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Belegedhel · 11-08-2011, 07:34 AM

HI all,

I've been working on my '73 Globetrotter and encountered the expected, yet dreaded, rear end separation. The extent of the issue was not readily obvious until I pulled off the trim that covers the rivets that hold the banana wrap in place. That is when I saw the serious corrosion surrounding most of the rivets that connect the rear panel to the vertical steel frame plate (see pics). I am in the process of a shell off floor replacement (as there are lots of rotted spots in the floor), so all of the interior skins have been removed.

The question is, should I just replace the entire rear panel while I have the opportunity, or would anyone recommend a less dramatic means of repair (adding rivets in between the corroded spots, etc)?

In the event of a replacement, I have heard that the front and rear panels are thicker than the rest of the skin (because of their attachment to the steel uprights), but can't find a specific number--anyone know?

Inland RV Center, In · 11-08-2011, 08:15 AM

Quote:

Originally Posted by Belegedhel

HI all,

I've been working on my '73 Globetrotter and encountered the expected, yet dreaded, rear end separation. The extent of the issue was not readily obvious until I pulled off the trim that covers the rivets that hold the banana wrap in place. That is when I saw the serious corrosion surrounding most of the rivets that connect the rear panel to the vertical steel frame plate (see pics). I am in the process of a shell off floor replacement (as there are lots of rotted spots in the floor), so all of the interior skins have been removed.

The question is, should I just replace the entire rear panel while I have the opportunity, or would anyone recommend a less dramatic means of repair (adding rivets in between the corroded spots, etc)?

In the event of a replacement, I have heard that the front and rear panels are thicker than the rest of the skin (because of their attachment to the steel uprights), but can't find a specific number--anyone know?

You can use .040 or .050 aluminum.

Andy

perryg114 · 11-08-2011, 08:33 AM

I would replace the flat back panel and the L-Shaped piece of steel that was at the bottom of that plate that ties the floor to the frame and body. Your L-Shaped piece of steel is probably gone. I would use bucked rivets for all of this not pop or olympic rivets.

Perry

Splitrock · 11-08-2011, 08:59 AM

I'd do it the absolute best I can while I can. I like to find the leaks that caused the issue and fix them too.

Belegedhel · 11-08-2011, 03:28 PM

Thanks all. I also note that the lower streetside curved panel and the curbside front wing-window have been replaced at some point and were Olympic riveted in place. Should I drill out, and replace these with bucked rivets, or am I becoming too anal?

Lance M · 11-08-2011, 04:09 PM

Belegedhel,
Hello from Central Texas! You are not being too anal at all. Since you have access, now is the time to replace the olympic rivets with solid rivets. As far as the corroded flat panel goes, you have many options. You could replace the whole panel. You can underlay a patch of .025 6061 T6. The original exterior sheet needs to have the corrosion removed, treated and primed with epoxy polyamide or zinc chromate primer. You could also cut the panel off just below the lowest horizontal rib and reskin the part that you cut out with .040 2024 T-3 Alclad. You will have a seam there that won't be ugly, just out of place. Here is a link to how I repaired the same area on my '72 Ambassador. There are many ways to fix this. It all depends on how much time, skill, patience and money you have

Belegedhel · 08-21-2012, 08:26 AM

So after pondering this for several months while I wrestle with other issues, I am ready to proceed. Purchasing a piece of 36" x 48" 2024 T3 Alclad (to replace the entire section) seems freakishly expensive (shipping is significant, and it doesn't seem to be available locally). If I pulled the entire back panel off, and replaced, I might get the cleanest looking repair, but there is a good propability I might also screw some stuff up in the process. So I am leaning heavily toward cutting the back panel about ~10" from the bottom, and patching in a strip of 2024 AlClad down there. I don't think the extra row of rivets will look that out of place.

In order to get the full benefits of this plan, I would like to cut the panel with it in place (to avoid all the removing of rivets, just to replace them). The first question is: Am I nuts to try and make a clean cut with the panel in place? Second question: What is the right tool/technique for the job? I have electric shears, oscillating tools, and various types of saws, but it is hard to imagine getting a nice clean edge out of most of them.

perryg114 · 08-21-2012, 08:50 AM

Can you get to the back side of the panel or are you trying to do all this from the outside? Have you tried aircraft spruce? You might consider 6061-T6 aluminum. It is easier to get than 2024-T3.

2024T3 ALCLAD ALUMINUM from Aircraft Spruce

Perry

Belegedhel · 08-21-2012, 10:55 AM

The interior is completely stripped, as I just did a shell-off. I've got some .032 6061 T6 that I could patch in from inside, and just avoid cutting the existing piece at all. I think once the trim is back in place the rotted rivet holes on the current panel are invisible.

perryg114 · 08-21-2012, 11:27 AM

Yes that is what I was thinking. What does the hold down plate look like? Mine was rusted bad but intact when I did the rear of my trailer. I coated it with POR15. By the way POR15 bonds to corroded aluminum just as well. There is some other stuff out there that maybe just as good called Aluthane. As long as the corrosion is encapsulted I would not worry about leaving it.

MCU Aluthane (tm) - Moisture Cured Urethane Metallic Aluminum Paint

Perry

Aerowood · 08-21-2012, 04:44 PM

Quote:

Originally Posted by Belegedhel

So after pondering this for several months while I wrestle with other issues, I am ready to proceed. Purchasing a piece of 36" x 48" 2024 T3 Alclad (to replace the entire section) seems freakishly expensive (shipping is significant, and it doesn't seem to be available locally). If I pulled the entire back panel off, and replaced, I might get the cleanest looking repair, but there is a good propability I might also screw some stuff up in the process. So I am leaning heavily toward cutting the back panel about ~10" from the bottom, and patching in a strip of 2024 AlClad down there. I don't think the extra row of rivets will look that out of place.

In order to get the full benefits of this plan, I would like to cut the panel with it in place (to avoid all the removing of rivets, just to replace them). The first question is: Am I nuts to try and make a clean cut with the panel in place? Second question: What is the right tool/technique for the job? I have electric shears, oscillating tools, and various types of saws, but it is hard to imagine getting a nice clean edge out of most of them.

Splicing in a new section of the panel is OK if your mind is set on it, remember that you will have to cut the skin where it slides in between the corner skins and the interior vertical frame. The back skin is a really small skin section and I think it would be more work to splice then to replace after you look at all the additional rivets you will have to put into the splice. Just my opinion.

Aerowood · 08-21-2012, 04:47 PM

Quote:

Originally Posted by Belegedhel

The interior is completely stripped, as I just did a shell-off. I've got some .032 6061 T6 that I could patch in from inside, and just avoid cutting the existing piece at all. I think once the trim is back in place the rotted rivet holes on the current panel are invisible.

If you don't get rid of the corrosion it will not stop, and possibly start corroding the repair, what does the galvanized steel hold down plate look like? If its still there and rusting away it will also corrode out your repair

perryg114 · 08-21-2012, 06:48 PM

If you have a buck rivet gun then replace all of it. Fabricating a new hold down plate is probably going to be most of the work. Aerowood is right. You are this far into it why not do it right. If you don't want to take it on see if you can find an airplane sheet metal man that will moonlight. There are other members in your area that might help.

Perry

Belegedhel · 08-23-2012, 01:16 PM

Well, I didn't really have my heart set on doing a splice, and my natural instinct is always to do things the hard way (read go "all-out"). My motivation on this particular project was that my back panel extends all the way from the bumper to the bottom of the rear window, so it doesn't seem like that small of a job to me (not with all the other parts of the project waiting to be done). The other discouraging aspects of the job are that I would need to order a 4' x 4' sheet of 2024 T3, and just the shipping for something that size is over $77. Its probably too late to start worrying about costs, it just makes me grind my teeth to pay as much to ship something as it is worth. Can't find the stuff locally.

If I replace the whole panel, I would also have to remove the "AIRSTREAM" letters, and fighting my way through the fossilized gunk on the inside of the skin could take days. I know I could just shear off all the little studs and pop rivet the letters back on, but again, that doesn't feel like the "right" way to execute.

Belegedhel · 08-23-2012, 01:34 PM

I was just browsing around in the exterior repair section of the forums, and found a pdf document that purported to be the history of aluminum at Airstream, and it indicated that my '73 likely has skins made of 6061 T6 (contrary to the rumors I had heard regarding 70's era trailers still using 2024 T3 Alclad). Anyone with a calibrated eyeball able to confirm?

Splitrock · 08-23-2012, 02:12 PM

Quote:

Originally Posted by Belegedhel

I was just browsing around in the exterior repair section of the forums, and found a pdf document that purported to be the history of aluminum at Airstream, and it indicated that my '73 likely has skins made of 6061 T6 (contrary to the rumors I had heard regarding 70's era trailers still using 2024 T3 Alclad). Anyone with a calibrated eyeball able to confirm?

I had been wondering if this type of question could be objectively answered by Airstream Corporation. I had a question about my 1976 and the first person I talked to, after the pickup, answered my question. I was pretty impressed.

Aerowood · 08-23-2012, 03:59 PM

My 71 GT straight panels were 2024-T3 and I believe the compound curve panels are 6061-T6. I could be wrong on the 6061 but I know for sure that the compound panels are not 2024-T3

perryg114 · 08-24-2012, 07:37 AM

What do the panels have marked on them?

Belegedhel · 08-25-2012, 01:25 PM

No markings anywhere.

Belegedhel · 08-28-2012, 02:21 PM

Well, I took Splitrock's advice and called the mothership and left them a voice mail regarding my skin conundrum. Got a call back a few hours later, and was told that starting in 1972, the skin material changed to the 6061 T6, .032" thickness all around. This is for the flat and formed sections as well. So there you go. I suppose that My only dilemma now is that my flat sections have the milled appearance, and it doesn't seem that you can buy milled 6061 sheet.