July 17th, 2007
HS Priming and Rivet HS Spars
I will probably dedicate a page to priming and move some of this text down the road after I have dome some more priming and gain experience with the products.
I finally made up my mind on the priming issue. I did a lot of research and asked a lot of questions to other builders. In the beginning, I was set on using a 2 part epoxy type primer. Many builders start out their projects doing a lot of priming and use the whole MEK, Alodine and epoxy based priming methods. But as their projects progressed, they shifted to doing less priming and many told me if they were to do it again they would use the rattle can self etching primer.
Here is what I ended up using. First, I clean all the parts with the PPG DX533 using a 1:3 ratio with water. I mix it up in the Home Depot spray bottle. I don't spend a lot of time at this. I follow the PPG instructions and let it sit on the parts for 1-3 minutes. Then I thoroughly rinse off the parts with water from the garden hose. I lay the parts out in the sun and they dry quickly.
Once the parts are completely dry, I spray them with the SEM self etching primer and flip them over after about a 5 minute flash time. Repeat on the reverse. I then give the parts about a hour before I rivet together.
Here is a simple priming table I built from a couple 2x4's and some wire roll material that I found at Home Depot. Chicken wire would work as well.
Here is what the parts look like after priming.
The ribs after priming. I was able to complete all the priming in about a hour.
Ok. Time to rivet the rear HS spar. This is all pretty easy stuff. I used my pneumatic squeezer for all of this.
The first row of rivets is done.
These 8 rivets is where the HS-413 brackets attach. The plans call for AN470AD4-5 rivets but in my opinion they are too long to get a good looking shop head. I substituted AN470AD4-4 in their place. This made for a better looking shop head. The rivet on the lower right is a 4-5 and you can see it sticks out a little too much. (It has not been set yet)
Another view showing how long the 4-5 is. The rivet on the lower right has not been set.
Here is a shot of where the bearing bracket is bolted to the spar. The instructions call to torque the bolts. I do not have a torque wrench so I need to pick one up and come back to these later.
Here is the completed rear spar. I did not prime the parts that were powder coated.
The front spar where the HS-714 & HS-710 attach. Notice the center 4 holes are dimpled for the flush mount rivets. When I built this I was wondering which direction to set the rivets. My shop heads are facing the rear of the spar. I made a quick call to Van's and the confirmed that it doesn't matter which way the rivets face. Sometimes convenience dictates which way the rivet gets installed. With that said, in some cases, it does matter which way they are installed and the manual or plans should show that.
The other side you can see my markings showed up through the primer.
The front 404 and 405 ribs were a real pain to get riveted in place. I had the drill out my first rivet here. At first I was trying to make the squeezer work but the rivets were squashed to one side. I switched tot he rivet gun and things went much better. If you bend the ribs out of the way like the instructions say it will be easier.
Completed 404 to spar to 405 assembly. These 404 & 405 ribs are a real pain for a lot of builders.
Brian pointed out to me that I shouldn't have put rivets in the 4 holes where the HS is mounted to the fuselage. I could have waited to drill them out when I mounted the HS but I decided to drill them now and not worry about them later. You can see the four holes after the rivets were removed. No harm done I guess. The pictures show 7/18 because it is after 1am by now.