by Fireflyinva » Thu May 19, 2005 3:06 pm
After exchanging emails with a teardropper, I decided to spend my break surfing teardrop sites. I'm a trailer type surfing through here--but the topic prompted me to respond.
I can document all-aluminimum body trailers to at least the 1930s (eg, Bowlus), they probably were made earlier. It's a form of construction also common in aircraft, so it is pretty strong. It's also how I understand Thor makes its T@B trailers. I don't know how it compares with construction costs with a wood body, but there's no reason why you shouldn't try for it.
That said, I don't think any of them have aluminum frames (trailers) on the bottom, so far as I know. They tend to be steel. Early trailers had wooden trailer frames, but again, I don't think there's any comparison to steel in strength. A rigid bed is necessary to prevent flexing, which could cause your teardrop to literally get ripped apart at the seams.
But above this, why the heck not go all-aluminum? It's much lighter than wood core construction. I'm airstream influenced, so my understanding comes from that form of construction. I'd still go for a proper steel frame trailer frame, decked with an appropriate marine ply (though I know some folks who are experimenting with decking made of the new plastic plywood thats out there now). Like most modern teardrop construction, I'd use a double wall construction, probably putting insulation in the core.
I'd start by attaching an aluminum U channel to the perimeter of the deck, attaching it with good hefty stainless bolts to the trailer frame. Then I'd shape the perimeter teardrop shaped frame with U channel, attach the outer, then the inner walls. For framing in the galley port (and maybe places where you hang cabinetry), you may want to use heavier metal for increased rigidity. Once you clad the inside and outside with aluminum, however, you will gain a huge amount of structural rigidity just from connecting the two layers with an internal aluminum frame (the U channels). BTW--structural aluminum like this can be ordered from Aircraft Spruce.
A couple of considerations--since you'd only be using aluminum, screws would not have any depth of material to gain purchase (like they would in wood). You'd have to use aluminum rivets instead. Without getting into a discussion of types of rivets (there's a whole story there), a big decision will be whether you will want to invest in a compression driven rivet tool. The manual ones are cheap and readily available, but remember, you'll be driving in hundreds of rivets, so that's a whole lot of cranking!
Another concern you must pay attention to is controlling a nasty thing called dissimilar metal corrosion. Basically, you don't want to have bare steel meet bare aluminum, because you will essentially start up a slow battery effect (no, it won't electrocute you, just corode everything). That means painting your steel frame with protective paint (like POR-15 or the ilk), using coated stainless bolts and sacrificial zinc washers.
Finally, you are looking to get a real shiny polish, you should use 2024 aluminum (aka, plated or alclad) for your exterior shell. This has a plating of purer aluminum on the surface, which will get much shinier if you put in the effort to polish it.
Mary
Last edited by
Fireflyinva on Fri May 20, 2005 4:15 pm, edited 1 time in total.
That's exactly what I did when I built mine! 
