I could use some advice on this. This is a picture of the right side of my RV-12 where the lower fiberglass cowling (on the right) meets the aluminum fuselage structure (on the left). The lower of the two hinge pins on the lower cowling runs down the center of the photo.
A while ago, I started noticing some "smoky" residue streaming rearwards from the hinge line. You can clearly see some of this residue at the top of the photo, above the black paint stripe, but it extends along much of the length of the hinge pin. Originally, I thought this was caused by the pin vibrating against the hinges and I didn't worry too much about it.
More recently, the paint on top of the flush squeezed rivets securing the hinge to the fiberglass has started cracking around the rivet heads. You can see this in the lower right side of the photo. This makes me think the rivets are loose and they may in fact be the cause of the residue. I likely under-sqeezed them during assembly in fear of damaging the fiberglass.
I haven't taken the cowling off yet to investigate, but I'm wondering what the best remedy might be...?
1. Re-squeeze the existing rivets and hope that tightens everything up?
2. Drill the rivets out and replace them with the same rivet?
3. Drill them out and replace with a larger, round-head rivet? (I figure a round head rivet would provide better compression)
4. Drill them out and replace with LP4-3? This is what I'm leaning towards. Any reason not to use a pulled rivet here?
My tentative plan is to drill out each rivet, open the hole to #30, and cleco before moving to the next rivet. Then remove the hinge, deburr, and clean up/scuff the mating fiberglass. Then smear some epoxy on the fiberglass and hinge, cleco the assembly together, and re-mount the cowling while the epoxy cures. Finally chase the holes with a drill and rivet with LP4-3.
Comments? Other suggestions?