Aluminum brazing repair for aluminum canoe?

[bark-eater]

I brought home a Sears aluminum canoe today. The price was low enough that I stopped looking for problems, and didn't notice a little tear until I got home. Duct tape would certainly work, but I'd like to try a more permanent fix. Has anyone here used a low temperature aluminum brazing rod and a MAP torch for this kind of thing? I have a little john boat that also needs a small repair, so I'm kind of interested in the technology.

 

[Jim Dodd]

I've watched videos, they make it look easy ! I have some rod, but haven't tried it yet ! Maybe practice on something else first ! I think the trick is getting the temp of the item hot enough to melt the the rod. Probably a good idea to clean up the aluminum good before starting.

Good Luck !

Jim

 

[memaquay]

I took a an evening welding course once when i worked on the farm. I didn't do very well, and aluminium welding was really, really hard. However, regular six ounce glass and epoxy will stick pretty nicely to aluminium if you want to make a little patch. If there is a hole, you could fill it first with jb aluminum weld, or something like that. Do the inside and the outside, it will be bomb proof.

 

[Guest]

The trouble with brazing aluminum is unlike steel it doesn't glow increasing red till it melts--it just crumbles unexpectedly leaving a bigger hole. it can be done well with practice. Maybe take it to a welding shop that welds the stuff? Also, some aluminum canoes are tempered(Grumman's for one). Welding might ruin that.

 

[forest runes]

Aluminum canoes are tempered to be mallable, once welded become brittle & prone to greater cracks, Memaquay hit the nail on the head, rough up the metal with sandpaper and repair inside and out with grey JB epoxy. As close to a permanent repair as you'll get.

 

[Guest]

https://www.westsystem.com/aluminum-boat-repair-kit/

https://www.youtube.com/watch?v=DjO-QufNd6o

 

[bark-eater]

The tear in the canoe is 1 1/2" long and above the water line, so if brazing doesn't work, an adhesive repair of the repair shouldn't be a big deal. From the little research I did, there are a couple different types of rods available. I just need to sort out between the carny soldering beer cans and the Lamborghini approved advertising. I will report back on how it goes.

 

[bark-eater]

I found another issue with the canoe. There is a strip of aluminum on top of the keel join, inside of the hull. This has a number of corrosion holes. I am assuming there is a layer of some sort of bedding compound underneath. I think water or salt water sat in the the boat and wicked into the joint. It looks to be a non structural issue, and I'd be surprised if it leaks from the out side. Because of the bedding compound I will not use a torch and brazing here, so Epoxy might be the best option. Of course I will probably just use concrete crack repair caulk, which as far as I can tell is grey 5200 at 1/3 the cost.

One bit of trivia I learned about working Aluminum, is that it oxidizes very quickly, as in seconds count, so what ever you want to to stick to it has to be applied immediately after cleaning/abrading the surface down to new metal. I've used west system acid etch for epoxy repairs on aluminum before, but didn't get a chance to see how they held up long term in a marine environment.

 

[Guest]

I once riveted a patch to the inside of a big tear and used sealer in between. I used some waterproof rivets-don't remember where I got them. Worked great.

 

[bark-eater]

I'm kind of intrigued with the idea of making an invisible repair. In general it is in very good condition, and it took me a while to find the flaws. There is a bit of denting on the bottom amidships which I should be able to push out but besides that the hull is smooth enough to take a buffer to. My inclinations are tempered by the knowledge that this canoe is fated to be chained to a tree somewhere Down East.

 

[Guest]

After patching the interior, I smoothed the outside and filled the tear with silver epoxy and sanded it smooth--almost unnoticeable repair from the outside.