done with the horizontal stabilizer tonight since I was ready to swap ends and get started with the right side. I should have known better. I modified my procedure a little bit after some lessons learned on the left side - namely even though the directions wait to attach the inboard ribs to the spar until you do all of the ribs together, that ended up being a nightmare to do it that way. So instead I riveted the inboard main rib and nose rib to the spar before putting the spar in the right skin. Those inboard rivets are horrible, but it definitely worked better this way. The rivets still look awful because of their large size (it's amazing how a rivet that is only 1/32" larger in diameter is so much harder to set than one size down) and difficulty fitting a bucking bar where it needs to go, but they're structurally sound and I'm just going to move on.
So off I went on my merry way, riveting nose ribs and the front spar in. With the nose ribs done and the spar started, I riveted that troublesome inboard main rib in place just to get the skin a little more solid. That's when I happened to see a call out on the plans that the instructions make no mention of. The instructions just say to rivet the main ribs in place. What they fail to mention is that on the top side of the inboard main rib and nose rib, there are holes that have to be left empty for attaching the fairing down the road! I saw this a row of rivets too late. Given that this was also my second horizontal stabilizer side, it meant that I had also missed that info for the left side that was "done." So instead of hammering away and finishing up with most of the stabilizer tonight, I spent a ridiculous amount of time drilling out rivets.
Regardless of the setback, I did get quit a bit done. I have the whole assembly flipped (left side done and right side now in the cradle) and am working on riveting the skin on to this other side. I still struggle with setting good rivets in hard to reach places, but little by little I'm discovering tricks to make it easier. Dialing in gun pressure to just the right level is key, and I think I've pretty well got it figured out for the sizes of rivets I've used at this point. Tomorrow I should be able to finish up riveting the front spar and main ribs in, then will move on to installing the rear spar.
I did another test of my primer sample to see if it's changed with a week of curing. It definitely has. At the 24 hour mark, very little pressure scratched all the way through the non-scuffed portion. At 6 days, there's a pretty noticeable difference. The non-scuffed (acid etch only) portion is still not as tough as the scuffed side, but much better than it was on day 1. The scuffed side is pretty solid at this point. While I could scratch through it with effort, just rubbing the tip of the awl across it just burnished the surface for the most part. Truth be told, I bet just acid etching would probably be fine for internal surfaces. The only downside is that most of the abuse to the primer comes when working with tools. The acid etch surface won't stand up to that as well. I'll probably continue to manually scuff along with the acid etch, but based on this test, I think I'll chill out with the effort a little bit. It's apparent that the primer will stick pretty well with minimal scuffing. The only areas on the structures that I'm seeing issues are on the edges of parts and where I've rubbed a metal tool against it. I always figured that would happen to a certain extent.
