Aluminum Utility Trailer

[kystik35]

I am about to start on a utility trailer made from aluminum and am looking for opinions on whether im on the the right track or not. The trailer will be 16' long and 6'10" wide. Im going to use 2x5x1/8" tubing for the main frame and the tongue which will be wrapped under the frame. The x members will be 3" channel 3/16". I was planning on spacing the x members every 16" oc. Its just going to be a general purpose trailer hauling anything from zero turn mowers to utv to possibly even light vehicles. Does this sound like im on the right track?

[aametalmaster]

Yes no and maybe. I would use heavier tube for the side rails just my thought. And what are you going to weld it with?...Bob

[nervous fish]

I would consider going alittle heavier on the tubing just incase.

[walker]

From the vantage point of having seen and repaired a TON of broken aluminum junk on trucks and trailers I would strongly advise you to use steel instead of aluminum. You can cycle steel Waaaay more times than you can cycle aluminum. If you are insistent on making the error of using aluminum for a utility trailer, then pony up the cash and get some bigger heavier tubing.

[kystik35]

I realize that steel would be the stronger option but I have just always wanted to build one from aluminum. I also forgot to mention that I would be using 2x2x1/8" tubing for the top railing so that should add some extra strength. I will be welding the project with the spool gun on the 212 or dare I say a Lincoln power mig 350 with a push pull gun.

[Sberry]

I would be looking at a commercial built one to copy at the minimum.

[aametalmaster]

I still would use thicker tubing where the cross members weld in. I fixed a steel trailer this summer that was built similar to what you are describing that the 1/8" wall tube didn't hold up and caused all kinds of problems. One the spring hangers pushed thru the tube and a few cross members pulled chunks of tube out. The guy was a landscaper and i am sure the trailer was beat on a daily basis. I have some alum horse trailer pics someplace that pretty much fell apart on the frame. One it was a totally bad design and two they didn't use enough aluminum...Bob

[FernTJ]

I agree with the comments about wall thickness. Those 2 by 5 tubes will be nice and stiff and can support a lot of weight, but the joint design and welding will be critical to avoid ripping the thin wall out.

I think a deck over design would work better using that tubing than a ladder frame. That would reduce shear forces making a wall failure less likely. You would still need to have some careful thought about how the suspension attaches though.

[FusionKing]

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.

[Daniel]

You can get one already made for under $5000.
If you insist in building it I would you heavy 6" channel for main frame.

[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.