Some of the rivets in the left spar have been bugging me. Some of them look like upside down mushrooms. I decided to remove and replace them. The only rivets that did this were some of the -11 size that I had sanded down from a -12. I'm wondering now if the heat generated from sanding them down on the belt sander may be the issue. I didn't have the same problem on the right spar (I used rivet cutters on the right spar). All the rivets I replaced came out clean.
I positioned the rib attach angles to the left spar using the #8 bolts through the capstrips. I also clecoed them to the vertical stiffeners. Then I started riveting them using the pneumatic squeezers where I could but for most of the rivets I used the gun. I set the -4 rivets first and then finished up by setting the -5 rivets.
One comment I would add is that Eric Newton’s recommendation in the Wings Manual to make the rib attach angels 5/8" x 5/8" is very helpful. I've read where others have had issues working with 1/2" x 1/2" angles and I can see why. The bigger angles prevented similar problems.
