A Different Idea

[JimGolden]

Hi All,

I'm considering replacing the floor in my Excella. From reading many of your excellent posts, I've gleaned quite a bit of info on the subject. I wanted to throw out a couple ideas to see what people think of them.

From what I've seen, it looks like the plywood goes across the top of the frame in a flat plane. then the steel channel is bolted through this plywood into the outriggers. The belly pan is then riveted to this channel, and the upper shell comes down from above and rivets through the side of the belly pan and into this channel. Is this correct?

Now, what I was thinking was this: Rather than replacing the plywood all the way out to the ends and redoing it just as Airstream did it, why not do the perimeter out of something that will not deteriorate, and run the interior plywood out to meet this perimeter? One example would be to use 5/8" thick aluminum bar. I'm unsure of the dimensions of the channel that rests above it, but assuming a 4" wide bar of aluminum that's 5/8" thick and running around the perimeter of a 31" trailer, I'm looking at something on the order of 250lbs added. Not a big deal. Aluminum bar of this size would be complete and total overkill, but it would never deteriorate.

Another suggestion I saw a fellow posted was to use Trex plastic/wood composite. Rip a Trex 2x6 and you're left with pretty much a 5.5" wide by 5/8" thick (after subtracting out the thickness of the saw blade) plank. If you don't need the strength of the aluminum plate, if the Trex is only serving as something to hold the channel off the outriggers and is only loaded in compression, I'd think this would work fine. The rest of the floor could then be done in plywood sheet. If it ever needed replacement, you could do it without having to tear off the shell.

At any rate, if I do remove the shell; it's a job I only want to do once. I want to make the repair as good as I can.

What do you think of my ideas? Any reason not to do it like this? The only negative I could think of is that the perimeter and the plywood center wouldn't be rigidly connected. But, you the edges could be cut on a bevel, or tongue and grooved, so that the plywood center would bear upon the edge of the perimeter material.

Thanks,
Jim

[markdoane]

That sounds similar to JohnG's proposal a little while back. http://www.airforums.com/forums/showthread.php?t=13045

[CanoeStream]

Jim -- An honest and sincere welcome to fresh ideas! Welcome to the Forums!!

Without having particulars on density, I suspect Trex and sound attachment to floor would subtract big numbers from the trailer carrying capacity. The frame, plywood floor, outer skin, and inner skin are interdependent to provide full strength to the monocoque construction. Segmenting the perimeter from the floor could call for some new engineering -- which must add weight and new potential problem areas.

Only one of the three significant floor rot areas in my Argosy were specifically attributable to the perimeter of the floor. If the P.O. (previous owner) had paid careful attention to breakdown of integrity of perimeter seal, I'd have been saved my one remaining floor problem. My other problems were related to a failed fixed window seal allowing water into a hidden floor area and a battery compartment design that allowed leakage, total floor failure and rusting away of an outrigger underneath this area.

I and many in these forums have used epoxy Rot Doctor to penetrate perimeters of new floor projects. That only delays damage. Quite a number of sources have been identified for water penetration. Paying significant attention to seals and past damage from minor dings is a never ending pursuit. I'm not about to destructively analyze how my Safari is put together from the outside, but I am going to understand how to access under-bed, under-couch, under-cabinetry and behind-appliance areas for inspection.

[JimGolden]

I read the link attached to the post above. That person was getting a little elaborate compared to what I wanted to do. He did have a good idea though that I think may be the ticket.

I still don't know how wide that C-channel is, and I'm not sure of the plywood thickness. I've seen both 5/8" and 3/4" posted here. I've not actually drilled a hole through mine to measure it (interior is still in the coach). But for discussion's sake, let's call it 5/8". As well, let's say the channel measures 2" wide.

Some aluminum sheet, say 1/8" thick by 4" wide could be laid down all around the perimeter. To this, a 2" wide bar of aluminum that is 1/2" thick would be placed along the outside edge. The effect would be a 5/8" spacer all the way around the outside perimeter for the channel to bolt through into the outriggers. In additon, a 1/8" thick by 2" wide lip would now exist around the inside of the new perimeter.

When replacing the plywood, you could route out (or not; probably wouldn't need it) 1/8" of the thickness all the way around the outside edges. The edges of the plywood would sit on and could be fastened very solidly to this perimeter aluminum plate.

The dimensions might have to be varied a bit, I believe this would give you back pretty much any rigidity you'd lose by not running the plywood out to extreme perimeter as it was originally.

From what I've seen, the plywood does hold up pretty well, all things considered. My biggest thing would be to have the ability to replace it without having to remove the shell. I think a mod like this would allow that if a future floor change were needed. As well, I don't think it'd break the bank, so to speak, as redoing the entire floor in aluminum would.

The hot ticket would be to do the floor out of aluminum/composite honeycomb. When I used to work for Boeing, I'd go down to the Boeing surplus and buy all manner of exotic materials for pennies on the dollar. I bought some 777 compression stringer for $3/pound that Boeing probably paid $100/foot for. It was 7000 series aluminum and so had a strength of about 75,000psi; double what a normal car's steel frame is. They always had lots of the honeycomb panels down there for cheap. Can't go there anymore since I moved back to WV. Anybody out there in the Seattle area that wants some good deals on aluminum, that's the place to go.

[Jim & Susan]

Here's an idea that kinda like yours, sorta. Not the same as Boeing would do it, but a good idea none-the-less.

http://www.airforums.com/forum...ad.php?t=14620

[87MH]

Originally Posted by Canoe stream

... The frame, plywood floor, outer skin, and inner skin are interdependent to provide full strength to the monocoque construction. Segmenting the perimeter from the floor could call for some new engineering -- which must add weight and new potential problem areas.... other problems were related to a failed fixed window seal allowing water into a hidden floor area and a battery compartment design that allowed leakage, total floor failure and rusting away of an outrigger underneath this area... but I am going to understand how to access under-bed, under-couch, under-cabinetry and behind-appliance areas for inspection.

Canoe stream's post should be required reading of ANYONE anticipating a purchase of an "older" Airstream....

If you don't tear it apart for a REAL inspection, you don't know what's there.

[malconium]

Jim,

The channel is actually made out of aluminum and is in the range of 1-1/2" wide. You are pretty much correct about how the belly pan and walls attach to it although I found that the belly pan (actually the banana wrap part between the belly pan and sides) sometimes seems to attach on the outside of the body panels. The channel also has both the U on the top and a C on the bottom that slips over the edge of the plywood floor. The c-channel part makes it much harder to do a full shell off since the body will not lift off of the floor if it is still attached to the channel. Older models do not have the c-channel on the bottom of the u-channel so the body can more easily be lifted of with detatching the body panels from the channel.

In my 1973 model the plywood is definitely 3/4" thick. I may be wrong but I think it is only older models that have the 5/8" plywood.

I did all of my floor replacement without removing the shell and felt that it was a perfectably acceptable thing to do. I also did not remove all of my belly pan. I used Polyboard instead of plywood. The pointer given earlier points to a post that describes my technique in some detail. I am still happy with the results but I have not yet had time to finish the remodeling of my rig so I do not have road experience with the approach. I originally thought that I would like to have a strip around the edges too and there are still many reasons that I think this would work. Once I found the Polyboard and got into the whole process I was satisfied with doing the floors in one piece. It is just my opinion of course but I don't think it is necessary to do a full body off unless there are other things that drive that - such as major frame repair that needs to be done at a site remote to the trailer location. If you take my approach to replacing the floor without removing the shell then I think you will find that it is a lot more work to get everything else out of the way (cabinets, walls, etc.) than it is to replace the floor itself. In my case my AS was almost entirely gutted when I got it so that part of the work was relatively simple for me.

There are lots of ways to do an AS floor. The approach that would work best for you might not work well for someone else. Factors that influence the choice are such things as available tools, skills, sources of help, availability of materials and (the big one) available budget. For example, I am pretty handy but I don't weld so I tend to stay away from solutions that require welding.

I hope this helps some,

Malcolm

Originally Posted by JimGolden

I read the link attached to the post above. That person was getting a little elaborate compared to what I wanted to do. He did have a good idea though that I think may be the ticket.

I still don't know how wide that C-channel is, and I'm not sure of the plywood thickness. I've seen both 5/8" and 3/4" posted here. I've not actually drilled a hole through mine to measure it (interior is still in the coach). But for discussion's sake, let's call it 5/8". As well, let's say the channel measures 2" wide.

Some aluminum sheet, say 1/8" thick by 4" wide could be laid down all around the perimeter. To this, a 2" wide bar of aluminum that is 1/2" thick would be placed along the outside edge. The effect would be a 5/8" spacer all the way around the outside perimeter for the channel to bolt through into the outriggers. In additon, a 1/8" thick by 2" wide lip would now exist around the inside of the new perimeter.

When replacing the plywood, you could route out (or not; probably wouldn't need it) 1/8" of the thickness all the way around the outside edges. The edges of the plywood would sit on and could be fastened very solidly to this perimeter aluminum plate.

The dimensions might have to be varied a bit, I believe this would give you back pretty much any rigidity you'd lose by not running the plywood out to extreme perimeter as it was originally.

From what I've seen, the plywood does hold up pretty well, all things considered. My biggest thing would be to have the ability to replace it without having to remove the shell. I think a mod like this would allow that if a future floor change were needed. As well, I don't think it'd break the bank, so to speak, as redoing the entire floor in aluminum would.

The hot ticket would be to do the floor out of aluminum/composite honeycomb. When I used to work for Boeing, I'd go down to the Boeing surplus and buy all manner of exotic materials for pennies on the dollar. I bought some 777 compression stringer for $3/pound that Boeing probably paid $100/foot for. It was 7000 series aluminum and so had a strength of about 75,000psi; double what a normal car's steel frame is. They always had lots of the honeycomb panels down there for cheap. Can't go there anymore since I moved back to WV. Anybody out there in the Seattle area that wants some good deals on aluminum, that's the place to go.

[shannon]

What exactly is "polyboard", and what are its properties? I have tail rot and am slowly gutting the back and getting down to the floor of my Safari - er' what used to be a floor. thanks, shannon

[malconium]

Originally Posted by shannon

What exactly is "polyboard", and what are its properties? I have tail rot and am slowly gutting the back and getting down to the floor of my Safari - er' what used to be a floor. thanks, shannon

Shannon,

Check out the following thread for more information on my use of Polyboard and where I got it:

http://www.airforums.com/forum...ble-price.html

The manufactures website is:

http://newcityresources.com/pinfo.htm

It is pretty interesting stuff.

What I am finding just a little bit confusing at the moment though is that there seems to be one other company that makes a similiar product with the same name. Maybe they are just a dealer but check out the following site that I found recently when I did a web search for Polyboard:

http://www.renewresources.com/

I will be happy to try to answer any other questions you have about Polyboard once you have checked the thread and etc.

Malcolm