Tip: Dealing with a bent flange

[Phil]

Today I was tapping out some rivets with my wife and I usually try to back the flange up with something like a 1/4" socket. At least it's something to hold the flange in place and allow the rivet to tap out cleanly into the hollow section of the socket.

That works great!

Except for when your wife backs up the wrong rivet.

Tap Tap BEND!

Sure enough the flange of a bulk head bent and quite a bit too. I tried to bend it back in place but it was just too springy and the bend wasn't going back.

Here's my fix that's currently curing in the garage.

I mixed up some Metalset A4 (JB Weld will do the same) and pushed some between the flange and the skin. The goal is to glue the flange down long enough to set the rivet. But the real trick is finding a way to pull the flange down tight.

I took a pop-rivet dimpler and squeezed it until the flange pulled up tight against the skin. Then I used a clamp to hold pressure on the rivet puller.

This contraption is currently hanging out the side of my airplane and the Epoxy should cure overnight.

Also I dipped the dimple die and nail into mold release to hopefully help with its removal. I'm sure hairspray or something similar would have worked too.

Just thought I'd pass this idea along.

Phil

[Lionclaw]

Whenever I run into a tab that won't lay down i fold a paper towel a few times and tape it to the end of the bucking bar so that it sits next to the rivet, but not on top of it. The paper towel is firm enough to push the tab in place, but squishy enough to be compressed for a few hits of the rivet gun.

Hope this makes sense!

[davcor]

Find a faucet repair kit with flat hard rubber washers. Pick one about 1/2" diameter with screw hole. Note that some are thicker than others, you may need to try different thicknesses to get the right setup.

Back at the project, put your rivet (it may need to be a little longer than originally specified) in the hole and place the washer over the rivet on the inside. The shop side if the rivet should be a little short of flush with the rubber washer.

Next bucking bar against the washer. Press with your rivet gun and the bucking bar at the same time. Use enough pressure on the washer side to "close" the (flange) gap. This will bring the shop end of the rivet close enough to the bucking bar so when you shoot, the washer will compress a little and let the bucking bar do it's job.

Next give it a few hits. Remove the washer and check the results, you'll see a partially set rivet holding the gap closed. Hit it a few more times to finalize and move on.

I hope that makes sense. I've used this technique in a few places and it worked well.

Good luck

[Phil]

Yeah I thought about that too, but my wife (helper) is out of town and I couldn't hold everything in place and still get to the rivet gun..

So I opted to glue it and free up an extra set of hands.

[David-aviator]

When I saw the title "...bent flange" I immediately thought you were dealing with an engine prop attach flange and thought oh, oh, another air boat crank shaft. Glad to read that was not the case.

By comparison, your bent flange is almost a total non-event. I had one or two in that area and got them down somehow but can't remember just how it was done. The information is buried somewhere on my brain's hard drive two or three layers down and in a couple days it may pop up. Seems like the more you know, the less you remember...what's needed is a better search engine.

[Phil]

[quote=David-aviator;290765]When I saw the title "...bent flange" I immediately thought you were dealing with an engine prop attach flange and thought oh, oh, another air boat crank shaft. Glad to read that was not the case.
QUOTE]

I just got off the water in Galvestion Bay. Beautiful day, but the fish aren't biting. When I pulled the boat out of the water, there was an airboat launching with a Turbo Charged IO-540. I should have snapped some pics, but forgot to.

[jsharkey]

....wives, or other helpers, but wives especially never back up anything wrong. You must have communicated the wrong rivet

[mannanj]

Another way to get the flange to lay flat with the skin is to insert the rivet through the skin and flange, lightly tap the rivet against the bucking bar to slightly swell it out. You then lay the bucking bar against the flange and lightly tap the rivet again. The flange should slide up against the skin and stay there. You may have to swell the rivet just a little more if the flange won't stay in place.

This technique will only work if the if the prescribed rivet is long enough to go through both the skin and the bent flange. You should be able to manually bend the skin close enough to do this trick tho.

Finish driving the rivet.

If in doubt, practice on some scrap first.

[rdamazio]

Originally Posted by mannanj

Another way to get the flange to lay flat with the skin is to insert the rivet through the skin and flange, lightly tap the rivet against the bucking bar to slightly swell it out. You then lay the bucking bar against the flange and lightly tap the rivet again. The flange should slide up against the skin and stay there. You may have to swell the rivet just a little more if the flange won't stay in place.

This technique will only work if the if the prescribed rivet is long enough to go through both the skin and the bent flange. You should be able to manually bend the skin close enough to do this trick tho.

Finish driving the rivet.

If in doubt, practice on some scrap first.

Thank you!! Just saved my horizontal stabilizer from having hundreds of rivets removed to fix a mistake on one small tab your technique worked great.

[wirejock]

Here's a cheap easy tip my mentor showed me.

Windshield washer hose trick.
Buy a foot of the two smallest. One fits #3, the other #4.
Cut a small piecce off just a tad longer than the rivet shank.
Place it over the rivet shank then press with the bar.
It holds parts together as you set the rivet and comprosses so it won't effect the rivet setting.
Once the rivet is set enough to hold, remove the hose and fully set the rivet.
When it gets mushed, cut another.