Steel Tubing under the Alum Walls

[big-boss]

Ok- I first thought I had no if only little floor rot- boy I am I dumb. Sombody went in and leveled the floor with grout good idea.

Anyway, just figuring out the construction: Why wouldn't I run a piece of square tubbing on top of the frame under the body for the complete perimeter? Not putting the plywood under the body. Then put plywood between the tubbing putting some tabs on the tubing to support the plywood. This seems smarter? What do you think?

[Splitrock]

Are you sure there's a frame under the trailer?

[big-boss]

Yes, maybe I am calling it wrong. Mine has the two channels with the "ribs" running out to under the plywood to under the outside of the perimeter. The alum channel of the body is bolted to the ribs through the plywood.
I was thinking of wrapping a piece of rectangle tubing all the way around under the alum body channel.

[Aerowood]

It would not keep the plywood from rotting but it would definatly keep the body from sagging if the ply should rot. Are you talking square tubing. and do you think you could bend it around the corners? I like the idea

[Dave Park]

It has some advantages and some disadvantages.

Advantages:
...

Disadvantages:
Rigidity: the floor is an integral member that distributes the body's load on the frame and detaching it from the walls places all the loads on the spurs without the wood carrying any of it further inboard. Also, the wood can flex, which is an important stress-absorbtion method.
Corrosion: steel and aluminum are a bad combination - both materials would need to be coated/treated to prevent metal on metal contact. Some people discount it, but these trailers last so long you need to think in timescales of geological time
Non-conformity: Your trailer will be different from everyone else's, in a hidden way. Future maintenance by someone not knowing the unique construction of your trailer may cause a hazardous condition.
You have to do it: You have to be the first person to figure out the methods to make this piece of metal fit the situation, and to be the first to find how the weaknesses affect the next forty years of your Airstream.

[Kevin245]

Originally Posted by big-boss

Yes, maybe I am calling it wrong. Mine has the two channels with the "ribs" running out to under the plywood to under the outside of the perimeter. The alum channel of the body is bolted to the ribs through the plywood.
I was thinking of wrapping a piece of rectangle tubing all the way around under the alum body channel.

How about a few photographs of existing conditions and the area in question?

Kevin

[big-boss]

I am practicing with pictures, why is that almost evey site is different?

I will post some tonight. I am thinking very hard. I am sure I won't be the first to have ever done this.

Thanks

[mello mike]

So contrary to your profile, it looks like you're no longer looking. What year and model is that?

[big-boss]

I haven't figured out how to change my profile. I also haven't figured out how to add gallery pictures. So I am still on it.
Anyway, it is a 1961 30 Sovereign Land Yacht International. It is in fair shape but I got it for scrap value. Has been sitting for last 20 years used as a house then mothers house then crack den then storage. I have gutted the entire nasty interior out never found enve a penny and all the copper wire was stripped clean- that is why I know it was a crack den. It tows great even with dead tires. Little more work than what I really wanted or needed but it has a cool factor.

[Dr Dan]

I was thinking the same thing about the tubing, but was thinking aluminum tubing with aluminum bar stock running all the way across across to allow for plywood to drop in flush for the floor. It would sure make a floor change out one heck of a lot easier, would eliminate the wicking of moisture into the floor through the end grain of the plywood, and I would think still allow for the floor to flex. You could isolate the aluminum tubing from the steel out riggers with rubber or some other non conductive material as far as dissimilar metal corrosion is concerned. I don't read much about using treated plywood. Is that because of the lead and arsenic eating up the other metals? I know you cant use galvanized hardware with it, but There is some other treated hardware you can use.

[big-boss]

Call me crazy but I am doing it. I will get pictures in next couple of days.

I am using 5/8 x 1 1/2in alum bar. Then I am attaching an 1/8 x 1 1/2in bar under that to secure the plywood. It will add about 80 lbs but I beleieve it will really pull it together and make the floor way too easy. I can also build out the inside in luxury -Tanks plumbing and all that from the topside.

[Aerowood]

Cool, how do you plan on making the corners. I'm kinda surprised that you are going to use aluminum bar stock. The use of 3/4" X 1 1/2" square steel tubing would allow the stock to be welded on, along with the floorboard mounting flange. Steel would be alot cheaper, lighter, and could be heated to bend around the corners. Use of a 3/4" over 5/8" thick stock would also allow use of a 3/4" plywood floor, that I feel is much more firm then the 5/8" ply.

As far as aluminum to steel corrosion issues, a good epoxy primer on both mating surfaces and then sealing the two mating surfaces with a quailty sealant is more then adequate to prevent galvanic corrosion.

[truckasaurus]

I'm planning on a similar approach for my next trailer so will be following along keenly. (I'm thinking of the steel tube versus aluminum, but the same concept).

[big-boss]

The weight is only about .12 more lbs per foot and a really want to stay with the 5/8 plywood. I plan on using a 5/8 in plywood used for structural concrete forms it is seven ply sealed and covered with an epoxy paper.
I am going to make a template for the four rounded corners and use the flat bar to make the corners with cutting & welding-hard way for sure. Will have to do the same for steel too. If this works out the next could water cut some 5/8 plate that would be too easy.

[Aerowood]

I can't wait to see the pictures.

[big-boss]

Man there is alot of rivits! My frig wouldnt fit out the door so I cut the door off. What is with that?

[big-boss]

OK, I now have half of the floor out. What a nasty job. My outriggers were all fine seems like there was some black tar stuff over the steel. If I were to guess it looks like coal tar epoxy that we once put on water valves that get burried in the street. The bolts were all rusted to failure-suprised the top even stayed on for the trip home. I do not think Wally was thinking his trailers would be still hanging around after 50 plus years.

Does anybody know the corner radius? It seems like 20in radius to the inside.