Aluminum Utility Trailer

[PA Weldor]

Ditto on the heavier walled tubing for your frame rails.

[Blondie_486]

OMG....not another guy wanting to make an aluminum WELDED trailer thread.
This design could even be marginal in steel with a trailer that big.
1/8th" is a joke. An anyone who knows aluminum would know that.
It will start out just great and everyone would think it was just fine.
And then over time it will simply crack to pieces. Everywhere you weld there will be no more temper. The more bracing you weld in the more crack prone it becomes.
If you are gonna use aluminum, you have to DOUBLE thicknesses over steel. And BOLT all structural members. 6" I beam would be a much better choice.
A design for steel isn't taking aluminum into consideration.
Just because you always wanted to do something doesn't justify crap. How many welded aluminum airplanes do you see?
This is why the laws need to be much stricter when it comes to trailers IMO.

Having worked for a company that manufacturers aluminum trailers I have to agree with FusionKing. I worked for a company in northeast Ohio that has been making aluminum dump and flatbed trailers since 1968 and is still in business today and is a major brand of trailer throughout the U.S.

First off forget about using tubing or anything other than an "I" beam! Depending on the weight you anticipate carrying I would say that 6" would be the minimum, I've built a couple of aluminum race car trailers and used 8" I beam for the framework.

Keep welding to a bare minimum as they are potential failures if not done properly. Most aluminum frame welds start at the crater at the end of the weld and progress from there until the entire weld is compromised. You can have no craters at the end of any structural aluminum weld. All cross members should be bolted or "Hucked" to the frame rails. Stake pockets and rub rails are OK to weld as they're not usually structural.

The suspension will have to be mounted to steel hangers which should be mechanically secured to the aluminum framework with a dielectric barrier in place, molybdenum disulphide (never seize or similar product) at a very minimum, ideally a stainless shim should be installed between the steel and aluminum. Stainless bolting material would be a minimum with "Huck" brand fasteners being the ideal choice.

Unless you have experience in aluminum trailer construction I'd stay away from such a project! If you feel that you still must build an aluminum trailer do yourself and the rest of the motoring public a favor and have a qualified engineer who is familiar with aluminum trailer construction draft a set of plans and spec out the materials needed to build a safe trailer.

Also be aware that aluminum trailers have a lifespan. After so long the aluminum becomes fatigued and is no longer viable and the trailer should be scrapped out and replaced. I've done plenty of time in landfills repairing old aluminum trailers who's axles have been literally ripped from beneath them while being extricated with a dozer.

If you get a chance go to a truck stop and observe aluminum trailers as they're being jockeyed into a parking space and pay close attention to the popping sounds they make, every pop is fatiguing the aluminum and is a potential failure point at some point in the future.

Unless you really need to save the weight so you can legally haul a heavy object consider building your trailer out of steel. You'll have a stronger and more repairable trailer which will outlast an aluminum trailer.

Just my 2 cents, take it for what it's worth.