Belly pan - factory rivits?

[rwnash]

I need to repair the belly pan after the blind ("POP" style) rivets failed and some of the contents of the trunk were lost. I am going to use a piece of thicker aluminum for the trunk floor and replace the failed rivets. However, I noticed that some of the rivets about 3 to 4 feet forward of the trunk are seriously corroded.

My trailer has two types of blind rivets; small ones with about 3/16 inch heads that have held up fairly well and large ones with 5/8 inch heads. The large ones have the corrosion problem. Does anyone know what the factory used? I am assuming that the small ones were used by a PO as a repair but am not sure. The photo shows a good small rivet and a spot about 4 inches away that used to have a large rivet; other large ones are in somewhat better shape.

I plan to make some 1 inch diameter aluminum washers to get beyond the corroded area. If anyone has any thoughts I'd like to hear them. (I know that this will be a less than ideal repair, but I don't think a full belly pan replacement is warranted at this time.)

Thanks for any advice/experience.

Whit Nash

[Wingeezer]

I've had a lot of problems with corrosion of the belly pan on our trailer. I think a lt of it is attributed to the fact that we haul it south each winter, starting out over wet and salty roads.

Even though I try hard to wash it when we get to our Southern destination, my belief is that salty water gets up int the belly pan one way or another and cannot be washed out. Even when the water dries, the salt residue is left behind and every time it gets wet again - even in summer - continues its evil work!

The situation is exacerbated because the aluminum belly pan is riveted to steel cross members setting up an ideal situation fr galvanic corrosion, much encouraged by teh presence of the salty water!

Last winter when we headed South, I went prepared to try to deal with it. I replaced over 100 missing rivets in my effort to ensure that the belly pan sheets would remain with the trailer!


I took a small air compressor with my along with an air/hydraulic rivet gun (not expensive.)

I drilled and replaced rivets with larger 3/16" diameter ones - these can be a bit of a bugger to install with a hand riveter if you have a lot to do and have arthritis problems in the hands,
but they are quite a bit more substantial than 1/8" diameter rivets.

As well, I bought three foot lengths of 1/16 or 1/8" by one inch aluminum strips from Lowes and cut them into one inch square washers and used one with each rivet.

A good cordless drill along with the air/hydraulic rivet gun (only about $50 - try Harbor Freight) made the job almost fun!

I'm sure it will be an on-going project, but at least for now I think I am safe from losing belly pan sheets on the interstate!

Truth to tell I wish AS did not have the enclosed underbelly - our last non-AS trailer did not, plus it had a galvanised Alco frame - everything under there stood up amazingly well and everything was easily accessed.

I suppose there are some advantages to having it enclosed - retaining heat for tanks, slight aerodynamic improvement, providing a home for little critters.

[rwnash]

Wingeezer,

Thanks for your insight. Normally I would like an excuse to buy a new tool but with only about 15 bad rivets I'll see how my manual setter works with the large rivets. (I bought a nice one, Marson brand?, when I had to do some repair on my previous trailer using small head 1/8 inch blind rivets.)

I am fairly sure that the problem arose under a previous owner. Being a "fair weather" camper I don't use it in the winter and it is stored indoors while not in use. But it is possible that it did see some salt on trips south. The original owner lived in Michigan and the person I bought it from said that his seller did spend time in Florida - probably near the ocean!

I also have some doubts about the virtue of an enclosed trailer underside. It does make some repairs more difficult. I have not used an Airstream in the winter so I can't speak from experience; but doubt that it would help keep the trailer warm or the tanks from freezing.

Thanks again; UPS brought the aluminum yesterday afternoon so I have job security.

Whit Nash

[ShullsinUtah]

Any suggestions on how to proceed with a similar repair?

We hit a deer this summer and when doing a post camping season shakedown I noticed we had some loose rivets on the belly pan on the back of the trailer.

Any idea on how much a deal would charge to do the work?

Thanks in advance.

[DryFly]

You have galvanic corrosion. The belly pan is a thin sheet of aluminum that is in contact with a much thicker steel frame, Over time the area around the rivets will corrode due to dissimilar metals in contact and a whole lot of bouncing around.

You can find the large head rivets to replace the old ones at many outlets, including Vintage Trailer Supply. I purchased a couple pounds at my local Fastenal shop.

I eventually replaced my entire belly pan, and I'm really glad I did. It wasn't too difficult - I did it without assistance. Replacing it allowed me to get rid of the crappy, wet pink insulation, clean up and beef up the frame and a couple of outriggers, reinforce the plywood floor where it was suspect, and put on a new heavier aluminum pan.

Here's a link to a thread - I learned a lot form some very knowledgeable people on this forum http://www.airforums.com/forums/f44/...pan-97769.html

[perryg114]

Might be worth removing some skin and seeing what the frame and floor look like. There are lots of places for water to come in and soak fiberglass with water and then you have two different metals and water you have the perfect corrosion environment. Many of us paint the frame with POR15 to protect the frame and create an electrical insulator. Remove the wet pink insulation and leave it out. For the short run, you can use large head rivets with washers or just make some square pieces of skin an inch or so square and use those as washers. I would seal the storage compartment where the frame cross member is and put some drain holes in, so water does not move from the compartment up under the belly. I made a separate compartment for my bumper and bolted the center skin back on.



Perry