Yesterday and today I riveted the bottom j-channel to the side skin. I also riveted the side skins to the bulkheads where the skin curves inwards toward the bottom skin. Everything went well, although I did remove a rivet when it cleaved over.
Since I’m bucking these rivets, and doing it by myself, I can’t actually see the shop head of the rivet. So I came up with a way to make sure the bucking bar is at the correct angle, since the j-channel is attached to the side skin at a point where it’s already starting to curve inwards to join the bottom skin. By putting some clecos in “backwards” and tying a string between them, I had an angle gauge for the bucking bar. Most of the rivets came out nicely.
Next, I’m going to attempt to back-rivet the remaining rivets on the bottom, starting with the last rivets on the curved surface of the side skins. I couldn’t quite reach these with the gun and bucking bar, so I’m hoping to back-rivet them, as other builders have done.