Filiform, how much is too much?

[daved20319]

In the process of a shell off resto, got it gutted down to the ribs last week. Considering the number of leaks we had, the inside of the ext. skins looks surprisingly good, EXCEPT for the very top full length seam down both sides of the trailer. There's corrosion the full length, and while most of it is surface, there's a fair number of areas where the aluminum is flaking. I'm afraid that by the time I've scraped and sanded down to clean metal, it's going to end up not much thicker than tin foil . Although replacing the panels is the right answer, it's out of the question, just too much required to make it happen. So here's my question.

In those areas where the corrosion is especially bad, is there some way to reinforce the skin from the inside after getting it cleaned up? I'm thinking Bondo or fiberglass, but I could also see bonding/riveting a panel to the inside. I'm wide open to other ideas or suggestions. Sorry I don't have any pics yet, I've taken a ton, but haven't downloaded them to my computer yet. Soon, I hope. Thanks!

Dave

[scamp]

If the corrossion is that bad then panel replacement is recommended ,bondo will not provide strength, it's hard to give you a opinion without pictures or seeing it .

Don

[xrvr]

Is that filiform? Jim

[truckasaurus]

You can remove all trace of corrosion and add a doubler strip but it would be as much work as a full panel replacement. Total removal of corrosion is time consuming and dirty. You can use an acid etch etc but it's half a job. A pic would help if possible

[daved20319]

Originally Posted by truckasaurus

You can remove all trace of corrosion and add a doubler strip but it would be as much work as a full panel replacement. Total removal of corrosion is time consuming and dirty. You can use an acid etch etc but it's half a job. A pic would help if possible

Time I've got, and dirty I'm not scared off. As to it being as much work as full panel replacement, I don't think so. To truly fix this, I'd have to remove the top center panel, as well as the two panels on either side. That would mean removing the A/C (which I'm going to do anyway), the awnings, the air and plumbing vents, as well as most of the windows and the door. I'm just not able to invest that much time and effort.

Jim, probably not filiform, just aluminum corrosion run rampant. I've seen this sort of thing before, with underground aluminum wiring back in my days as an electrician. All it takes is one little nick in the insulation, and the stuff will blow up to 3 or 4 times its original size.

I finally downloaded my camera, here's a pic of what I'm dealing with. Note, this is probably the worst spot, but there are several others almost as bad, plus a few more I'm not as concerned about.



The thing that still seems odd to me is that this is all on the very highest seam on the entire trailer. I wouldn't have been surprised if it had been where the awnings were riveted, but these seams are a good deal higher, go figure. Again, any ideas or suggestions (that DON'T include panel replacement ) are much appreciated. Later.

Dave

[ROBERT CROSS]

It may very well have started as filiform at the seam..but I think your way beyond that now, thats plain old flaky corrosion in the pic.
If possible remove the corrosion & patch....if not replace the infected panels.

Is that panel a repair?...that seam & those rivets look a bit odd, no sealant.

Bob

[Foiled Again]

Look at the rivet line. Unless the picture posted upside down, the bottom panel is the outside one! And the rivets do not look like either original OR Olympic rivets. I would start to wonder - what the heck is UNDER that panel. Dissimilar metals maybe? The actual brown rust says Iron or Steel to me - filiform is white. Like maybe some kind of previous owner "fix" to add steel shelves, etc? Or could there have been damage that actually sliced through the panel, and someone tried to back it with whatever they had handy like the kind of metal that got used in old furnace pipes or a coffee can?

The worst part pretty clearly goes all the way through the panel - look slightly above those flat top rivets. I wonder if some of that corrosion didn't start on the BACK side of the panel.

Filiform doesn't stop by itself, and in 50 years, left outside and in a damp climate it could get this bad. If an Airstream is in a climate controlled garage it'll slow almost to a stop... but outside in the elements? Well in another 50 years, probably everything but the axles and tires will be gone.

paula

[truckasaurus]

Hey Dave, to repair the damaged areas you can add a repair patch inside the trailer cut out the damage and rivet a new insert repair section; all fabricated to account for the seam between two panels. This would be a flush patch repair with a joggled landed doubler. It is time consuming to complete and requires more skill than average and if you have a few areas to address the time will add up but it would not require you to move vents etc.

[daved20319]

Originally Posted by Foiled Again

Look at the rivet line. Unless the picture posted upside down, the bottom panel is the outside one! And the rivets do not look like either original OR Olympic rivets. I would start to wonder - what the heck is UNDER that panel. Dissimilar metals maybe? The actual brown rust says Iron or Steel to me - filiform is white. Like maybe some kind of previous owner "fix" to add steel shelves, etc? Or could there have been damage that actually sliced through the panel, and someone tried to back it with whatever they had handy like the kind of metal that got used in old furnace pipes or a coffee can?

The worst part pretty clearly goes all the way through the panel - look slightly above those flat top rivets. I wonder if some of that corrosion didn't start on the BACK side of the panel.

Filiform doesn't stop by itself, and in 50 years, left outside and in a damp climate it could get this bad. If an Airstream is in a climate controlled garage it'll slow almost to a stop... but outside in the elements? Well in another 50 years, probably everything but the axles and tires will be gone.

paula

Optical illusion, Paula, the lower panel IS under the upper one . And it's definitely aluminum over aluminum, with standard buck rivets. I don't know what's up with the weird color, I suspect it's organic, i.e. mold, not rust. Couldn't say whether the seam and rivets look odd, but both are consistent with the rest of the trailer.

I did a fairly detailed inspection of the rivets and ribs today, I've read plenty of posts about hit or miss craftsmanship putting these things together, but I'd say this one was assembled by the "A" team . Nice, consistent job bucking the rivets, I'm pretty comfortable calling anything that's sub-standard either normal wear and tear or poorly done repairs, and there are a couple of the latter, very obvious. Bear in mind, if we hadn't bought this when we did, it was on its way to the scrap yard. All in all, it's actually looking a lot better than I expected. Now if only that "better than expected" trend continues to the frame.... Later, and thanks for all the input.

Dave

[perryg114]

That does look ugly. Where has this trailer spent most of its life? I have not seen that sort of corrosion before. So unless it is very close to the ocean or some place with really bad acid rain, I don't know what happened to it. Wire brush it and coat with something like Aluthane. It is a moisture cured polyurethane that has aluminum particles in it. It might also be possible to coat it from the inside. You will have to seal it off with some sort of paint or coating or replace it. If it is left bare it will continue to corrode in the state it is in. POR15 on the inside would seal the pinholes up. What is the history of the trailer?

Perry

[vinstream]

I have seen that type of damage around wheel wells and frame connection areas. This is major corrosion that based on your pictures needs panel replacement. There is nothing I have found for quick fix material like Bondo that works because patch type material traps water and speeds up the damage. Once Aluminum looks like white corn flakes there is no way that I know of you turn the damage around and return it to some point that it will work.

[xrvr]

I had a 72 that had that same stuff on the belly pan and my 64 Avion,s belly pan had the same thing underneath. From the beach!? Jim

[Aerowood]

What you are seeing is called exfoliation. I have seen way to much of this in my aviation career. It is caused by the lack of sealing in the lap seams with moisture continuing to invade the seams and water acting like an electrolyte. If you are unable to replace the panels they will require patching. You will first need to level and support the trailer before opening up the seams to prevent the trailer from bowing with the amount of rivets you will need to remove. Open the entire seam where the corrosion is evident. Clean the areas that will clean up without repair. I like bead blasting as it removes all corrosion. Once the areas that will clean up are acceptable, prime the mating surfaces and shoot the seams back together wet with sealant, leaving the areas that need repair open and free of sealant. Repairs can be of two different types, flush or external, with flush being more visual appealing. Which ever method you choose, I would be willing to walk you through it with the different repair technicals. PM me if you want or need additional information

[dbj216]

Very kind of you Aerowood to offer to help Dave out on this. I gather he is going to resurrect this old Airstream from the ground up. Vinstream posted a 4 minute video showing an upper and lower side panel replacement. Even working half as fast as the guys in the video, it would only be 8 minutes!

Dave, there are suppliers that sell replacement end cap panels. It is a class A major project, but it can be done. Airstream employees do it 50 times a week. After reading Aerowood's rebuild thread, check out submarine's 47 Liner thread.


David

http://www.airforums.com/forums/f59/...on-113774.html

[daved20319]

Very kind indeed, and I will definitely be in touch, Aerowood. My focus right now is getting the shell off the frame, frame issues and leaks are the primary reason for starting the project. Once I have a flat, level frame with a good deck, I'll be ready to start in on the shell repairs.

David, I haven't seen the video you mentioned, but I'm NOT talking about replacing end caps, I'd be replacing the entire top half of the straight section of my AS. Add in the fact that I'm working by myself, and you should start to get an idea of the size of the job. So some sort of patch will have to be the answer.

Perry, I can't speak to this things history before we bought it, but based on things like bumper stickers and an old newspaper stuffed under the bath slider lower track, it's seen some miles, and been to the opposite corner of the country and back at least once. We bought it in Tacoma, WA, and it had been lived in full time by the PO, although we don't know how long. We DO know he/they were heavy smokers. We thought the interior walls were brown, a couple of gallons of Pro 409 later and the true off-white color was revealed .

It hasn't had an easy life since we got it, either, it spent the first 5 or 6 years parked on a mountain, left to fend for itself over the winter. Come to think of it, that could be the cause of this corrosion, we used to get a lot more snow back then, it probably spent most of the winter pretty much buried in snow. It's spent the last 3 years mostly in my shop, I've either been working on it, or planning to. Before that, although no longer spending winters buried in a snow bank, it was still outside, fluctuating from cold and snowy to hot and dry. Needless to say, after all the work I'm doing/planning on doing, unless we're on the road with it, it will live in my shop from now on .

Thanks again, Aerowood, and I WILL be in touch soon. Later.

Dave

[perryg114]

I like Aerowood's fix better.

Perry

[dbj216]

Very nice you have a shop for your Airstream and a warm, dry place to work on it. I was guessing it was an end cap panel judging by the curve in the rivet line. Straight sections are easier to work on.

Some of our Airstreams, like people, have had a pretty hard life. My 66 and 86 are both outdoor Minnesota trailers. It isn't the greatest climate in the country.

David

[perryg114]

Is that a lap joint overlap region? It looks like that area was out in the open. It does look like an area like an unsealed lap seem or where water has gotten under caulk and stayed there.

Perry

Originally Posted by Aerowood

What you are seeing is called exfoliation. I have seen way to much of this in my aviation career. It is caused by the lack of sealing in the lap seams with moisture continuing to invade the seams and water acting like an electrolyte. If you are unable to replace the panels they will require patching. You will first need to level and support the trailer before opening up the seams to prevent the trailer from bowing with the amount of rivets you will need to remove. Open the entire seam where the corrosion is evident. Clean the areas that will clean up without repair. I like bead blasting as it removes all corrosion. Once the areas that will clean up are acceptable, prime the mating surfaces and shoot the seams back together wet with sealant, leaving the areas that need repair open and free of sealant. Repairs can be of two different types, flush or external, with flush being more visual appealing. Which ever method you choose, I would be willing to walk you through it with the different repair technicals. PM me if you want or need additional information