# Aluminum hull/keel repair



## lacdown

I sustained some minor damage to the keel & hull area of my aluminum boat the other day. Took it off the water Sunday morning and water is still very slowly dripping out of the hollow keel tonight. With a flashlight it looks like water reflecting 6 rivets up. Looked into patches for the rivets but some articles said if it's leaking out of the hollow keel then trying to patch from the inside may be necessary, which I can't access due to the panels. Any advice or recommendations on a central ohio aluminum hull repair shop that is cheap yet trustworthy? I live up in Westerville so the closer the better. Much thanks in advance.


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## oarfish

What size boat? Have you heard of the product "Gluvit"?


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## lacdown

17.5 ft... i bought some 3m 5200 Marine Sealant but most sites say if it's within that hollow keel I have to repair/patch from the inside. If I can use that same material then great but I'm hoping for alternatives to taking out the platforms.


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## andesangler

My suggestion depends on two presumptions:

1. By "hollow keel" you mean a second strip of aluminum that is formed lengthwise into a U-shaped cross-section (like a length of "hat channel" or channel iron) that is riveted/welded to the bottom over the keel, to do things like protect the joint where the boat's bottom skin panels are secured together, provide a bearing surface for the keel rollers on your trailer, etc. There may be a long hollow space created inside the keel, between the metal skin of the boat and the U-shaped piece.

2. By "panels" and "platforms" you mean the false floor panels that cover the inside bottom of the boat.

If either of these presumptions are incorrect, my suggestion may change.

If you need to repair the hollow keel, as well as seal leaks, you may start with some epoxy putty. You can get sticks of it, like J.B. Weld and other brands, from your favorite auto parts supplier or marine supplies place. If the leaks are caused by actual damage to the skin of the boat (tear, crack or puncture), this can be repaired with the same epoxy putty, but it's better done from the inside. Gotta remove paint and clean well all surfaces before applying the putty.

Another option, depending on exactly what the damage is and how it is leaking, and whether you want to rebuild a possibly mashed or torn hollow keel, is to use the 3M #5200 sealant you have. That there is some serious caulk. I have used it to repair leaks in a big outdoor pool I used to take care of, and as a sealant when I rebuilt the transom on a small aluminum boat I have. If water is leaking into the bottom of the boat, and it really is coming in from a leak that is drawing water in from the inside of the hollow keel, then filling the hollow space of the keel with your 5200 should take care of it. From the outside, drill a few 1/4" or so holes 4-6 inches apart along the length of it in the damaged/leaking area, and fill with the sealant until squirting more sealant into one hole makes it ooze out the others. This may require several tubes, depending on the volume of space you need to fill. Allow the sealant a day or two to cure, based on temperatures, and then trim the excess away with a razor knife. If the shape of the hollow keel permits, it's probably better to drill through the side of the "U" than the bottom so your keel rollers won't roll across the filled holes. Of course, clean and dry the repair area very well before applying the sealant, and don't use solvents/cleaners that have alcohol in them, as it can mess up the curing process of the sealant.

Leaking around rivets is best repaired by replacing the faulty rivets. Second best is to peen them a little, but this requires hammer access to both sides (hold bigger hammer as an anvil against the head of the rivet, and gently use a smaller hammer to tap on the other end of the rivet, thus mashing it very slightly).

Welding, brazing or soldering is another option, but repairing aluminum this way is pretty tricky and requires some special skills, knowledge and gear, and depends on the particular alloy your boat is made of. If you want this, you'll need to find a shop that specializes in boat or airplane repairs. Good aluminum welding info here:

http://www.tinmantech.com/

BTW, did you find your 5200 sealant locally? I've bought it online, but would like to find a local supplier.

Be patient with your repair project, and good luck!

andesangler


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## Mr.Versatility

If the aft end of the keel strip is hollow, then PM me for a possible fix


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## lacdown

andes, your presumptions are correct. I may be overreacting to the water but I'll find out more this saturday. likely i'll end up using the 3M 5200 around some of the rivets and in the keel end... also may use your hammer technique where the keel is no longer flush onto the hull. purchased the 3M 5200 at home depot...it was by the paint section, well hidden... the store associates didn't even know about it but i spotted it out of the corner of my eye so look hard.. one tube was about $6.50. 
Thanks for the insight!


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## Mr.Versatility

You may want to go back to Depot and look for WaterWeld, made by the JB folks. This is a 2 part epoxy putty for $4 bucks and easy to use. As I said in the PM, if the keel strip that is hollow has an open end, then think of it as a large hole in the boat????

For example, Starcraft, before they corrected their self-admitted flaws in design, use to take a perfectly solid one-piece hull and punch 100 holes in it to attach this useless keelstrip.

When a disruption occurs and a few of the rivets loosen, water will seep into, and upwards into the boat, mostly from the open end of this attachment because it is filled when the boat is submersed........


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## andesangler

I had thought about using an epoxy to seal the hollow keel, but the one concern I had is how well a rigid epoxy will hold up to big temperature swings (including freezing/thawing--aluminum expands and contracts a lot with temp changes) along with bumps on concrete or rocks or trailer frame/rollers. That's why I suggested the 5200 as a "plug." That's my only concern however, and it may very well be unfounded.

Very good price on that 5200! I paid twice that to some marine place in Pennsylvania about two years ago. I think I'll have to go get some and set it aside for my next repair job.

Let us know how it goes.

andesangler


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## Mr.Versatility

The secret to YOUR success.....................

Fill the entire hollow tube with silicone caulk in a ramrod method, then make the PLUG with waterweld by JB, then weather is not an issue


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## oarfish

Epoxy works with aluminum very well.
I never had problem. That 5200 product is a bogus I would not evem use it in my shower. Check out the " gluvit" for minor leaks.
Major leaks weld or use epoxy.


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## Mr.Versatility

oarfish said:


> Epoxy works with aluminum very well.
> I never had problem. That 5200 product is a bogus I would not evem use it in my shower. Check out the " gluvit" for minor leaks.
> Major leaks weld or use epoxy.


Not accurate.............

Gluvit is fantastic, but the laws of gravity insist that some is applied from the inside as well as converting your hull to glass from the outside, and sanding and priming and painting, and this guy ain't yankin his floor or peening any rivets!!

Never weld a riveted boat because the gasketing between the connections will FRY!!

Think outisde the box!! Think of your hull as a spoon. You want that spoon one SOLID PIECE


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## oarfish

Mr.Versatility said:


> Not accurate.............
> 
> Gluvit is fantastic, but the laws of gravity insist that some is applied from the inside as well as converting your hull to glass from the outside, and sanding and priming and painting, and this guy ain't yankin his floor or peening any rivets!!
> 
> Never weld a riveted boat because the gasketing between the connections will FRY!!
> 
> Think outisde the box!! Think of your hull as a spoon. You want that spoon one SOLID PIECE


Gluvit works from the outside just as effective. I would only weld where there is no seam packing to burn out. I would rivet patch major cracks by the seam instead of welding. Gluvit will not show on paint as much as caulk in outside application but easy to paint if perfect looking boat is the goal.
5200 caulk could work but will more likely to separate from aluminum than epoxy or even poly resin. The biggest myth is that poly resin is rigid and will not flex along with aluminum.


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