Aluminum boat sealer?

[VTFan]

I have a 16 ft  aluminum flat bottom boat that has a leak somewhere that I cannot find. Just wondering what you guys think would be the best thing to seal it with? Thanks. 

 

P. S.  This boat is heavy and on a trailer. 

[Susky River Rat]

If you don’t have decking. I would try to find the leak by putting some water in the boat. Now this will only work for the most part if the leaks in the bottom. Next time you have it out try to watch to see if you see water coming in anywhere. Like a transducer jack plate etc. I have friends who flex sealed the whole bottom and it works for a little bit. The best thing is to find the leak and fix it at the source. I would use 3m 5200 sealer if it’s not a spot that is going to see abrasion. If it’s going to see abrasion you are better of trying to weld it. Sorry there is no great answer for this.

[A-Jay]

MARINE-TEX EPOXY PUTTY is a heavy-duty structural epoxy, used to repair aluminum, fiberglass and wooden boats, reinstall loose or stripped fasteners, permanently bond dissimilar metals without galvanic corrosion, and fill gouges in wood, metal and fiberglass, making repaired areas stronger than before.  Marine-Tex is an excellent choice for repairing problem areas located below the waterline. Marine-Tex is resistant to water and many chemicals.

A-Jay

[VTFan]

I do have decking. Was wondering if there is something I could paint the entire bottom with to seal the whole thing?

[Bankc]

On 5/19/2023 at 9:43 AM, VTFan said:

I do have decking. Was wondering if there is something I could paint the entire bottom with to seal the whole thing?

Flex Seal?  I have no idea how long that stuff would last in an application like that.  But they do advertise that it's made just for this type of thing.  

 

Still, I'd want to do it right with the minimum being a good, waterproof epoxy.  A marine silicone glue might work too if it's a very small leak.  But I'd locate the leak and go that route.  

 

 

 

[WRB]

Painting oxidized aluminum isn’t as simple you may think.

The boat bottom must be clean and dirt-oxide Free. Then you need a aluminum zinc-chromate primer before painting with marine grade paint.

After all this work no guarantee the leak is permanent plugged. You should find the leak source and seal it before painting the bottom.

Suggest you remove some flooring to air dry after filling the boat with enough water to cover all the bottom rivets (if riveted) or welds if welded. Look for drips on the outside hull bottom. Fix the leak with A-Jay’s suggested marine epoxy.

Short cuts rarely work.

Tom

 

[Troy85]

I found the leak on my aluminum boat and I just slapped on JB Weld on it.  Been holding so far.  I didn't know about that Marine Epoxy, if mine starts leaking again I'll probably use that next time. 

[airshot]

Have read alot about " goop" having a Marin epoxy coating with fiber for aluminum hulls as an exterior and interior coating for older leaky hulls.  The fiber is supposed to dill small cracks and holes.  Sounds good..?

[TnRiver46]

Like @Darnold335said, put the plug in the boat and fill it up with a hose. Lay under and you will see where it’s leaking. I’ve fixed holes and even missing rivets with JB weld and it’s lasted at least 10 years. Get the one that looks like a roll of coins if you can, it’s under $10 and quite magical. 
 

avoid flex seal

[T-Billy]

I sealed every rivet on my 12' flat bottom from the outside, with 3M 5200. Still good to go 16 years later. Awesome stuff.

[Susky River Rat]

1 hour ago, T-Billy said:

3M 5200.

Very good stuff 

[TnRiver46]

I also used 5200 when I replaced a transom for all the thru hull hardware. All dry 

[SproDD79]

I have 10 aluminum rowboats. Where I live once you place the boat at the lake , it's a long complicated process to move it, so if you want access to multiple lakes , one needs multiple boats. I have experienced many small undetectable leaks, leaky rivets,cracked seams, this stuff works like magic and it lasts, you just need to measure the mix correctly.

 

https://www.go2marine.com/Coat-It-Waterproof-Epoxy-Sealer?gclid=CjwKCAjwgqejBhBAEiwAuWHioEH_XC4bUMxjPH9CisBc_fb0h1PsTpltvsMpQni-Yz06xuQxvPp6MxoC-wwQAvD_BwE

[airshot]

That is the stuff I was refering to, all reviews have been good.

There is another product out there that I used on my jon boat about 5-6 years back.  Called " leak stopper" sold thru home depit and tractor supply.  It is a clear roofing sealer for all materials.  That stuff is tough, fairly thick, will plug small cracks and holes. Put it on my hon boat years back, it gets dragged over sand and rocks and stiil no leaks.  No sign of peeling up or comming loose so far..  Lots of products out there, take your pick !!

[Glenn]

Sikaflex 292i.  The stuff is bullet-proof. Once cured, the material can only be removed mechanically. 

 

https://usa.sika.com/en/industry/global-industry-content-pages-to-keep/commercial-vessels/elastic-sealing-bonding/watertight-sealingbonding/sikaflex-292i.html

 

[VTFan]

So...my brother and I jacked the boat up and leveled it then flooded the bottom with water. To my surprise there wasn't just one hole but at least half a dozen!!!  Most were just pin hole size but there were two that were pencil lead size.  Ended up getting marine grade JB Weld...which I didn't know they made. Thankfully there were no cracks anywhere.  I bought this boat from a buddy who fished it in the river... hence all the dings and holes I guess.