Only a third done after 2 hours' work, but am slowly riveting the spar to the top skin. Might be more accurate to describe this a "riveting patiently", so that hopefully I don't bung up the skin with the rivet gun.
A good share of the time went into figuring how to clamp the skin open without putting another kink in it.
You can see in the photos below how I went about clamping things; and it's worth noting that even after all this I was operating the bucking bar by feel. Only one rivet drilled out so far on the spar, so crossing my fingers.
And finally there's the obligatory photo of an endless row of rivets. Remember that there is a second one of these coming up!
Total Time these 2 days: 2 hours.