Visit our Popular Forums

DryFly · 10-21-2012, 05:47 PM

After searching through this great forum (a truly incredible amount of information resides here) I've decided that I'm going to drop the belly pan on my 72 Argosy 20' and remove the insulation. My question is, why replace the belly pan? What purpose does it fulfill besides keeping the insulation in place - all damp and providing an opportunity for rot and rust by retaining moisture? If I left it off it would be easy to paint the bottom of the plywood floor and the frame members and keep them maintained.
What am I missing? I know there must be something.

Belegedhel · 10-21-2012, 06:44 PM

Hi,

I believe that the original idea about having a bellypan was to make the entire outer surface of the trailer as aerodynamic as possible. Certainly, there are plenty of SOBs out there that have no bellypan, but then they have the general aerodynamics of a barn... At the same time, most Airstream trailers have various items that break up the aerodynamics of the trailer, so maybe having an exposed frame doesn't make much difference. So, I would offer the following:

The belly pan does protect your Insulation from being stripped off by the wind, etc.. You will want insulation, but i wouldn't recommend more of the pink furry stuff. It also protects your valves, plumbing, tanks, etc.. And finally, it adds to the aesthetic, since the pan forms the "wraps that go along the sides of the trailer (plus, your banana wraps aren't going to stay put without being attached to the belly skin).

I put all new aluminum in my bellypan, and it looks better than the upper shell. I feel like peeking underneath every so often for inspiration.

Good luck!

Alumaholic · 10-21-2012, 07:51 PM

In addition to what Belegedhel has stated, Airstreams are enclosed to protect pipes and holding tanks from freezing when we use them in cold weather.

dibAL · 10-21-2012, 08:03 PM

You certainly don't need the insulation, especially if you're not camping in extreme conditions. The belly pan protects the frame and, more importantly, the plywood floor which does not benefit from exposure to moisture. If you don't intend to move I suppose you could leave the belly pan off. Almost every time we've towed we've run into rain, no matter what the forecast.

Shacksman · 10-21-2012, 08:11 PM

Quote:

Originally Posted by DryFly

After searching through this great forum (a truly incredible amount of information resides here) I've decided that I'm going to drop the belly pan on my 72 Argosy 20' and remove the insulation. My question is, why replace the belly pan? What purpose does it fulfill besides keeping the insulation in place - all damp and providing an opportunity for rot and rust by retaining moisture? If I left it off it would be easy to paint the bottom of the plywood floor and the frame members and keep them maintained.
What am I missing? I know there must be something.

Where are the mice, rats and snakes going to live if you remove their home?

The 2002 CCD model came from the factory without bellypan or insulation!!

TankerIP · 10-21-2012, 08:41 PM

My 2002 International A/S has no pan. I think there were 2 or three years' of this and the CCD model that did not have them. It is clear for those of us who have these that we have a "three season" trailer. Not really a problem for those of us who live in Texas and don't travel too far north in the Winter.

At least, I can easily inspect the undercarriage. I have access to plumbing, pipes, wires, etc.

Belegedhel · 10-22-2012, 07:13 AM

I have doubts that having a belly pan simply covering pipes and tanks provides much insulation in extremely cold situations. That being said, it seems like in the original layout of my trailer, the furnace fed hot air into the cavity between the sub floor and the bellypan, I assume to keep the fresh water tank warm. I would argue in favor of having some insulation down there, though, even if you live in a warm environment--you need to insulate the interior of the trailer from the heat that is radiating up off of the highway. I used closed cell foam with a layer of reflectex.

When I replaced my belly pan, I struck something of a compromise in my design. I broke up the continuous center section into three removeable panels that support fresh and grey tanks, and two riveted panels that cover the remainder. So if I need to look at the plumbing and dump valve, I only need to drill out the rivets on a "24 x 52" panel.

One thing that is no doubt, and that is that the interface between aluminum belly pan and steel frame resulted in a lot of corrosion to both on my trailer. Hopefully my rebuild will have less of that with all the POR-15 and top coat that I slopped on the frame.

good luck!

perryg114 · 10-22-2012, 07:21 AM

You can make an open design but you need to seal the wood with something and paint the frame. Although, if the truth were known, Airstreams would probably last longer if there were no belly pans because they could dry out and water can just drip out. The combination of different metals, leaks, and wet fiberglass insulation is the death of many Airstreams. The fact that these belly pans are riveted on makes maintenance and inspection a major pain. I ran without the last 6 ft of so of belly pan for about a year with no ill effects. I have belly pans now but the new sections are removable and there is no fiberglass under there and the frame has been painted with POR15.

Perry

runningbear5 · 10-22-2012, 07:32 AM

I did not even think about being able to remove belly pan
So glad I found this thread.
My tank for bathroom totally rotted trying to remove rotten parts of wood floor
Want to remove and replace insulation
I'm in Ohio this is a nice week of weather so I may get busy!

perryg114 · 10-22-2012, 07:38 AM

In case you have not figured it out yet. There are pans that hold up the holding tanks and the pan is the support for the tank.

Perry

runningbear5 · 10-23-2012, 05:43 PM

Yeah I had to dig in to get to rotting floor and discovered rusted away frame for tank

tphan · 10-23-2012, 07:19 PM

DryFly- I will give you my observations, after having gotten rid of my belly pan on a '72 about 6 years ago.
1) I no longer have any vermin living in my trailer.
2) I no longer have wet fiberglass insulation rotting my frame members.
3) I have immediate access to any and all issues occurring in that space.
4) I still have the "somewhat insulated" original black tank and freshwater tank pans, as they reside above the former belly pan.
5) I was still able to have the banana wraps, having added cross-pieces underneath to rivet them to. My trailer looks just like a belly-panned AS, unless you lay down on your back and look up underneath.
6) When I tow in the rain, the water from the trailer tires sprays up into the wheel wells, just like you would think. I have never seen water "jumping" up from the road to soak the bottom of my floor. If it did manage this feat, it would hit the Reflectix insulation attached to the bottom of the floor, and cause no harm.
As already stated in this thread, there are LOTS of RVs, trailers, cars, trucks, buses, etc. with no belly pan, even the '02 AS's. I think the aerodynamic pluses are minimal, at best.
Have fun with your trailer!

freeofecho · 10-24-2012, 03:29 AM

Oh boy I am so happy to have found this thread! When I bought my 58 Airstream on the road back the belly pan decided it didnt want to make the trip. It started ripping from the front all the way to the back. The people passing us were waving frantically at us and pointing at the trailer. Just turned out to be a hotel for mice and other vermin. We bought it in the desert and my poor boyfriend was covered in cactus needles from head to toe by the time he got the rest of it off!

DryFly · 10-24-2012, 06:59 PM

Tphan

"5) I was still able to have the banana wraps, having added cross-pieces underneath to rivet them to. My trailer looks just like a belly-panned AS, unless you lay down on your back and look up underneath."

I'm not quite clear on what this looks like, could you post a picture?

Also, I'm dropping the pan this weekend and I think I'll just leave it off, clean everything up, POR 15 on the cross members and call it good for a year or so. The pan material is pretty bad, so if I decide I feel or find a need to replace the pan, I'll deal with that down the road.

The photos would be helpful.

Thanks for all your input.

tphan · 10-28-2012, 07:33 PM

I don't have a photo handy, but I'll try to explain what I did and then take a pic if I still have to...
As I remember without going out to look in the dark, the Banana wraps attach underneath to the bottoms of the outriggers, with a pop-rivet. To give them more rigidity inbetween the outriggers, I used some of the scrap/leftover aluminum channel that I ended up with after gutting the interior. I cut this scrap to fit between the outriggers and attached it to the outriggers at the exact place that the bottom end of the banana wrap would hit it. I then put a couple pop-rivets through this sandwich. Seems to work just fine, and looks good too.

DryFly · 10-29-2012, 08:27 AM

tphan, thank you, that clarifies it.

DryFly · 11-10-2012, 05:50 PM

Well, I did it. This weekend my wife was out of town and I needed something to do. It's a balmy 42 degrees and no rain, so I decided what the heck, drop the belly pan. Probably 3/4 of the rivets had failed due to galvanic corrosion. So I crawled under the Argosy and started drilling on rivets. The pan came out fairly easily. In my case, it is a one piece affair as you can see in the second photo.
I'm very glad I did this, as the insulation had absorbed a lot of water. The first photo shows the lovely pink muck I found. The good news is there is almost no rot in the plywood floor, and while the bottom of the frame has rust almost everywhere, it all appears structurally sound. Had I not dropped the pan I bet I would have started to have serious issues in a year or so.
Luckily, the PO had stored the Argosy under cover for years. I'm not so lucky as to have covered storage, but I did a lot of protective caulking just after I got the trailer, so I think I've got most of the leaks. Living in the PNW though, I know this will be an ongoing battle.
I'm trying to dry everything out now and getting ready to clean the frame and paint it. I'll then paint the plywood and determine whether or not to bother insulating it.
At this point, I'm pretty sure I'm not going to replace the belly pan. Based on what I see has happened over the years, I agree with perryg that these trailers would probably benefit from not having a belly pan.
I'll post more with photos as I progress, slowly.

KYAirstream · 11-13-2012, 06:45 AM

Do you plan to insulate the floor somehow with rigid foam? And what about heat for the tanks?

DryFly · 11-14-2012, 08:21 AM

Quote:

Originally Posted by KYAirstream

Do you plan to insulate the floor somehow with rigid foam? And what about heat for the tanks?

I don't know yet about insulation - I want to check out Reflectix that others have used. I'll paint the underside of the plywood and clean up and paint the frame members. I've winterized the trailer and keep heat in the trailer so I'm not worried about freezing. All my tanks are contained above the floor.

DryFly · 03-02-2013, 06:52 PM

Well it's about time I update this thread.
I've sanded the frame and applied a rust converter, then painted the frame members. I've decided after a lot of angst to replace the belly pan. My initial thought was to use FRP panels - the thicker ones that are used on commercial box trailers. Fortunately before I spent the $, I called a manufacturer and talked with a very helpful tech, who told me that he thought FRP was too soft and would deteriorate rapidly due to rocks being thrown up against the belly of the trailer.
I was reluctant to replace the badly deteriorated aluminum pan with another aluminum pan, but after researching this forum and following the advice and wisdom of some 4 rivet members, chose to order some .032" 6061-T6 Aluminum. I'll add Reflectix before I install the new pan material.
More photos to follow.
One last thing, and I can't emphasize this enough, this is a great forum and plumbing the depths of knowledge freely given here is both enlightening and enjoyable. When we first purchased our Argosy, I quickly found it would be a LOT more work than I anticipated, and just as quickly became a little discouraged. After seeing what so many of the other members of this forum have taken on, and the encouragement and advice that so many of you offer, I am in a perverse way enjoying the challenge. I'll be donating to the forum fund next week, and would urge everyone else who has benefited as much as I have to do the same.