I'm replacing the subfloor in my Airstream and at the back corners of the rig there is so little holding the floor to the shell that I'm considering adding a couple of corner pieces to my frame. Has anyone done this before?
The 2 farthest back outriggers don't reach the C-channel and the hole for the water heater removes a lot of the shell-to-floor strength. In addition, there is a weak bar just under the back C-channel that is the only place they bolted through the frame into the C-channel (2 bolts!) and it has a hole for the wiring drilled through it that removed half of the strength of the bar. Even though the frame runs under the C-channel, they didn't bolt through it either.
I call it "factory-direct rear-end seperation". Courtesy of the good folks who modified the design for 1964 without looking at the whole picture.
Please take a look at the PDF below and let me know what you think.
I can't see putting it back together the same way it was!
As long as it isn't too heavy I can't see how it could hurt. The design in 63 isn't much different. I made a point of replacing the rear strap that the body mounts to with angle iron, versus the flat stock it had before. Meant losing a little bumper storage area but took a lot of stress away from the two frame rail bolts having to virtually hold the entire rearend up (since the 1/8" strap was butt welded w/broken welds and would have flexed anyway).
Scott & Megan
WBCCI #8671 Oregon Unit
63 PARTS NEEDED
Tappan range oven (for spare parts)
baby moons for stock rims with clips
twist drawer knobs and their face frame screw in hook
Thanks guys, I hear so much about not adding weight to the back end that I worry about it. It is a weak spot in the construction, to be sure. I looked at this and checked it as well as possible before I started into the tear-down, and I couldn't tell that the rear end was totally seperated. I even took it to Big Sur and noticed nothing at all wrong with it.
I will be having these parts made at a local metal fabricators shop. If anyone is interested I can post the layout of these parts for others to use.
Keenly interested for my Globetrotter. I had no idea that the rear was in such dire straits either. You mentioned in another post that the black tank was enlarged. Did the PO (before me of course) simply fuse onto the side of the existing tank or replace it with a larger one. As I use my GT more and more I find that black tank to be all too small. Also, how are you plumbing in your gray tank?
I would like to stop by either this weekend or next to see just how the project is coming along and perhaps learn a little insight for when I tear apart my flooring. Let me know which is best for you!
The design is such that, other than at the intersection of the main frame rails abut the front and rear shells, the frame holds the plywood and the plywood holds the shell. The real concern is to design a system that keeps the plywood intact. Sandwiching the edge of the plywood between two metal sheets will likely cause any moisture to remain longer than without. This will cause the perimeter of the plywood to rot sooner.
A former room-mate of mine is a park ranger and they swear by this stuff whenever they are putting wood in contact with soil. It can be a bit malodorous, so I would definitely be sure it is fully dried before installation.
You are on the right track. The fear of adding "too much weight" to the back of an Airstream stems primarily from the inadequate frame they used from the getgo, and thus causing separation.
You can get a trailer so tail heavy that it goes unstable and wants to fishtail when you tow it. But, that's not what we're talking about here.
Rather, Airstream tried to keep their trailers so light that they skimped on the frame. Well, maybe "skimp" is the wrong word to use....but the thin frame they used on the short trailers isn't deep enough for the longer ones, and they used the same frame on all of them back in the day.
A few additional brackets or doublers back there won't hurt a thing.
On my '77 Excella 500, it had a 4" deep main frame. It sagged and separated. I'd designed a new frame for it that was seven times stronger (a little extra depth goes a LONG way). I have the CAD files for it. But unfortunately I didn't have the time to build it, so I sold the trailer and bought an '87 Avion that already had an 8" deep frame. Avions don't sag.
But anyway, the 4" frame works OK on the shorter trailers. But it wouldn't hurt to add a little additional back there. Just don't crank the heat up too much on your welding machine or you'll burn it up. Use a lower amp setting, probably like 80 amps or so, and you should be good. It's pretty thin. Really, for just the brackets, I'd TIG it and use something like 60 amps.
I thought that my tank had been enlarged or changed at some time because the box it sits in was totally remade out of aluminum diamondplate, and the bellyskin under the tank was done in the same stuff. It turns out that the tank is original. It's only about ten or twelve gallons, I think.
I will put in a tank from Inca plastics, in the frame bay just behind the axle. It's just the right size for one they have, and the dump valve will be right behind the streetside wheel. This will be graywater only and the existing tank will be for black only.
I would stay away from copper green for interior work. I just don't think it is that safe. I used 5/8" exterior siding with lap joints already cut in. I painted the underside with waterbased floor finish, and after cutting the pieces to fit, I primed and painted the edges and a few inches of the top surface which tuck under the channel.
I will be going to Las Vegas this evening, Todd, but I would like to get together next weekend.
The original construction had bolts through every full-length outrigger, going up through the plywood and into the C-channel. The short outriggers at the front and back don't reach the C-channel. they are about 2" short. At the rear end the frame goes under the C-channel but is not bolted to it. Between the two frame channels at the back there is a 1/4" x 2" flat steel bar spanning the distance, and this is the only thing with bolts in the entire back area. The rest is screwed to the plywood only.
The result is that I have about 6 woodscrews and 2 bolts holding the rear end up for the back 4' of the trailer. With almost every heavy item concentrated at the back of the trailer I could not trust this construction again.
I agree fully about the plywood being very important to this system, and I have addressed that as much as my finances will allow, which is a lot better than original. My issue is that using the plywood, almost exclusivly, to hold the thing together is a temporary situation at best.
I want to attach the C-channel to the frame all around the back, if it won't cause additional issues to develop later.
Jim, Thanks for the welding information. I was going to have to ask that question soon. You saved me the time.
Thanks for your input. I do appreciate it.
I suspect when I remove the floor on my 64tw I'll see a similar setup to yours, do you have any photos of the actual repair you did between the last outrigger and main frame rail? Also did you beef up the flat stock in the rear between the two main frame rails?
This pdf shows what I had in mind. I couldn't afford to have a fabricator make these for me so I made them out of 1-1/2" x 1-1/2" angle iron. They are shaped to follow the C-channel in the wall and bolted through the C-channel, plywood, and angle iron. They could have been welded to the frame but it doesn't seem necessary. The weak points here are the bolts and screws that hold down the C-channel to the floor. The bolts had loosened and with the movement of the shell they had beat up the holes in the C-channel until the holes were bigger than the bolt heads. The wood screws were rusted completely away. This metal piece creates a sandwich of metal and plywood that ties the shell and floor together much better than original. The stresses were transfered to the floor hold-down bolts that go through the frame rails and outriggers which are stainless with fender washers, lock washers, and ny-lok nuts on the bottom. Each of these angle iron pieces got five bolts through them, the floor and the C-channel.
I left the flat steel strip in between the frame rails at the back as-is. It was intact and in good shape, and the changes I made make it redundant.
Total cost: about $25