Wings 26, Total 489 - Left Wing Nut Plates Riveted, Right Wing in Progress

So I got some Q tips today - found some tapered ones with more of a pointy tip to them that actually applied primer to the exposed metal of the countersunk holes pretty well. I just shot a small amount of 7220 etching primer into a mixing cup and used the Q Tips to apply the primer to the metal around each hole. I didn't do the neatest job of applying the primer, but it's done. It was easy to apply the primer to the rivet holes using the tapered tip of the Q tip. I just quickly inserted the tip into each hole and enogh primer was retained on the swap to fill each hole with primer, so that part of it went fairly quick.


With the primer applied and dried, it was finally time to rivet the nut plates to each spar flange. Here are some shots of the front and back sides...

I ended up using a combination of the hand squeezer with the no hole yoke and a 1/2 inch flat set, and the pneumatic squeezer with the flange yoke, using the 3/8 inch wide flat set on the shop head side, and the 1/2 inch wide flat set with the  on the manufactured head side to set the rivets. I had read a post on someones builders log, sorry I don't remember who, that indicated that they had better results setting the rivets using the no hole yoke, and I would say that I pretty much have to agree with that. The main reason is that the inboard nut plates are all positioned at angles to each other and the spar, due to the lack of space to allow them to be oriented in a straight line. This is because of the close proximity of the extra ribs in that location for the wing walk area where everyone steps on the wing to enter the cockpit/cabin of the aircraft.

I could not reach the bottom rivet holes of these nut plates very well with the flange yoke, but the no hole yoke and the hand squeezer worked out fine. You have to be careful that you don't catch an edge of the nut plate and damage or deform it somehow. Of course, the other objective was to make certain that all the rivet are set so that the manufactired head is flush with the spar flange. They need to be flush because the wing skins and tank skins need to sit flat over the top of the spar flange. If they are not flush to the spar flange then they could start wearing cracks in the tank skins, which would not be a good thing.

First it took about 15-20 minutes just to cleco all the nut plates in place:

This next shot turned out to be a wierd photo due to reflections off of the face of the no hole yoke, but if you study it long enough you can see how things are positioned. Attempting to show the no hole yoke and the hand squeezer in position for attempting to the rivet one of the bottom rivets of one of the angled nut plates at the root that I mentioned earlier. You had to hold the yoke at an angle to avoid catching the screw shaft of the nut plate as you squeeze the rivets. There is not much room to play with, and I found out that I really needed to continue to grind down more of my yokes to create a bit more clearance for situations like this that I am sure I will continue to encounter in other parts of the build yet to come.

And the final product for the left wing spar:

the murky mess on the left side of the above pic is some of the primer mess that I made. I only ended up needing to drill out two rivets where I did not ahve the small 3/8 inch wide flat set lined up quite right, and I ended up smashing only about half of the rivet shaft. Drilling them out was a non-event. There are some manufactured heads that ended up sitting a bit to proud of the surface for my liking - most likely due to too much primer in the hole. I will evaluate and replace thosr ivets as necessary tomorrow, and get to work on the right wing spar as well. Nice to be riveting again, especially on the larger wing parts.

This exercise also gave me the opportunity to make friends with the pneumatic squeezer again. You know, that 10 pound heavy hunk of metal that is supposed to make riveting go much faster. Well, the reality I have experienced is that yes, you can generally slam rivets a bit faster than with the manual squeezer or bucking bar and rivet gun, but there is a cost, and that cost is manifested in the fatigue that it creates over your entire body during long rivet runs. So, once again, I guess you pick your poison - use the tool that will cause fatigue from all the repetitive manual squeezing you have to do with the manual squeezer, or become fatigued after setting a few more rivets with the pneumatic beast. The other thing I am finding is that you really need to have a lot more clearance both near the rivet and all around it in order to use that air slammer tool. There are so many tight fit areas where after clecos and clamps are in place, you just can't use the darn thing in those areas because it is too damn wide and heavy. The hand squeezer seems to take care of most of those issues. So if you have both tools to work with, you are pretty much set.