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First skin rivet

rweinberg

I'm New Here
Hi all.

Starting to rivet the skin to the vertical stabilizer on my RV-7 project.

I noticed after riveting the first rivet that the flange is not sitting flush. This is the vs-702 vs-707 intersection.

Is this generally acceptable here or should I remove this rivet and fix before continuing?

Interested in your thoughts!
 

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First of many

I think the structure is much stronger when all the pieces are pulled tightly together. Easier said than done for sure. There are many of those little tabs on the build. Many of them are in very difficult places to buck the rivets. It is easy enough to drill that rivet out before you start riveting the skin on. Maybe bend the tab a little less than 90 degrees so it will sit flush against the skin when it is all clamped together. I think I used a couple of pull rivets to pull those tabs tight on my RV.
 
The usual approach to this problem is to slip an O ring or very short piece of rubber tubing around the rivet tail before riveting. The O ring or tubing should be small enough so that it doesn’t interfere with setting the rivet, but thick or long enough that when squeezed between the work and the bucking bar it will force the pieces together before the rivet sets.
As to this one, it’s a judgement call. I’d probably build on.
 
I don't think this would cause a problem. With that being said, you're early in the build and you'll run into this again. I'd fix it so you learn how to deal with it going forward. It will be very easy to drill the rivet out and redo it. The rubber tubing suggestion above works pretty good. You can use a small piece of vacuum tube, or rubber primer line. Whatever tubing will slide over the rivet tail.
 
The tubing that others have mentioned works well. I use silicone rubber tubing as it is easy to slip on and doesn't leave a black mark like some other rubber can.

The shop head in the photo also looks under-set or bent over so I would replace it as it's very easy to do so at this stage.
 
Careful when drilling out the rivet not to make the hole bigger. As the hole gets bigger the rivets are harder to set correctly . I would try with a drill bit smaller than #40 and once drilled through try to pull the rivet out. Take your time for the first ones.
 
You will find many places where a shim is needed. The most critical are skins to bulkhead rivets where the bulkhead is curving, like the top skin on a tail cone. This is how you prevent flat spots in the skin.

The rule is if you can fit a shim between the rib/bulkhead and the skin, it needs a shim. I use perhaps 30 or so in a build.

I make the out of 3/4”x3/4” scrap 0.032” and 0.025” aluminum. Drill and dimple.

Carl
 
Rivet removal

Just in case...
1. Center punch the factory head
2. Using a bit 10 smaller than the hole, drill. Drift toward center as needed. No need to drill all the way through but past the parts helps relieve tension.
3. Use a bit one size smaller than the hole. Install a drill bit stop so only enough bit is showing to penetrate the factory head and no deeper. Drill the head.
4. Remove the bit from the drill. Flip it over. Insert in the hole. Snap the head off.
5. Tap the shank out with a drift punch or a modified auto punch. However, if light taps won't push it out, DO NOT HIT HARDER. It will distort substructure. Place a bucking bar underneath to support the structure. A set of home made bars is handy for this. See my blog (below) for a Kitplanes tip.
Do it like this and you'll never hit an edge and make an egg shaped hole.
 
FYI- regardless of what you decide to do in this case, industry standard guidance is that you generally shouldn't be able to slip a .002" feeler gauge between the stack all the way to the rivet shank.
 
Thanks for the replies all!

I removed the rivet, bought some 1/4" fuel line from home depot, and tried that method. Now it is nice and tight. :)
 
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