Welding Aluminum Trailer?

[Bob]

My aluminum trailer has developed cracks in the main lengthwise I beams. They are about 12 inches long between the base of the I and the vertical section of the beam.
The transverse member that holds the forward ends of the bunks is attached at about the place where the cracks developed. Can they be safely welded by a competent welder or do I need to replace the aluminum channels? Opinions? Experience?
The trailer is rated for 2000lbs more than the boat weight?!! Thanks for the help.

[Forrest]

I wouldn't try to weld it. It probably broke due to fatigue and most likely the aluminum I-beam is a 6061-T6 extrusion which means that it's heat treated as it drawn through the die when it is made. Excessive heating of this type of aluminum by welding greatly weakens the surrounding area. To make matters worse, aluminum I-beams trailers do a lot of flexing while going down the road. For peace of mind, I would say that it's time for new I-beams or maybe a new trailer.

[MOP]

Don't want to start another Brew Ha Ha but one of my local boat haulers had his alum trailer crack last year. I remembered that and finally got over to inspect it to see if it developed any more cracks, it has not. The trailer is a triple axle I beam he hauls enough boats to keep him in nice cars etc IE: a lot of boats. I have seen 30+ and 25- on this trailer. The trailer was welded by our local shop with the overlays being about 8" past the cracks, the welder was an X Navy welder which I know are the best welders. Anyhow knowing what that trailer goes through I would weld it just find a good shop with a Navy boy on the machine.