221 hours on the hobbs. Got to Pound some Rivets tonight!

Right side Rudder stiffeners almost entirely back riveted into place. got all of them except for the ones closest to the trailing edge where the bend is located. I need to contact some of my fellow RV-8 builders to find out how they managed to pound on these rivets. I have a feeling that most folks just gently bend the other half of the skin out of the way, and then apply sufficient pressure with the back rivet set to force the skin and the stiffener to lie flat onto the back rivet plate. If you don't force the skin to lay down flat you won't set a good rivet.

Anyway, after back riveting some test pieces yesterday, one on the work bench and one on the concrete garage floor, I too experienced better results with the rivets that were set from the plate laying on the concrete floor instead of the workbench. This first pic shows the spot I chose to do the dirty work. Two light blankets on either side of the polished steel back rivet plate, and the rudder skin in position:

The next shot shows the plate, my rivet guage, and the rivet gun with the back rivet set installed. The process was basically to set one stiffener at a time into position, sliding the stiffener holes over the protruding rivets, and then get down on my hands and knees, position the rivet gun over each proturding rivet, and squeeze the trigger - wash, rinse repeat.

Even though I had to get down on my hands and knees to do this, I have to say that I really liked the results I got. Here is a pic showing the line of rivets on one of the stiffeners - very nice looking if I do say so myself. Remember, you can click on the pic to make it bigger.

This next one is a little dark, but shows a cross section view of several stiffeners after they have been back riveted. If you look at the very top left of this pic you can just see one of the trailing edge rivets still protruding through the stiffener that has not been set yet. Other than being on the hands and knees, this process was rather enjoyable. After a little practice on some test pieces, there is really not much to it. Just have to remember to turn the air pressure way down for this. It takes a lot less pressure to back rivet than it does doing it the conventional way.

And finally the almost-completed right side of the rudder stiffeners - Not bad for an hour's worth of work.  I will finish the left side tomorrow.Then it will be time for the big bend to form the crisp straight trailing edge of the rudder. Sport Air RV class is also coming up this weekend - I can hardly wait!