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structural adhesives instead of rivets

1

1bigdog

Well Known Member
I've done a terrible thing to one of the fuse skins. After I flatten it best I can the plan is to back it with a doubler.
Is it permissible to use a structural adhesive such as Loctite's EA 9017 or proseal in place of rivets. The dented area doesn't go through but it's dented/stretched enough I don't want to just ignore it, so that's why the doubler.
There is no useful mention of structural adhesives for 2024-T3 in AC43.13 so if anyone has other resources I could look at please let me know.
It's in a highly visible area on what will be a polished surface so I'm hoping to avoid the rivets.

Thanks for the guidance.
 
The short answer is, absolutely not.

And that's from an engineer who is both gluing and riveting his fuselage together. While I don't know the EA 9017, the Pro Seal is clearly not a structural glue. To properly make a structural joint takes considerable prep, the right glue, and even then, how do you know what you have? Unless you do a whole series of joint-specific tests, and compare the strengths achieved to rivets, you're just fooling yourself.

Even on my plane, the parts that are glued, are also riveted. The glue is not only not needed, it makes repairs much harder.

Don't even consider it.

Dave
 
So the dented area you are trying to fix is skin damage between any underlying structure? If you are considering repairing damage that involves skin attachment to a rib, or any other structural member, I would say that adhesives in place of rivets is probably not a good idea, even though that is done that way as primary structure on some production airplanes - Grumman Americans, and Cessna jets come to mind. Our RV?s were not designed that way. If you are trying to fix an area of unsupported skin, then maybe it would be OK. But remember, this is a stressed skin structure where the skin carries part of the load. Your repair needs to be at least as strong as the original undamaged skin. Patching an area like this is usually done with a riveted doubler, as you mentioned, returning that part of the structure to it?s original, or better, strength. I understand your desire to end up with a polished airplane, and not wanting to see a patch. I think you should phone home (Vans) and get their take on it.
 
I have never had any luck getting structural adhesive to bond with aluminum. I would never trust it.
 
Just call Van?s and order a new skin. In the long run it is cheap, and you will not be looking at that area every time you get in the plane.

Carl
 
Not structure associated

Scott Hersha said:
So the dented area you are trying to fix is skin damage between any underlying structure? If you are considering repairing damage that involves skin attachment to a rib, or any other structural member, I would say that adhesives in place of rivets is probably not a good idea, even though that is done that way as primary structure on some production airplanes - Grumman Americans, and Cessna jets come to mind. Our RV?s were not designed that way. If you are trying to fix an area of unsupported skin, then maybe it would be OK. But remember, this is a stressed skin structure where the skin carries part of the load. Your repair needs to be at least as strong as the original undamaged skin. Patching an area like this is usually done with a riveted doubler, as you mentioned, returning that part of the structure to it?s original, or better, strength. I understand your desire to end up with a polished airplane, and not wanting to see a patch. I think you should phone home (Vans) and get their take on it.
Click to expand...

There is no structure associated. It's just the skin that I want to reenforce but it is adjacent to the rib aft of the static hole on the fuse skin of an RV-9A. The rib was not affected. So to answer another question, no, ordering a new skin is not an option as the entire aft bottom skin would have to come off.

Hope that clarifies. And thanks for the responses thus far.
 
Repair

1bigdog said:
There is no structure associated. It's just the skin that I want to reenforce but it is adjacent to the rib aft of the static hole on the fuse skin of an RV-9A. The rib was not affected. So to answer another question, no, ordering a new skin is not an option as the entire aft bottom skin would have to come off.

Hope that clarifies. And thanks for the responses thus far.
Click to expand...

A photo or two would help. If there is no underlying structure, there may not be a need to do anything. A dent in a skin can be filled. A bigger problem might be fixed with a doubler. Post a photo plz.
 
No photo op

wirejock said:
A photo or two would help. If there is no underlying structure, there may not be a need to do anything. A dent in a skin can be filled. A bigger problem might be fixed with a doubler. Post a photo plz.
Click to expand...

Hi Larry

Sorry about this but I'm not on any social media and don't have access to any photo hosting sites so it appears I cannot post images.

But at least I'm getting an idea where the (now to be considered essential) Canadian flag decal will be going.

Cheers.
 
Photo

1bigdog said:
Hi Larry

Sorry about this but I'm not on any social media and don't have access to any photo hosting sites so it appears I cannot post images.

But at least I'm getting an idea where the (now to be considered essential) Canadian flag decal will be going.

Cheers.
Click to expand...

Feel free to e-mail a photo. I will load to Imgur and post for you. E-mail is in my signature below
 
the photo's

Hi Larry

Very kind of you to offer. I've sent an image of the front and the back side.
The dent doctor was here earlier today to assess what he could do to flatten it out. He has to come back to do a bit more.
The holes are for the avery static port. The gun and bar bounced and the 2 horizontal indents just bellow the lowest rivet hole are where it bounced off the bottom of the avery static port disk.
Once flattened and re-enforced I'm considering cover below the static port with the ID plate. That or a decal because you can't really fill in when it's polished.

Cheers.
 
Dent photos

1bigdog said:
Hi Larry

Very kind of you to offer. I've sent an image of the front and the back side.
The dent doctor was here earlier today to assess what he could do to flatten it out. He has to come back to do a bit more.
The holes are for the avery static port. The gun and bar bounced and the 2 horizontal indents just bellow the lowest rivet hole are where it bounced off the bottom of the avery static port disk.
Once flattened and re-enforced I'm considering cover below the static port with the ID plate. That or a decal because you can't really fill in when it's polished.

Cheers.
Click to expand...

Here we go.
Photos
6kUYy6Fl.jpg

oDgQUtzl.jpg
 
Michael,
To me it looks like your entire problem has to do with the fact that you want a polished airplane (a worthy endeavor). If you were painting, it would be an easy fix with some body work. I honestly don’t know how you solve this problem because the metal has been stretched. Doing some sort of patch that you can cover with an appropriate decal depending on your overall scheme may be your best bet. To me, it doesn’t look structural from your photo - just cosmetic, and that is the problem. You could put a riveted patch there with a bullet hole decal right in the middle of it, like a B-17 coming back to base after a mission.... Or how about filling it to make it smooth, and then just install a covering decal that simply states “STATIC”.
I wish you the best of luck coming up with a fix and I’m anxious to see what you decide.
 
Last edited:
Thanks

So first, thanks for the public and direct feedback. I had sent a message VANS with images last week, so waiting on that response, but all your feed back is encouraging. I might err on the side of using the data plate so I can keep everything polished. Just waiting for that to come back from laser etching.

I'll be happy to post the final result. Just want VANS blessing on the approach. And hopefully the dent doctor can flatten this out sufficiently. That or I can to learn how to play the oil can.

Cheers
 
One thing that often works surprisingly well is to get a good auto-body bump-out specialist to try to fix it.

I've had to do that twice on airplanes, and both times, when he was done, I couldn't tell where the damage had been. In your case, there might be a small mark remaining that''ll be easy to cover with your data plate.

I'd expect that something like this will cost less than $100, even getting the expert to come to your shop, and it's worth a substantial tip, too.

Dave
 
1bigdog said:
So to answer another question, no, ordering a new skin is not an option as the entire aft bottom skin would have to come off.
Click to expand...

I second the auto-body guy option but if that does not work, then replace the skin. Removing an entire skin is not an option? Of course it is. I had to replace both horizontal stabilizer skins on my -10 thanks to a gust of wind. And I am now replacing both the right and left fuselage skins and bottom skin aft of the main wing spar due to an aircraft lift failure that caused a wrinkle aft of the spar - even if the wrinkle had been fixable, I had to pull the skins to check for structural damage. Oh, yes, and I also removed the upper deck skin on my -6A to facilitate the panel change. You may not like the option (I certainly didn't) but it is still an option. Do what you have to do to make your aircraft right.
 
Talk to Vans about the possibility of putting one of their access panels back there. You could label it "ELT access" or other purposeful label to deflect attention from it.
Or refer to AC43 for process to rivet in a structural patch.
 
Last edited:
Good backup plan

Ralph Inkster said:
Talk to Vans about the possibility of putting one of their access panels back there. You could label it "ELT access" or other purposeful label to deflect attention from it.
Or refer to AC43 for process to rivet in a structural patch.
Click to expand...

That is a really creative backup plan. VANS did respond today. They are fine with the approach to use a small doubler after flattened and then the ID plate on top. The dent guy was here yesterday and will be back next week to shrink the problem. If for some reason he cannot do an adequate job I'll talk to vans about what flat panel options they have that could be used in that location.

Thanks
 
Doubler

1bigdog said:
That is a really creative backup plan. VANS did respond today. They are fine with the approach to use a small doubler after flattened and then the ID plate on top. The dent guy was here yesterday and will be back next week to shrink the problem. If for some reason he cannot do an adequate job I'll talk to vans about what flat panel options they have that could be used in that location.

Thanks
Click to expand...

Simple. Cut a doubler the same size as the data plate. Doubler inside. Use four of the rivets all the way through to hold the data plate. All the other rivets holding the doubler will be hidden behind the data plate.
 
CQ Dimpler to the rescue

So, the inherent problem is shrinking the skin to lay flat enough such that the backing doubler remains flat and the ID plate goes on top of a flat surface as well.

Using the QC dimpler I can pull the skin back in. Just need to strategically place dimples in and around the footprint of the dent and that will pull everything flat, most likely more easily than the dent guy can do (although I do need to thank him for the time spent).

I will send a followup about this to all. I'm supposed to get the ID plate back today so I can then see how everything fits and then get back on track.

All I can say is ... Oy.
 
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