I applied some primer to the countersunk holes on the flanges of the spars and stringers. This is to provide a barrier between the spars and the dimpled skin where the skin will sit inside the countersunk hole. I sprayed some rattle-can primer into a plastic cup, then used a cotton bud to apply it to the holes. The primer color is olive drab, but it will be completely covered so I’m not worried about it not matching the white primer I used on the rest of the parts.
Then I inserted the forward spar into the skins, and riveted the spar to the nose ribs, joining the whole forward spar and rib assembly to the skins. I couldn’t get my pneumatic pop rivet tool into the rather narrow gap between ribs, so I used my hand squeezer to set the rivets. Everything came out nicely.
Here’s the clecoed skins, ready for the next step of setting the 600 odd rivets.
I also applied some thread paint to the torqued bolts on the rear spar. This will provide a visual reference to identify if the nuts ever loosen up for any reason.