Crack in aluminum I beam Trailer - Fixable?

[Tin Cup]

 Greetings,

I posted this on another forum, but we have better aluminum expertise here.  

I just noticed a small crack in the bottom of my Venture I Beam trailer where the axle is bolted on. Pictures below.

Normally over the winter I block the trailer frame to take the load off of the suspension. This year I pulled the tires off to rotate, this is what exposed the crack, which I just noticed today as I was preparing to put the tires back on. For background, I bought the trailer new 16 years ago. About 4 years ago I rebuilt most of the trailer with new hardware and upgraded the axle to a 4200# from the 2800# that was original. I underestimated the weight of the boat when I bought the trailer originally, the boat weighs around 3000# fully loaded, I was definitely maxing out the original axle.

I have access to a local aluminum welder, can this simply be welded for repair? The crack does extend to the other side of the I Beam. Seems like if it cracked due to the cantilever from the axle and the rear bunk support attachment, this crack would be where the axle mounting plate ends and not over the plate. Alternatively if the rear block is higher than the forward block this would also stress the I Beam. It's hard for me to imagine that this would cause failure, however the separation of the crack on the bottom of the I beam may suggest otherwise.

I was planning to take the trailer to the welder anyway as you will notice there is another crack in the bottom of the I Beam at the end of the trailer that extends forward to under the white plastic plug. This crack was started by the vertical loading guide bar mount and it bouncing around while in use.

Thanks in advance!   

PXL_20240314_201831375~2.jpg (84.26 KiB) Viewed 558 times

PXL_20240314_201839041.jpg (124.35 KiB) Viewed 558 times

 
 
 
 
 

[gandrfab]

This seems a silly question.
Are those independent bolt on torsional stub axles or a complete axel from port to starboard?

[Tin Cup]

It's a complete axle.

[kmorin]

Tin Cup,
I'd say the aluminum trailer beam is repairable by welding but would ask if the beam/frame is adequate for the boat?  If the axle was too light for the boat, and axles notoriously match trailers in mfg.'d products' wt ratings ......  could be more wt. than the beam has the strength to bear?

I'd remove the beam, disassemble the trailer and get it available to weld- downhand not overhead.  Gouge the cracks after drilling the visible 'end' of the crack and fill the gouged/v grooved crack with weld. I'd personally do this with TIG since that's more controllable than MIG and results in better weld quality; but MIG could work.

Then, I'd want to plate the bottom flange with a 3/8" doubler and box the sides from flange to flange, say 1/4" to make the final product into a box instead of I-beam.

Stern flange crack would be relieved by the boxing side plates as well. 

Cheers,
Kevin Morin
Kenai, AK

[Tin Cup]

Thanks Kevin,

I've decided to buy a new trailer.  This trailer is overloaded and I trailer too often and too far to make it worth the risk.  

Thanks again!  
 


 

[welder]

Thanks Kevin,

I've decided to buy a new trailer.  This trailer is overloaded and I trailer too often and too far to make it worth the risk.  

Thanks again!  
 


 That is the smart thing to do.