Best way to fix cracks in aluminum boat without welding

[jaclark91]

I picked up a 1436 polar kraft flatbottom boat with a gas tank and a 20hp mariner tiller motor on craigslist the other day for $300. I mainly wanted the motor so I just consider it like getting the boat for free. The boat is old, should be pre 1972 since it doesn't have a HIN on the transom, and it is pretty beat up. There are like 5-6 cracks in the bottom and I'm sure it has a bunch of leaky rivets. I have a trailer that extends to fit boats up to like 18ft so I'm watching to find a good deal on a bigger aluminum boat but in the mean time I want to use this one.

My question is what's the best way to go about fixing this one without putting too much money into it? I was thinking I would get some of those aluminum brazing rods and drilling out the ends of the cracks and brazing them from the inside of the boat, and then getting some diamond plate aluminum and making a patch to rivet to the bottom with some 5200 to seal it.

Anyone got any better ideas than this? Would JB weld or marine tex or alumbond or something work better to patch the cracks from the inside than the brazing rods?

 

[CedarRiverScooter]

Forget the brazing. Doesnt work. Just make patches & rivet them on with sealer of your choice.

 

[jaclark91]

Thanks for the advice, so you wouldn't bother putting anything on the inside of the boat to seal it? Some of the cracks are on the corners or inside dented areas so might be hard to get the patch to conform to the shape of the boat perfectly.

Another question, it looks like the handle was ripped off the front of the boat at some point and the rail was broken, what's the best way to go about fixing this? I need to put a bow eye on the front or another handle to hook the trailer winch to. I was thinking about just putting a patch of diamond plate aluminum on the inside and outside to give it strength and sealing them with 5200 and riveting them in place and then getting a stainless bow eye u-bolt off ebay and putting it somewhere in the center to hook the trailer winch to.

Not sure what to do about the broken rail if the brazing rods don't work, maybe grind the bondo off and hammer it as straight as I can and slather some jb weld on it? Here's a couple pics:

 

[lckstckn2smknbrls]

I would clean off all the crap down to bare aluminum. Then find a piece of aluminum tube that fits snuggle inside the original tube.
cut a slot in both sides of the original tube. Slide the new tube inside the original tube, align the original tubes. Using the slots move the new tube half way into the other original tube. Get everything welded up.

 

[maintenanceguy]

I've had good luck with the aluminum brazing rod on a couple of worn spots where our jon boat was dragged through the sand for years. I was patching holes that were 1/8" across in good, solid aluminum. I wouldn't use it on cracks. I don't think it would hold up to flexing and would crack again.