Good bit of work done this afternoon and evening. With the bottom side of the skin riveted closed, it was time to finish the other side. There's one little portion of the top side that you do not rivet at this point as the hinge for the trim tab must be included in the riveting of that section, so other than that, the rest can be closed up. First things first, time to get some more RTV on the last of the skin stiffeners, the short ones nearest the inboard part of the elevator. With that goop in place I could proceed with riveting the skin on. I had a visitor this afternoon to help me out. Conner lives just a street away and is very interested in an aviation career and joining our EAA Chapter. He's already gotten to stop by my work and check out the jets that we fly so naturally he needed to stop over and see the RV-8 project. I coached him through setting a few rivets with the squeezer and he did great! Only problem was I forgot one of the rivets needed to be a longer 3-4 size so I set him up for failure lol. Totally my fault and I recognized it right away since it set so much shorter than than the surrounding rivets. This was out on the counterbalance skin area where there are multiple layers of sheeting needing to go together, really need to pay attention here as there are 3-3.5, 3-4 and even a few 3-4.5 sized flush rivets in this area. After dinner I finished the rest of the rivets in this area and started down the spar working my way around to the 705 rib. The hand squeezer makes it fairly easy and I find the lower weight of this tool vs. the pneumatic squeezer to be much less fatiguing so I tend to squeeze them all by hand if I can. My OCD really appreciates a long row of equally set shop heads! With that done I finished the bottom side where the skin joins the trim tab cutout spar. Since I decided to make a little riblet for the end of the elevator cutout, I also had those six rivets to set. Stupid me, I threw a 3-3.5 rivet in there because that's what all the other ones were only to remember that I used slightly thinner material to make that little riblet and needed to step down to a 3-3 rivet instead. I think I tried to squeeze 4 rivets before I realized why they were all tipping over. Dumb, dumb, dumb!!!! I just laugh at these kind of mistakes now as all they cost is time fortunately and the #3 rivets are easy to drill out. So after I drilled out 4 of those rivets I managed to set those 6 rivets as well as the two rivets adjacent to those that the plans call for the Mk-319-BS blind rivets. I could get to them with the no hole yoke that I have so I used a couple flush rivets instead. I also went back and drilled out a few other bad rivets from around the elevator. I had a long hard look at those two #4 rivets that join the elevator spar to the outer ribs where the counterbalance sits. I had to drive those a few days ago with a double offset rivet set and at the time was happy with the results. Now that I had everything pretty much together and had the elevator sitting upside down in the jig, I could see a slight gap between the head of those two rivets and the material they were set in. Had a bad feeling about these as I realized drilling these out and fixing them would not be easy now that the skins were riveted shut. I realized that maybe a few blind rivets here would have been a better idea. Perhaps Vans wants the strength of a universal head rivet instead of pop rivets? Either way I remember encountering this before on the horizontal stab and there is a spec in Section 5 of the manual that talks about this. I have attached pictures of that spec and what I found to document that thankfully both rivets still meet the spec. Good cause that was going to be a giant pain to get those out of there. One of those cases where you could end up doing more harm that good so I'm glad we don't have to go there! Last task for the night was to finish off the 6 remaining blind rivets using the Mk-319-BS pop rivets. I tried to insert one into the dimpled hole and it wouldn't go. Hmmm.... so I grabbed the drill with the #40 bit and give it a quick pass to make sure the paint wasn't interfering. It's fairly common to have to redrill a hole here and there as the primer adds just enough thickness to make the rivet not want to insert easily. So I tried the drill trick and still no luck. I pulled the calipers out and measured the shank of the rivet, 3/32" was the result. Hmmm.... checked the size of the #40 drill bit, 3/32"... What gives??? I switched the caliper to millimeters and sure enough, even though the inch fractional sizes are the same, they are not the same size as the rivet is a few thousands larger than the #40 drill bit. A quick check with Google and indeed, other builders have found this out as well and it turns out for this particular rivet, MK-319-BS, you do indeed drill and dimple for a #40 hole but then you need to enlarge the hole ever so slightly with a #33 drill bit. Of course I don't have a #33 size bit! Slightly defeated after an otherwise good day in the shop it was time to call it a night and order the #33 bit off of Amazon. Because I'm impatient and just want to get those 6 rivets set and move on to finishing the trim tab, I ordered enough junk on Amazon to have the drill bit here by lunchtime tomorrow. Jeff Bezos gets more of my money than he needs to once again.....