Making a New Belly Pan...can it be done?

[aluminitus]

After removing and power washing the belly pan of my '62, it has become clear (to me, but not to my husband) that we need a new one. There are quite a few large holes that the POs cut for access. The bent part at the front and back show daylight through them and there is a clear grid of rust from the steel frame.
How hard will it be to make a new belly pan? Is there a thread that shows a step-by-step of how to do this? My husband thinks that making the curved parts will be nearly impossible.

The trailer is 21' long. What should I expect the cost for metal to be?

Any help is greatly appreciated

[purman]

What your showing doesn't look like the belly pan. Do these rap down and around and then connect to the belly pan or is it one big piece? On mine they just go down and connect to 2 long pieces that run the length of the bottom to form the belly pan.

[aluminitus]

They are part of the pan, made from one sheet of metal. The whole pan is made of two sheets, riveted together down the middle.

[purman]

You can get rolls of aluminum from a metal shop. I have no idea what the price would be. The sides should just roll up and wouldn't think there is any fabrication needed except maybe the front and back parts if those need replacing. I would take some measurements and call some metal or welding shops to see what they can get you. Shame they rap up the sides. or you could and used galvanized on the bottom. You could just rap the sides with aluminum and rivet it to a piece that then covers the bottom. That's how mine is done. It might be cheaper, and a lot easier to put in.

here is a picture of mine. I am putting the sell back on so it's not connected. The belly pan is on underneath all ready riveted to the frame. All I need to do is bend this down and around and rivet it to the belly pan on the bottom.

[Minno]

Not sure about a 62, but on our 72, the belly pan is basically 3 different pieces. There's the center belly pan, which is basically a flat piece that runs front to back and side to side to each main frame. Depending on your model, there may be sections that are lower than the rest of the belly pan. For example, to go under the fresh water tank or any waste tanks.

The sections your have circled are the side wraps. These extend from under the shell, down under the trailer to the frame, where they overlap the flat belly pan by an inch or two and are riveted to the frame. These are flat pieces of aluminum that can be easily curved to go under the trailer. No compound curves needed, nor do you need to try and pre-curve it before installation. The hard part is getting th eold wrap off, as you need to drill out the line of rivets that hold it and the shell to the c-channel. In reading some of the threads about this, the wrap may be actually wraps around the top of the c-channel making it much harder to remove from the outside. Plus, during the construction of the trailer, the side wrap was attached tot he c-channel before the shell was installed, so there will be hidden rivets you will need to contend with. Nothing a still putty knife can't resolve though. Use the putty knife as a chisel between the wrap and the c-channel to bust the hidden rivet's loose. Save the old wraps to use as a template to cut the new ones. Rivet them under the shell, using the old rivet holes in the shell as a drilling guide, using Olympic rivets and dab of vulkum in each rivet hole.

The four corner wraps are called Banana wraps because of their shape. New one are available, but only in plastic. The metal ones you have can be beaten back into shape fairly easily, and then you can use a roller to smooth out the smaller dings, bumps, and creases.

Check out some pictures at this link of our belly pan replacement:

http://www.airforums.com/forums/f185...-50967-25.html

Posts 341, 344, 350, 365, 371, & 373

We bought aluminum sheet in 5 x 10 foot and 4 X 8 foot sheets (3 of each) from a local dealer, and it cost $452. This was for a 31' trailer.

Chris

[aluminitus]

After calling numerous sheet metal places and having gotten only one or two responses, the time has come to take matters into my own hands.
But before I do, I need some advice. At the shop where the trailer is located, there are several sheets of .032 aluminum. I have no idea what the alloy composition is, and one side has white paint or coating. But they are here and cheap. Does it really matter if they are 6061 or 5052 or anything else?

[4RXLA]

Wouldn't aluminum sheet react with your steel frame and cause corrosion? I thought galvenized steel sheet is used.

[Wabbiteer]

The belly pan area itself just needs to be covered - you don't really need fancy alloys or even 0.032" thickness - 0.024 will do fine for many years. Making sure there is not direct iron to aluminum contact via frame paint or spray-can rubberized automotive undercoating blah blah will keep things healthy quite a while. The white paint side down may keep it cooler, or the white paint side up may make it last longer riveted to the steel frame...

[ddstech]

I used .025 aluminum. I want to say it was 35 dollars for a 4x8 sheet. I used six sheets because I had to put a 12 strip down the middle on both sections. Maybe I used 8 sheets to cover my 22' trailer.

[pbearsailor]

Those curved parts on the 50's and early 60's trailers are the hardest part of the job. I was really glad when they were done on my project which was shell on, as I'd assume yours would be.

I used .025 5052 on the ends and .032 on the middle section with its easier bends. You'll want to save as much of the old corner pieces as you can to use as patterns and the new belly pan slides in between the C channel and the outside skin panels. On many of the 50's trailers, the old belly pan is bent over the C channel on the inside which makes it much harder to remove. Hopefully Airstream had stopped doing that by the time they made your trailer.

You really need access to the C channel which means that the interior skins would have to come off. Much of the support for the shell is through that row of rivets going through the outside skin, belly pan, and into the C channel. Maybe Olympic rivets could be used from the outside, but I would much prefer the strength of bucked rivets.

Another issue to consider is support for the shell while you're doing the bellypan as all the rivets holding the shell to the C channel will have to be drilled out. I did mine one section at a time.

Try to read some renovation threads on 50's and early 60's trailers to see belly pan jobs. Very different on ours than was done on later model trailers with their banana wraps.

cheers,
steve

[aluminitus]

Thanks all! "Cheap and on hand" wins the day! Now to make it happen...

pbearsailor - ooo yea I know all about c-channels and shell support. This is a shell off, so access for the moment is not a problem. Fortunately the belly pan was not bent over the channel, but it sure was a pain to pull out. Glad I only have to do this once!

[Frank's Trailer Works]

It is very easy to reproduce the original belly pan using new aluminum. Use the old one as a pattern. The issue will be that now, sheets are 48" wide. Airparts inc carries anything you need. I generally use .032 5052 for bellies. I personally find .025 too thin and end up kinking it and having to start over.
There are many photos of having done this on my own trailer. Due to TOS, I cannot direct you to it, when I did it on my own trailer, Anna. I also documented it on two jobs done for clients.
Is the interior skin out? You will need to remove a lot of rivets to get the belly out. For all discussion purposes, you will be removing the entire shell, even though it can still just sit in place.
There is a another way to slip a new belly between the skin and the original belly pan. To do this, you leave a few inches of belly in place to catch the new one. It will require a new line of rivets below the floor. This is not for the intimidated. It requires forming as you go.

[65CV]

I had a really hard time with my first corner. Two mistakes -- putting rigid insulation in place first and not using enough cuts on the curve. You can see the description and embarrassing pictures here. Note posts 17 and 18, the before and after.

Patience, a good pattern, and lots of cuts and Cleo's seemed to be the secret. I still have paper patterns if you've thrown out the originals.

Good luck.

John

[aluminitus]

Thanks Frank! That is exactly what I needed to see! Should I put the shell back over the chassis and then slip the belly pan between the skin and channel or should I just put the belly pan on first, then try to make the shell fit over the whole belly pan at once?

John - Those pictures are great What a difference a day and a clear head make!

[pbearsailor]

Originally Posted by aluminitus

pbearsailor - ooo yea I know all about c-channels and shell support. This is a shell off, so access for the moment is not a problem. Fortunately the belly pan was not bent over the channel, but it sure was a pain to pull out. Glad I only have to do this once!

Sorry I just assumed you were shell on. Shell off is way easier and definitely do the belly pan before you drop the shell back on.

-steve

[Frank's Trailer Works]

what Steve said..

[VeggieBullet]

Originally Posted by ddstech

I used .025 aluminum. I want to say it was 35 dollars for a 4x8 sheet. I used six sheets because I had to put a 12 strip down the middle on both sections. Maybe I used 8 sheets to cover my 22' trailer.

WOW that was a great price....did you order online or from a local shop?

[ddstech]

Originally Posted by VeggieBullet

WOW that was a great price....did you order online or from a local shop?

I got it from a local shop. I'm probably way off on that price.

[Wabbiteer]

Nope, thats about right for a couple years back.

I nabbed 60" x 120" sheets of .032 for $39 each almost four years ago. The same place is NOW advertising specials:

.040 Painted White Aluminum Sheets 48 x 120 $69.00;
.040 Painted White Aluminum Sheets 49 x 120 $74.00
.050 Painted Black Aluminum Sheets 49 x 120 $84.00

OUCH.

[VeggieBullet]

Originally Posted by Wabbiteer

Nope, thats about right for a couple years back.

I nabbed 60" x 120" sheets of .032 for $39 each almost four years ago. The same place is NOW advertising specials:

.040 Painted White Aluminum Sheets 48 x 120 $69.00;
.040 Painted White Aluminum Sheets 49 x 120 $74.00
.050 Painted Black Aluminum Sheets 49 x 120 $84.00

OUCH.

still good prices considering that the sheets are 12ft long.
So far the best I found is $85 per sheet on 4x8 and .032 and w/o shipping