Bending Aluminum: Looking for tip

[Phil]

Everyone has a builder moment where they slap themselves as say "Why did I do that?" This afternoon I had one.

I'm working on the HS and was in the process of removing a rivet. In the process of punching it out of the hole, I bent the (thinner) flange on the back side.

I tried to bend it back, but obviously the spring-back keeps me from getting a tight fit with the spar. This has resulted in an 1/8" gap between the rib flange & the spar.

Short of some major disassembly to replace the rib, I think I have the following options.

1) Find a way to bend it more. (That's the tip I'm hoping someone knows.)
2) Place a shim between the flange and spar and rivet through it.
3) Try and find some creative way to clamp it to the spar while setting the rivet.

Thoughts? How have some of you fixed this issue?

Phil

[grjtucson]

Glue an o-ring or thin slice of rubber tubing to your bucking bar. Shoot and buck rivet using that ring over the top of the "shop head to be." You'll get a good shop head and the ring will have snugged up the bent flange while bucking.

George

[rzbill]

George is right on. This will not be the only time you will run into a recalcitrant flange that needs some coercion to sit flat. I have a 1/8" thick rubber washer for the purpose. Bang away just long enough to clinch the pieces and then the rubber tool can be removed to finish the shop head.

[Dave62]

Not being an RV builder but one who has driven a lot of rivits...I would just put the manufactrued head on the rib side and the shop head on the spar side and push the rib tab up with the rivit gun before setting the rivit.
Dave (Swift driver)

[Phil]

Thanks for the tips so far. Intrested in hearing more, I might learn a few things.

Originally Posted by Dave62

Not being an RV builder but one who has driven a lot of rivits...I would just put the manufactrued head on the rib side and the shop head on the spar side and push the rib tab up with the rivit gun before setting the rivit.
Dave (Swift driver)

I thought about that too, but there's less than 5 inches of clearance for the rivet gun. So you can't get the manufactured head on that side.

[Mel]

Use a pulled rivet and you can hold the tab down while pulling it.

Use squeezer with longeron yoke.

[Phil]

Originally Posted by Mel

Use a pulled rivet and you can hold the tab down while pulling it.

Use squeezer with longeron yoke.

Speaking of that Mel, I've been looking for a chart that cross references Solid Rivets with a pulled Rivet equivelant. Do you know where I can find one?

Thanks,
Phil

[Mel]

All you need is the diameter and grip length. Unless you're talking about strength. If you're talking strength, just compare the specs. I don't know of a direct cross reference.

[Phil]

I did come up with another neat little trick.

Even after bending the flange back to shape (and if you look closely at the photos) you could still see a little wave in it.

I took my 1/8" pop rivet dimpler and reversed the dies so that the flat side of the die was against the flange. I gave it a couple of cranks and presto! A perfectly flat flange.

Now that the wave is out of it, the flange sits much flatter. I'm guessing the gap is around 1/16" or less now. It'll be much easier to get it tight now.

So don't forget about your dimple dies. They work the other way around too!

[RScott]

Another way is to drive the rivet only slightly, just enough to expand it snug in the hole. Then put the bucking bar on the flange beside the rivet and give the manufactured head a couple light taps with the gun. That will pull the flange against with the spar and with the rivet snug in the hole, it will hold it.

Now, in your particular case, this technique probably wouldn't work, because the flange was distorted so much. But if there was just a little gap, it will work fine. Glad the pop rivet dimpler worked.