Front End Separation? Advice sought for front end skin repair.

[Re-Pete]

Part 1

Is this what they term Front End Separation? I’m using a lot of pictures so I’m breaking this first post into two posts. I’m looking for answers, but I’m mainly looking for help and advice on repairing this damage. I’m posting pictures to make it more visual and I’ll tell you what my plan is, but for those that have experience in shell repair or similar I’d love to hear from you, because I at this point have no skin repair experience and honestly I'd rather learn from your mistakes.







The pics I've posted are of front end damage to my 1992 Excella. I discovered it when I began removing the bottom trim as I was preparing to do a shell off. Once the trim was off and I’d separated the shell it became evident that the damage was worse than it looked at first. The damage goes far beyond the stress fatigued and cracked area above the attachment rivet line to the floor channel on the curbside front. The rivet holes on both front corners are extremely wallowed out (worse on the street side). Many of the original 1/8” rivet holes on the street side are now close to 3/8” in diameter.



None of the existing holes on the curved section of either corner are reusable.
Ironically the front flat panel section between the front corners is pristine. The rivets are still in it because they were not even attached to the floor channel when we separated the shell. The reason for this is difficult to say. There were holes for them in the floor channel and gouges on the outside of the floor channel that appear to be the result from where the back of the rivets rubbed against it. So, the rivets either pulled through somehow intact or there’s a good chance they were never bucked properly to begin with. After inspecting the backside of the rivets I found they were not appear to be mushroomed as they should be. Certainly not to spec. as they are barely more than original diameter. I suspect poor installation on this part, but I’m just guessing.

[Re-Pete]

Part 2:
So, my plan is to cut off the bottom 3 or 4 inches of the corners and rivet in new aluminum. Then we’ll rivet in the replacement aluminum providing a new fastening edge for the corners. I’ll also replace the center panel. I’m installing LiFePo Batteries (lithium) and they do not require the exterior vented battery compartments.

Phyllis, my wife and I used some brown craft paper to trace the bottom edge of the corners so we can make patterns for the replacement aluminum. We have not trimmed the patterns to size so the repairs will not come up nearly so far on the corners, just a few inches is what I have in mind. I was just trying to get an idea of what the shape will look like, especially since we’ll be starting with straight pieces.





The game plan is to slide the new aluminum beneath the existing to it laps over from above. It sounds really good in theory, but it’s also going depend a great deal on how good a job we can do cutting out the bad sections. This repair will be above the bottom trim, so it will completely visible. For that reason I’d really like it to look good.

The aluminum is coming from AirParts.com. The exact aluminum alloy Alco 3005 – H18 isn’t available, but Chris at AirParts has been working with me. She graciously sent me 3 different alloy samples to polish so I could buy something I felt was a good match. The polishing was similar on all three, one did perform the best a 3003-H14, but I chose the 5052-H32 because it polished well and it’s very corrosion resistant and durable. The third one was the 2024-T3. Since I’m not putting a clear coat on it so this one did not seem like a good choice as it’s not real corrosion resistant. Chris told me it’s the aluminum Airstream currently uses. Bottom line, all three are probably fine, but I thought it was nice that AirParts showed me that kind of concern.



If anyone has any experience with this problem or similar I’d love to hear from you.

[Gene]

As a general rule, anything that has water running down it needs to have the upper piece lapped over the lower one with a few inch overlap. So if you are planning on installing a piece part way up the panel, the lower piece should go behind it and have sealer on it underneath. Assuming there are rock guards, they will hide the seam and sort of protect it, but water is inevitable. Finding the reason for the separation is important so it won't happen again. Other than that, I am useless. Good luck.

[57Vintage]

I'm not sure I will be of any help, but in reviewing your photos I was a little surprised there wasn't a steel reinforcement behind your center panel. On the older ones like ours a L shaped panel has a lower horizontal lip that sits inside the channel and bolt down through the front crossmember and has several rows of rivets up the front panel (about 18"). At least the rivet pattern I see on the outside doesn't appear to show there was one.

Was there any indication of separation between your subfloor/channel and the frame? I assume there is very little outrigger support on those curved portions. Hopefully someone more familiar with your years can point you to more specifics. Good luck.

[Re-Pete]

Originally Posted by Gene

As a general rule, anything that has water running down it needs to have the upper piece lapped over the lower one with a few inch overlap. So if you are planning on installing a piece part way up the panel, the lower piece should go behind it and have sealer on it underneath. Assuming there are rock guards, they will hide the seam and sort of protect it, but water is inevitable. Finding the reason for the separation is important so it won't happen again. Other than that, I am useless. Good luck.

Yes, my plan is to overlap like siding or shingles. I was just saying that I'm worried about my cutting ability. Also wondering what the best cutting tool for this job is since I'll be cutting on a complex curve? Mainly, I worry about the finished edge being smooth, straight and or even, not jagged. As for the separation, I agree, knowing why is important. I'm thinking the improper riveting of the center panel connecting the corner panels was a major contributor. That most likely destabilized the entire front connection.

[Re-Pete]

Originally Posted by 57Vintage

I'm not sure I will be of any help, but in reviewing your photos I was a little surprised there wasn't a steel reinforcement behind your center panel. On the older ones like ours a L shaped panel has a lower horizontal lip that sits inside the channel and bolt down through the front crossmember and has several rows of rivets up the front panel (about 18"). At least the rivet pattern I see on the outside doesn't appear to show there was one.

Was there any indication of separation between your subfloor/channel and the frame? I assume there is very little outrigger support on those curved portions. Hopefully someone more familiar with your years can point you to more specifics. Good luck.

Yes, I'm familiar with the front steel plate and rivet pattern on older models. My friend Jeff's Argosy was built like that. He even added it to the rear of his Argosy. I have not seen it on models in my time period, but it seems like something I might be able to add. Do you have any tips on tools, technique, etc. I should use when cutting on the shell and for cutting the new metal for patching?

[57Vintage]

The cutting part on new metal might be the easiest part. You can get non-ferrous blades to fit a skil saw and use some type of guide to get a straight line. I use these blades on a skil saw (7-3/4") for long straight cuts and on my compound miter saw (10") to cut aluminum tubing. Rub a little bar soap on the blade to keep it from gumming up with chips and cut fairly slowly.

https://www.homedepot.com/p/DIABLO-7...E&gclsrc=aw.ds

Cutting the existing shell will require more patience. I wouldn't cut any higher than needed to get good metal. It also minimizes any compound curve. If you have aviation snips that might be the sufficient, but will be slower. A cutting disc on a grinder will be quicker, but easier to make mistakes. Any ribs in the way should probably be loosened first to keep from damaging them.

If you have to drill out the rivets from the channel, I'd take my time there and try to remove without enlarging the holes in the channel. I realize that reusing those holes would be time consuming. You'd have to size the new patches. Drill the rivet holes along the splice, cleco them and then mark the patch from the inside of the channel for the lower rivets. It would get difficult, that patch has to be held against the channel tightly for the holes to be accurate. It may just easier to drill new holes on the channel attachment and move on. Your choice, just my thoughts of ways to accomplish.

I'd also use a thin layer of Trempro between the patch and shell before bucking the rivets and then reseal everything from the inside.

Keep us informed. Look forward to see the rest of the rebuild.

[Re-Pete]

Thanks Harold.
I probably should have made it clear that I have replaced the original channel. That was another rigmarole, because as I'm certain you know, it's never just easy! But in this case I'll be drilling all new holes, in the channel at least.

For the most part all of the other rivet holes in the shell are in good shape. I did take my time drilling out the rivets and so I shouldn't have much trouble there. I also purchased some of the slightly larger (5/32") shank buck rivets with the same size heads as the 1/8" from Vintage Trailer Supply for holes that have become slightly larger.

Good tip on the "skil" saw, I actually have been using a non-ferrous metal blade on my compound miter for cutting the new floor channel, etc. I've also gotten pretty handy with my 4-1/2" grinder using cut blades, while rebuilding my frame, but thinking about free handing these shell cuts makes me plenty nervous. Like you said, more or less, Slow and Steady.

My friend Jeff suggested using a router with a top bearing straight bit to make the cuts along a plywood form. I think he has some experience with this which why I'm hoping he'll be able to give me a hand.


Also, I'll make sure to loosen the affected ribs before cutting, and I appreciate that you reminded me.

[crispyboy]

I purchased a 1994 trailer with front end separation and repaired it back in 2013. I installed a hold down plate and three new front panels. Trailer has been rock solid since the repair.



https://www.airforums.com/forums/f38...avy-98728.html

[guskmg]

On your repair methods. The front and rear needs to be addressed so as to not go through this again. I have talked to Colin Hyde and he is the guru on reinforcing to eliminate "front end and rear end sag." He has much better techniques than Airstream or any of their dealers.
Colin Hyde
(518) 578-7772
colin@colinhydetrailerrestorations.com
Plattsburgh , NY
guskmg

[Gene]

My experience with cutting metal has always been depressing. First of all, the cutting tools are made for righties and are awkward in my left hand. Not your problem perhaps, but I don't know. I have a pretty good understanding of wood, but metal is different and cutting compound curves requires lots and lots of practice. It may be worth taking your aluminum to a metal shop and have them do it. At least if they screw it up it is on them. Otherwise order extra aluminum and practice, practice, practice.

Your friends suggestion of using a router may be a good one. A router takes some practice as well. Using a jig to make a cut is always a good idea. Keeping a steady hand without one is pretty hard to do. The time used in making a jig is made up for in accuracy and not ruining materials.

At least ten years ago there were threads about front or rear end separation. Over the years Airstream has tried to save a few bucks by cheapening the frame, subfloor or other parts that keep the trailers together. I am not surprised your friend's older Argosy had more bracing and I would think copying what his had may be good for your trailer. When people got Airstream to fix separation, I think Airstream installed something that looked like tabs on the outside—not pretty. My memory is vague, but there should be threads from back then to see what Airstream did. It may be helpful. Wish I could remember more, but can't and I understand looking for them might not be worth the time.

[knowmercy]

Hello, I did want to comment just to offer up advice as someone who's done a rear end separation repair. Whether or not it's successful, we'll know in another 40 years. Anyhow, You can get some electric shears from harbor freight which I highly recommend for this type of patch. They're only about $35 when I got mine and they'll produce a VERY clean result. Significantly better than from the factory in my experience. The second thing I wanted to offer as a consideration only. The aluminum in that area is fairly stressed from the tongue. You can probably watch the frame and shell move significantly when they're apart, but they still settle a little bit even when they're together. I'd recommend using the 6061T6 or 2024T3 in this area because it has slightly better strength properties than the 5053, which tends to be rather malleable. This is only a suggestion, but perhaps considering it might help you understand if 5053 is enough, or not. Anyhow, Looking forward to your result! Glad to see you've got everything taken apart and identified how you're planning to fix it. I do agree with you that those solid rivets are not bucked to general specs, yet alone "aircraft" standards. Cheers!

[oldfulltimer]

Like many others, I experience the same separation in my 1993 34 foot Excella. I posted to this site and Colin Hyde responded almost immediately about the problem. Seems that in the late 80's and early 90's, JC ended the use of a "hold-down" plate to save a few cents and with the flexing of the shell to frame, the rivets enlarge the holes and before long they hold nothing. Turns out I lived less than 100 miles from Colin Hyde and visited him and his shop men made me a hold-down plate and C-channel repair strips. Similarly, at that time, Vintage Trailer Supply was 30 miles away and I obtained their buck rivet kit that had everything you needed for the repairs. The only cutting of the shell that I did was to eliminate the battery boxes since I went with AGMs and didn't need the outside venting and access. While this was open, the steel hold-down (believe it was 1/8" steel) was welded to the frame. The area at the front bottom (worse than yours) was repaired by adding (buck riveting) pieces of aluminum to the inside of the shell and overlapping the outer "C" channel. Rivets were one and a half inches on center. Most of this riveting was hidden by the stone shields when all was reassembled. The aluminum piece that eliminated the battery boxes was securely riveted to the upright frame and about sixty rivets were used to attach that to the hold-down plate. A thin piece of plastic was used between the steel and aluminum to eliminate electrolysis.

Have put on a lot of miles since that was done in 2014 and it's rock solid.

Took lots of pictures to show to a future purchaser.

Dave

[Re-Pete]

Originally Posted by crispyboy

I purchased a 1994 trailer with front end separation and repaired it back in 2013. I installed a hold down plate and three new front panels. Trailer has been rock solid since the repair.
https://www.airforums.com/forums/f38...avy-98728.html

Crispyboy,
Excellent repair post on your 1994 front end. Unbelievably helpful. Really nice workmanship. While I'm planning to repair my quarter panels you did a fantastic job with the full replacement. I'm also going to be adding a junction box for my umbilical cord and I agree with your statement that it's what AS should be doing. Maybe they do now. I also greatly reinforced the area above my spare tire rack, which in my case was simply a huge open void.



I've already purchased a 4' x 12' sheet of aluminum from AirParts.com and it should be arriving on Saturday. I have several other patches to do on mine that I did not want to get into in this thread. I expect this repair will be the most difficult.

[Re-Pete]

Originally Posted by oldfulltimer

Like many others, I experience the same separation in my 1993 34 foot Excella. I posted to this site and Colin Hyde responded almost immediately about the problem. Seems that in the late 80's and early 90's, JC ended the use of a "hold-down" plate to save a few cents and with the flexing of the shell to frame, the rivets enlarge the holes and before long they hold nothing. Turns out I lived less than 100 miles from Colin Hyde and visited him and his shop men made me a hold-down plate and C-channel repair strips. Similarly, at that time, Vintage Trailer Supply was 30 miles away and I obtained their buck rivet kit that had everything you needed for the repairs. The only cutting of the shell that I did was to eliminate the battery boxes since I went with AGMs and didn't need the outside venting and access. While this was open, the steel hold-down (believe it was 1/8" steel) was welded to the frame. The area at the front bottom (worse than yours) was repaired by adding (buck riveting) pieces of aluminum to the inside of the shell and overlapping the outer "C" channel. Rivets were one and a half inches on center. Most of this riveting was hidden by the stone shields when all was reassembled. The aluminum piece that eliminated the battery boxes was securely riveted to the upright frame and about sixty rivets were used to attach that to the hold-down plate. A thin piece of plastic was used between the steel and aluminum to eliminate electrolysis.

Have put on a lot of miles since that was done in 2014 and it's rock solid.
Took lots of pictures to show to a future purchaser.

Dave

Dave,
I'd love to those pictures. Feel free to PM me and share a link if they're online or I can send you my email address. They'd probably be very helpful.

[DGJackson]

Originally Posted by Gene

... I have a pretty good understanding of wood, but metal is different and cutting compound curves requires lots and lots of practice.

I'm going to endorse and expand on difficulty in turning flat, square things into curved & arched things - That look straight. Before playing with airstreams I built wooden canoes and small wood boats. this required taking 1/4 to 3/8 thick wood and bending, twisting, and cutting in curves to produce what looked to be straight lines. The technique used in wooden boats is called spiling - several You Tube video on art & technique of the process.

I would suggest starting with roofing/valley tin. It's a little more costly that craft paper but it's rigid and cheaper than the final aluminum you will be using. I used it for spiling curves to replace a couple of 4" boards on a 30' wooden boat. We had to use 8" wide boards in some places to get 4" wide arched board. That's how I might approach the problem. Good Luck - I'll be following along.

[Re-Pete]

Originally Posted by Gene

My experience with cutting metal has always been depressing. First of all, the cutting tools are made for righties and are awkward in my left hand. Not your problem perhaps, but I don't know. I have a pretty good understanding of wood, but metal is different and cutting compound curves requires lots and lots of practice. It may be worth taking your aluminum to a metal shop and have them do it. At least if they screw it up it is on them. Otherwise order extra aluminum and practice, practice, practice.

Your friends suggestion of using a router may be a good one. A router takes some practice as well. Using a jig to make a cut is always a good idea. Keeping a steady hand without one is pretty hard to do. The time used in making a jig is made up for in accuracy and not ruining materials.

At least ten years ago there were threads about front or rear end separation. Over the years Airstream has tried to save a few bucks by cheapening the frame, subfloor or other parts that keep the trailers together. I am not surprised your friend's older Argosy had more bracing and I would think copying what his had may be good for your trailer. When people got Airstream to fix separation, I think Airstream installed something that looked like tabs on the outside—not pretty. My memory is vague, but there should be threads from back then to see what Airstream did. It may be helpful. Wish I could remember more, but can't and I understand looking for them might not be worth the time.

Gene,
Thanks for your information and suggestions. I can tell they come from experience. Having learned from experience, often the hard way, I'm taking it all to heart.

Pete

[Re-Pete]

Originally Posted by DGJackson

I'm going to endorse and expand on difficulty in turning flat, square things into curved & arched things - That look straight. Before playing with airstreams I built wooden canoes and small wood boats. this required taking 1/4 to 3/8 thick wood and bending, twisting, and cutting in curves to produce what looked to be straight lines. The technique used in wooden boats is called spiling - several You Tube video on art & technique of the process.

I would suggest starting with roofing/valley tin. It's a little more costly that craft paper but it's rigid and cheaper than the final aluminum you will be using. I used it for spiling curves to replace a couple of 4" boards on a 30' wooden boat. We had to use 8" wide boards in some places to get 4" wide arched board. That's how I might approach the problem. Good Luck - I'll be following along.

DG,
Thank you. Using valley metal for practice send like a good idea. I'd rather makes my missteps and mistakes on practice material.
Actually because it's thin it might work well to pattern from. Anyway, thanks for your input.

Pete

[crispyboy]

Glad my post was of some help for you. The quarter panels on my trailer were dented in from road debris hit by the previous owner and the center panel was cracked from fatigue.
One other thing I did before putting back together is to put thick aluminum plating (1/4") inside the skin so the the lower awning support fasteners would have something meaty to sink into and distribute the wind load.
Since your frame is so open this would be a good time to run some stainless steel brake lines "just in case" you ever decide to go the electric over hydraulic brakes in the future.

[ALUMINUMINUM]

Hello,


Your frame is beautiful, adding a front hold-down seems inevitable.

A hand-held variable speed electric shear in the style from Bosch, Milwaukee, Harbor Freight and some others, became an indispensable tool to my 68GT build. They are very safe, accurate, quiet, and comfortable to handle.

Not likely that you'll ever regret having one at hand.