I tackled the trailing edge riveting a little differently this time around. The "normal" way of doing it is to tape or proseal the wedge in place, then partially set the rivets (just enough to swell and stay put) using a back rivet set, then flip everything over and use a mushroom set and the back rivet plate to finish setting the rivets. This works fine, but it can be kind of difficult to keep the edge straight and flat, and requires some finesse with the back rivet set to keep from dinging the skin since you have to start vertical and then angle it to match the skin angle. Instead of using the back rivet set, I decided to use the squeezer to do the initial partial set of the rivets. Because I didn't need the back rivet plate at this first stage using this method, it meant I could leave clecos in the trailing edge to keep the wave from causing a headache. I slid the flap off the edge of the bench just enough to allow me to get the squeezer in position. To try to protect from a wavy edge even more, I put a board and weights on the flap to keep it all flat to the table while I riveted.
Van's calls out 3-3 rivets for the trailing edge, but those seemed short to me. I used 3-3.5s instead, which were maybe a little on the long side, but still worked better than the 3-3s would have I think. I set the squeezer to just squeeze the rivets to the point where the rivet set would almost touch the skin at it's widest angle, which left quite a bit of the rivet still protruding. Because the clecos were holding everything in place and the weights were keeping it flat, I just went down the line with the squeezer. When doing this the typical way, you have to bounce back and forth every 6-10 rivets or so to keep from creating a hook in the trailing edge by doing too many rivets in one place at once.
Once done with squeezing, I flipped everything over and finished by using the mushroom set and back rivet plate. The shop head (that was partially set) went down against the back rivet plate, and the mushroom set hit the manufactured head. It didn't take much to set the rivets the remainder of the way. In the end, the edge turned out amazingly straight with no noticeable wave in it. It's kind of hard to take a picture to show the edge. It kind of looks like a transparent flap here.
Here's what the shop heads look like using this technique. Very clean and flat. I probably could have gotten away with the smaller 3-3 rivets, but I think I'll still use 3-3.5s on the other flap.
So the left flap is largely done now. I still have a couple of rivets to set on the end ribs, but I'm waiting for a new tool to get here to do those. It's too tight for the squeezer, and I was told that a great tool to have for awkward places is the parallel jaw Knipex pliers. Apparently they work great for squeezing size 3 rivets in places where bucking isn't ideal and a squeezer is too big.
On to the right flap again! Everything is fit and ready for the assembly, so that means lots and lots of deburring needs to be done.
