Not a lot to report today. Basically I dimpled everything except for the skins, which will require use of the C-frame. For the most part it was uneventful, except for some spots on the forward floor. On each outboard edge, where the lower longeron attaches, there are five spots that require flush rivets for clearance. One of these is at the aft end, which is easy to get to. The other four are right up next to the gear towers, presumably to provide a flush surface for the gear mounts. These are annoying to get to, because the gear tower and the gear weldment make access difficult.
There’s no way to get a squeezer onto the holes to dimple. There’s no room to use my vise-grip dimpler. The skin is way too thick for the pop-rivet dimple tool to work. I eventually worked out a method using the pop rivet dimples dies and a squeezer with a no-hole yoke (to get into the tight area). The resulting dimples aren’t great, but are acceptable. This is a spot where I would have been better served to depart from the instructions and countersink the flow instead of dimpling. The material is plenty thick for countersinking, and in fact the holes at the aft end of the floor, where it mates with the center section bulkheads, are countersunk for flush rivets. Unfortunately, in the case of these holes, I already countersunk the lower longerons at those locations, so my choices were to either dimple the floor or replace the longerons. Oh well.
Next up, I get to roll some skin edges and then do a lot of dimpling with the C-frame, followed by priming. Which reminds me, I need to restock on primer. Hopefully the weather next weekend is good, so I can get some priming done. It should be especially fun to clean and prep the 16’ longerons…