[RidiculousM]

I slipped and fell *** first on the aft corner of the F-827-1 left lower bottom skin. This is the skin that will overlap and be screwed to the left wing on my RV-8.

This did two things, first, it put a pretty good crease on the rivet line, where the red arrows are, it actually stretched and distorted six of the rivets, that's why I removed them. Second, it created an upward bow in the skin along the blue dotted line when it folded over the edge of the fuselage stand.

I'm wondering if I could tap some of it out using a rivet gun and a wood block.

Has anybody replaced one of these skins before?

I know in the end I can primer and fill to fade some of it out but I prefer to not fill rivet heads so any ideas, suggestions, tips would be great.

Thanks,
Mike

 

[Kyle Boatright]

Ouch. Sorry that happened.

IMO, most "cures" I can think of are worse than the initial problem.

I'd get a pair of seaming pliars (or clamp the piece between wood blocks) and try and persuade it as straight as possible. Then I'd replace the rivets and move on, knowing that the "wave" is on the underside of the aircraft and the only person who'll ever see it is the guy who cleans the belly.

Hopefully someone will come along with a better idea that doesn't involve replacing the skin.

 

[rvbuilder2002]

A crease occurs in a specific spot because that is where the bending load became concentrated. In this case right along the rivets.

With proper application of a reverse bending load, it can often be 90%+ removed. Unfortunately, improper application of the reverse bend can make it worse.

If it were me working on it, I would remove more of the rivets to allow for inserting a temp shim between the skin and sub structure. This is needed to allow for the spring back that you need to over come to get a bend to happen (the amount you have to over bend and have it spring back to where you want it).

The edge of the shim should have a shape that matches the unwanted bend line. If it is relatively straight, along the rivets, then the edge of the shim can be straight.
The edge of the shim you are going to be bending against also needs some radius to avoid putting a sharp crease in the skin as it bends in the reverse direction against the shim.
If the radius of the bend/crease is not constant (typical) then the radius in the shim should vary in a similar way. A rough approximation would be to double the radius (at any given point) of the bend you are trying to remove.

Put the shim in place and start massaging with your fingers. Regularly move the shim inboard or out board slightly so you are not always concentrating the bend in just one single spot.

Often times the bend is slightly different around the rivets because the skin is restrained at those points, with it more flexible in between. Many times I have removed that by clamping dimple dies on the skin with a hand squeezer and then massage the skin around the dies to get the reverse bend that I want.

Using these techniques, I have removed, many times what looked like seriously bad bends and kinks to where they are invisible after a little bit of filler primer during final paint. I do have quite a few years of practice, but it is something that anyone can learn. It might be a good idea to practice on a simulation first though, to get a feel for it.

Let us know how it goes.

 

[RV8Squaz]

In addition to those good techniques already mentioned, you could try to get a hold of one those paintless dent repair guys that fix hail damage on cars. Those guys do amazing work and they are usually pretty reasonable. A lot them are used to working with aluminum since aluminum is being used on cars more nowadays. They did some incredible work on my plane after some hail damage.

And finally, you can replace the skin if need be. When my RV-8 was upside down just about ready to come out of the jig, the hose fitting separated from the hose at 125 psi and put a major outward dent on the right forward side skin. This skin is complicated to replace due to the gear towers. Yet the pre-punched skin made it a non-event. All of the holes lined up perfectly. Just be extra careful and be patient drilling out all of those rivets.

I hope this helps and gives you some options.

Jerry Esquenazi
RV-8 N84JE

 

[RidiculousM]

Thanks for the very useful replies! Scott, I'm going to try your method and feel that will help out the situation a lot. I will post an update this weekend as to how it turned out. Jerry, your story sounds even more frustrating then mine! Glad it worked out for ya. I think I will be able to straighten it out enough to save it. But its good to know replacing it is a fairly straight forward option. I did talk to my local dent repair guy awhile ago about something else and he said no way to aluminum.

Thanks again for the help.

Mike