Compound Rib Fracture

[Kiggsia]

One of the ribs in my 15 foot aluminum boat is broken in two places. After I replace the loose rivets there, I need to repair the crack. Might JB weld, perhaps in several layers, work, or must I take it to a shop to have it welded?

 

[Michigan Lakes]

I had one rib crack on my 15' aluminum canoe. The cracked rib and surrounding area was flexing approximately 1" under load. My first repair attempt was to braze it using a MAPP gas torch. This repair failed almost instantly. The second attempt involved JD Weld under a scrap aluminum brace which was blind riveted into the cracked rib. Although this repair lasted a few trips to the lake, it eventually failed as well, with the JB weld cracking and the rivets working themselves loose. I ended up using an aluminum pipe to build a brace between the thwart (horizontal cross brace connected to the gunnels) and the cracked rib. This fixed the flexing issue entirely.
I realize the fix I used on my canoe would not apply to your boat but I strongly advise avoiding JB Weld and other quick methods for fixing something that has already cracked due to flexing.

 

[Kiggsia]

You may have an idea I can use on mine, the breaks are under a seat that is mounted athwartship. as your thwart is. I could replace my loose rivets with blind aluminum rivets, and mount a brace between the cracked rib & the seat, worth a try, but I guess you would not recommend having the cracks arc welded as they may crack also?

 

[Michigan Lakes]

My working knowledge of bonding metals essentially consists of some gas welding in a college class about 15 years ago and the brazing attempt mentioned above. In a sense, I know more about what not to do in this situation as opposed to the right answer. Arc welding may very well be a good direction to go.
I did manage to find a photo I took prior to any repair attempts. This was sent out to a few home-based welders that were advertising their services on Craigslist and Facebook marketplace. None of them responded. Not sure if this was due to their understandable apprehension at the prospect of welding an old aluminum canoe or just nature of moonlight business.
Either way, the brace ended up being a pretty surefire fix for the crack induced hull flexing. I'd like to attach of a photo of the brace but the canoe remains in it's winter tarp house beside the garage. If your still curious about how the brace looks, feel free to contact me in April. Hopefully I'll be in Summer mode by then.

 

[froggy1150]

Tig weld it. They do make a aluminum stick rod (think it's dcen((direct current electrode negative )) ). I have only used those a few times. Dont think it will weld that thin of a material. You can also use a spool gun. Like a might welder for aluminum but those run hot too. Tig will give you the most control over the heat and process. Aluminum will melt out quickly and then a simple repair can suck. Find a "good" fab shop and if you do all the fitup and all they have to do is weld it might save you a few bucks

 

[Scott Danforth]

take it to a good weld shop and have it welded.

it should be v-grooved and tig welded