Aluminum Frame?

[BayBus79]

Nu B here so I will have lots of questions before I start my first build...

Has anyone ever investigated using extruded aluminum products
(like 80/20) to build a frame?

I think it would have some advantages: wieght, can route wires thru it,
no rust, various sizes available, etc...

Any thoughts?

[Chris C]

I don't have any experience with aluminum on small trailers, but on larger ones, i.e horse trailers and larger, metal fatigue can be a problem. I don't remember where, exactly, but if you'll do a search on this site you'll find a thread on the subject.

[mbader]

I remember seeing a comerical built teardrop with an aluminum frame.
I don't remember the brand but I think it was built in Oregon.

[emiller]

Aluminum won't bend (give) so it tends to crack at weld joints. But seams a lot of trailer manufactures are going to aluminum frames although the chassis is still steel.

[Joanne]

Nu B here so I will have lots of questions before I start my first build...

Has anyone ever investigated using extruded aluminum products
(like 80/20) to build a frame?

I think it would have some advantages: wieght, can route wires thru it,
no rust, various sizes available, etc...

Any thoughts?

Hi BayBus,

Welcome to the list!!

There have been a lot of folks talk about an aluminum frame but I've yet to see one built. I think there are two primary deterants. First, aluminum is much more expensive than steel. I don't know what current prices are but in the past aluminum prices put it beyond the reach of most of us builders. The second issue is welding. A lot of us know how to weld mild steel, but aluminum requires more skill and equipment. My MIG welder can be configured for aluminum, but I can't afford the scrap metal to practice on much less the new metal for an entire trailer.

I went shopping at the new Bass Pro Shop here in Vegas. Out front they had some big fishing boats (around 25 ft). The trailers were made of aluminum and looked really nice.

I believe that if someone is willing to pay the price for the materials and fabrication they will have a really nice trailer! If cost wasn't an issue I wouldn't hesitate for a instant to have an aluminum frame.

Now, a friend of mine just got a new Miller TIG welder....

Joanne

[madjack]

BB70...welcome to the board...as others have all ready stated, expense, fabrication, stress cracking are the problems with an Al frame...these can all be worked out so if you go for it, a lotta folks would be interested in the results...keep in mind that a properly built TD does not need a massive frame under it so weight savings in that regard would be minimal...leaving you with the cost/fabrication/cracking problems without a lot of gain for your pain...which ever way you go, take lots of pictures of your work so you can share 'em with others...including us...'cause we luv de pics....
madjack

[BayBus79]

Thanks for the quick responses...

80/20 is extruded al. strut that can be bolted together so that would remove the welding problem, (I don't weld). I'm not sure how it would handle the stress cracking problem, I know this stuff is very stiff so cracking may be a problem. Their site does a cost comparison to steel that sounds good... http://www.8020.net/T-Slot-1.asp
but I don't know.

I just didn't know if anyone had ever looked into it.

[BayBus79]

mbader you have PM

[alaska teardrop]

BayBus - Do you have a design concept of how you will build your trailer and how you would apply the 80/20 system in your construction? Fred - the worlds' farthest North teardrop builder.

[BayBus79]

no concept yet, I'm just getting started and trying to gather as much info as possible before I start. I would think it would be similar to the simple rectangle shaped frames built w/ steel, with some crossmembers. The tongue can be just like the steel frames, 80/20 can be cut at 45 deg. and bolted up.

Don't know if it's doable but I wanted to see if anyone had ever tried it...

[alaska teardrop]

BayBus, While I can perceive using the 80/20 system for framing the cabin, for a variety of reasons (some already mentioned and the cost of the individual parts) a welded steel chassis seems more appropriate. Besides, buying the equipment and learning to weld can be a good investment. Fred

[angib]

BayBus,

Looking at the 80/20 40mm sections, they are probably quite strong enough for a teardrop frame - though nowhere near as strong as 90% of folks here build their frames.

But using their bolted connections is a whole different matter - the 8mm or 5/16" bolts might be strong enough, though I'd think it was touch and go, but the way those T-nuts connect to the aluminum looks to be well below the strength of the bolts themselves. Furniture and display boards (what the 80/20 stuff seems to be aimed at) tend not to get either 'g' loadings or repetitive stresses, unlike trailers!

My guess is that if used in a trailer frame, the aluminum of the sections immediately around the fixings would suffer fatigue fairly quickly. But that is only an educated gut feel.

Andrew

[D. Tillery]

With the increased price of steel, aluminum is becomming more attractive. It looks really nice polished or anodized.

The numbers you need to be concerned with are not 80/20 but 6061 and 6063. I'd stay away from aluminum designed for show displays and office furniture and stick with those alloys designed for trailers.

Here is a great site for aluminum extrusions and components for trailers: http://easternmetal.com/products/pdfs/standards/aluminum-boat-trailer-components.pdf

Running aluminum wire through your MIG with Argon is the way to go on aluminum thick enough for a trailer frame. It is hard to keep up with feeding filler rods into such a thick TIG weld. Also, the amps required to TIG weld such thick aluminum is outside the range of most consumer grade TIG machines.

BUT I would really suggest bolting it together to reduce the chances of stress fractures. Use SS bolts to prevent oxidation.

I'd love to see some aluminum frame pics. Jealous trying to carve out enough time to get started. Other stuff just keeps coming up