Father’s day was this weekend and my lovely wife gave me all weekend to work on the plane (in addition to some other great gifts). So I got to riveting the rudder halves together. I used the 3M VHB tape method described in section 5 instead of using ProSeal to bond the trailing edge. This seemed less messy and others have had good results, plus I was able to get VHB tape locally.
Some good lessons learned along the way – particularly around slowing down to pay closer attention. When riveting together the stiffeners and shear clips, blind rivets are used since there isn’t really enough room to get a rivet gun down inside the rudder trailing edge. Starting at the bottom, one skin is held back to give access and the bottom stiffeners are blind riveted to each other and the shear clip. You then work up toward the top, doing each successive set. The plans specifically call out to pay close attention to the orientation of the 3 parts to ensure the shear clip sits on top of the stiffener. This is where things went sideways. The first few went well, but somewhere along the way I decided I wanted to rivet one stiffener below and one above the clip.
I ended up doing the top 3 incorrectly and had to drill out the rivets. And let me tell you, drilling out blind rivets is a **BITCH**. The steel mandrel causes the twist drill to walk to one side or the other and the aluminum rivet doesn’t offer enough resistance to prevent the walk. I did some research which suggested driving the mandrel out the back using a punch, but I couldn’t get enough clearance to back the stiffeners and shear clip with something solid to prevent damage. Even if I could have backed up the parts, I doubt I’d have been able to get a hammer in there to drive the punch with enough force to push the mandrel out. What worked for me was to very slowly drill the manufactured head with a small twist drill only slightly larger than the hole from the mandrel until I felt slight resistance as the bit reached the mandrel. Then step up in the smallest increments I could until the head broke off. I then backed the parts with a small piece of wood cut to fit just up against the assembly and used a spring loaded automatic center punch to knock the shop head end out. It was tedious but I was able to successfully get the rivets out without expanding the hole or damaging the parts. As luck would have it, it wasn’t enough to just drill out the rivets for the piece that was on the wrong side, I had to do all 4 rivets common between the shear clip and stiffeners so I could pull out the entire shear clip and orient it correctly. All it, it was 12 rivets plus one other rivet I had pulled before realizing my mistake – and 3.5 hours lost between researching, practicing on scrap, and actually doing the repair. All because I “saved” a few seconds by going quickly. Lesson learned!
I don’t have any pictures, and I don’t think I’ll post the video of this one since it consists mostly of me stamping around like a child being told no and cursing a lot. Take my word for it, slow down and do it right the 1st time. It will save so much time and more importantly headache in the end.