Pros/cons of aluminum tub on steel frame?

[RufusTheDufus]

I'm mentally building a 4wd trailer. Soon I plan to start scribbling a design out on paper.

I'm leaning towards an independent airbag suspension with shocks running on 33 x 9.5s to match the tires on my Cruisers. I'm planning to use a steel frame and possibly aluminum for the tub and essentially everything else. I'm primarily interested in aluminum for the weight savings and keeping the center of gravity low on the trailer.

I searched here and didn't find anything related to using aluminum in trailers. Are there any disadvantages to using aluminum other than cost? I can weld aluminum so that's not an issue. I'll have to bolt the tub to the frame somehow but I kinda view that as a benefit. I can always remove the tub in the future in case I want to use the base for something else. I'm sure I'm overlooking something but can't think of it at the moment.

 

[LDowney]

The combination of Aluminum and steel would have a galvanic reaction unless precautions are taken. If properly done, the problem can be avoided.

 

[RufusTheDufus]

Good point. I didn't think of that. I'd most likely paint the frame with Rust Bullet or something similar but that won't prevent rust on the inside of the tubing.

 

[titanpat57]

Man...that sounds like an awesome build. I love aluminum...just don't know how to work with it all that well. I'd maybe consider some kind of strips of rubber between the two surfaces to protect from that reaction that happens when the two meet.


The weight you save on the tub will allow a bit more storage weight....and we all know the more you can carry the better!!

Good luck, I'll keep watching

Pat

 

[RufusTheDufus]

I'd need to isolate the bolts that hold it down with nylon or rubber bushings too. I think car manufacturers mount aluminum radiators this way.

 

[KY854RUN]

Hi Rufus,

We have this same problem in aviation. It is called dissimilar metal corrosion. It is more of a problem when there is moisture present and a bigger problem when salt water is involved in the process.

If the frame and tub are properly painted, this will not be a major problem. If the frame had something like Hurculiner, but without the chunky particles in it, it would help prevent this problem. The real key to keeping this corosion to as small of a problem as posible, is to make sure that there are no places for water to stay for any length of time. Basically, this means that you will need to clean all of the mud from under the trailer after each trip. Thuroughly rinsing the trailer with fresh water after each use greatly reduces the chances of corosion from occuring.


The nylon washers under the bolts is a great idea. But, make sure that you use a friction lock nut on those bolts because the nylon washers will allow those bolts to turn more easily from road vibration.

Kevin

 

[John E Davies]

Go for it! As long as you keep it clean and build it with dis-similar metal issues in mind, you will be happy with the result. If you want to keep it looking nice, avoid towing during winter if the DOT uses chemical deicers, and store the trailer indoors if possible.

Soft Road Trailer

John Davies
Spokane WA