I have my seat ribs clecoed to the center bottom skin. It's an exciting moment. But before I try to rivet them together, I am wondering if anyone has any tips on techniques that do or do not work. It's an awkward piece and obviously an important one.
I'm waiting for my helper to come back to finish up the top skins on the tailcone, so I will just work on other sections until he finds time to come over. There is always something to work on, even if it's usually deburring and priming.Don't try to do it alone! It's easy with a helper.
What worked for me is building up the fuselage from the firewall back on a rotisserie.
I was not happy with my backriveting work on the AD4 rivets from the aft gear brace to the center bottom skin. So I'm probably a little gun-shy about backriveting the ribs to it, but I suppose if I go slow it's not such a bad deal. I'll still hope my buddy can come help, though. Just a second set of eyes can be helpful on some of this stuff.
The ribs are all AD3's, and of course I've got experience with those from the rudder, elevators, and several other places. The AD4's just seemed not to want to behave for some reason, as several ended up with their manufactured heads sitting proud of the skin. I think that, as long as I take my time, I should be okay to backrivet the ribs. But I wanted to post and ask for tips in case there are better techniques or just tricks to it to get a good result when you have the rib upper flange in the way and some tight alignments (a few rivets will take a little tapping to sit flush into the skin before I set them).Not knowing what your back riveting issues were with the AD4's, I would just note that the rib rivets are all, or mostly all (I don't remember), AD3's. They are much easier to deal with and should be in your ballpark of experience as back riveting AD3's is called out in the plans in several areas on the airplane.
It's a good technique to get comfortable with, but I don't want to talk you into something that you're not comfortable with now.
I always use rivet tape, whether backriveting or not. I love that stuff. But tape won't hold a rivet in place if it's not sitting flat on the backrivet plate and you hit it with a rivet gun.Have you tried using riveting tape? It helps keep rivets in holes because if you get some heads sitting proud then the heads were not flush on the back rivet plate.
Don't try to do it alone! It's easy with a helper.
What worked for me is building up the fuselage from the firewall back on a rotisserie.
I had help when I attached the F-01484 Center Bottom Skin. Stood it up on end and went to town.
Back-riveting that skin would indeed be an elegant approach.
For the ribs' forward and aft flanges, I did that solo with the double offset rivet set and "Mr. T" (a tungsten bucking bar, shown below).
Mr. T. Currently available from Brown Tool.
A wrap of duct tape around the gun prevented the insidious spinning of the set. Masking tape on the rivet heads helps provide friction and mitigate smilies.