Aluminum Frame Equipment trailer

[UPRAISER]

I was in PA last spring for one of the Mud Sales in Lancaster Co. and noticed some very good looking aluminum frame equipment trailers.

I know that a lot of large highway rigs have aluminum frames, and the weight is an advantage, and I presume they hold up well.

I have not seen equipment trailers on the road, for that matter even offered by the local dealers.

I would be interested in some feed back, problems, price etc.

Curt

 

[gordon21]

As a rule, they cost about 60-80% more than a steel trailer. Most people will not upgrade a $2000 utility trailer to $3500 to get the same size.

The obvious advantages are weight and lack of rust on the body. If you are near your towing towing limit, they may be worth the money.

Let's say you can safely pull 5000#.
A 16' steel trailer will weight 1500# and leave you with a possible payload of 3500#
A 16' aluminum trailer might weigh 800# or give you a possible payload of 4200# (assuming it is rated that high)

This lets you tow more payload, more safely than with a steel trailer.

Aluminum is fine for trailers. It just has to be thicker to give you the same strength. You can triple the thickness and still come out a lot lighter.

 

[Joe1]

Welding is sometimes a problem. The Semi's with aluminum frames have warning signs about welding, and I believe drilling as well.

 

[BTDT]

May make it more inviting to those who would rather not buy one (thieves). I don't think I've seen small utility trailers around here made from aluminum.

 

[BSVLY]

Thought I'd poist since I am in the process of purchasing an aluminum utility trailer. It will be a 10 week delivery lead time. The reason for buying aluminum is as stated above: lighter. I'm not get younger and it will be easier to handle. The car, Jeep and PU these days are smaller to save on gas and none have a huge towing capacity. So I am going aluminum to get a decent payload. I found a solid manufacturer I think. H&H

Rich

 

[keeney]

Welding is sometimes a problem. The Semi's with aluminum frames have warning signs about welding, and I believe drilling as well.

The problem with welding Aluminum is that the heat removes the temper. Your nice strong 6063-T6 at something like 24,000 PSI yield goes to "O" or fully-soft strength of around 6000 PSI (wild guess, I can't remember the exact numbers). Thats 1/3 to 1/4 the strength in the heat-affected-area of the weld. Since welds are also typically at joints where stress is concentrated, you have the weakest metal at the place of most stress - a bad combination.

Assemblying aluminum with rivets, screws, bolts, or other fasteners is typically stronger than welding it. Take a look at the aluminum skins of a jet-liner. They are riveted and screwed on with thousands of small fasteners spaced every inch or so. It would be less labor to just weld them on, but the welds would be the weak point.

The only way to get the temper back again is to put the whole wlded assmebly into an annealing oven. Not something most people are equipped to do. Maybe on ahigh-performance bicycle frame or something, but not things like truck frames or aircraft wings.

On Semi's, the structure is designed not to have any welded area that are stressed over the soft yield point. Welding a big bracket on or something will destroy the temper.

The drilling thing is mostly an issue on hardened steel frame rigs. A: Its very difficult to drill, so don't bother trying. B: You are going to generate a lot of heat burning up your drill bit, and may create a weak spot on the frame.

The other design issue with aluminum is its flex. Its only about 1/3 the stiffness of steel. Many aluminum designs are limited by un-desired flex more than yield strength. On a utility trailer with equivalent "strength", it will feel like its made out of rubber compared to the steel one. Also, the flexing can cause stress concentrations in un-anticipated places, and also magnify resonance and fatigue issues. To make the aluminim design as stiff as the steel one requires different shape sections. If your steel trailer has a 4x3/16 channel frame member, you probably want something like 6x1/4 aluminum in its place on the aluminum version.

- Rick

 

[machmeter62]

The problem with welding Aluminum is that the heat removes the temper. Your nice strong 6063-T6 at something like 24,000 PSI yield goes to "O" or fully-soft strength of around 6000 PSI (wild guess, I can't remember the exact numbers). Thats 1/3 to 1/4 the strength in the heat-affected-area of the weld. Since welds are also typically at joints where stress is concentrated, you have the weakest metal at the place of most stress - a bad combination.

Assemblying aluminum with rivets, screws, bolts, or other fasteners is typically stronger than welding it. Take a look at the aluminum skins of a jet-liner. They are riveted and screwed on with thousands of small fasteners spaced every inch or so. It would be less labor to just weld them on, but the welds would be the weak point.

The only way to get the temper back again is to put the whole wlded assmebly into an annealing oven. Not something most people are equipped to do. Maybe on ahigh-performance bicycle frame or something, but not things like truck frames or aircraft wings.

On Semi's, the structure is designed not to have any welded area that are stressed over the soft yield point. Welding a big bracket on or something will destroy the temper.

The drilling thing is mostly an issue on hardened steel frame rigs. A: Its very difficult to drill, so don't bother trying. B: You are going to generate a lot of heat burning up your drill bit, and may create a weak spot on the frame.

The other design issue with aluminum is its flex. Its only about 1/3 the stiffness of steel. Many aluminum designs are limited by un-desired flex more than yield strength. On a utility trailer with equivalent "strength", it will feel like its made out of rubber compared to the steel one. Also, the flexing can cause stress concentrations in un-anticipated places, and also magnify resonance and fatigue issues. To make the aluminim design as stiff as the steel one requires different shape sections. If your steel trailer has a 4x3/16 channel frame member, you probably want something like 6x1/4 aluminum in its place on the aluminum version.

- Rick

I don't know if this is new type aluminum welding or not, anyhow, the FAA is allowing the new VLJ's (very light jets) that are pressurized in flight to >7#/PSID; welded skin with the "stir welding" concept, replacing rivets to save manufacturing costs? It doesn't yield any strength? Could this be used for trailers also?? I think it is a semi-automated process too?

 

[shaley]

Friction stir welding (FSW). Material doesn't reach the melting point hence the full strength welds. The downside is it is better suited for thin metals and there must be a backup anvil under the joint during welding. Definately an aerospace process but it may find its way into trailers.

 

[jayhaitch]

Keeney: excellent post! That explains what I thought was odd welding on my new trailer. I bought an all aluminum 7.5x12 tandem axle landscape trailer, Continetal Cargo, by Forest River. This link is the single axle pic.

Continental Cargo Cargo Trailers by Forest River
Continental Cargo Cargo Trailers by Forest River

I couldn't figure out why the diamond plate sides were only welded in 2 inch strips every foot or so. I thought it was cheap/sloppy/faster. Now I know why. The aluminum gate does flex a bit. I was thinking of getting a welding shop to weld in one more set of cross braces, but now I think I might just bolt them in myself. I haven't noticed any flex of the trailer itself during towing.

 

[jayhaitch]

BSVLY: H&H make an excellent trailer. They were my second choice, but didn't have a tandem axle aluminum version. It really came down to a steel H&H, or this aluminum Continental Cargo trailer. I picked aluminum as I hate rusty trailers, and it will be stored outside most of the time.