Aluminum Boat Repair- Will fiberglass work?

w2much · #1 September 2nd, 2006, 12:05 PM

I have some spots on my Sea Nymph that have rotted right through the aluminum hull. The boat will always be trailered not docked or in the water for extended periods. Welder advised not welding as there is wood and foam in the area. I have decided not to weld. Is fiber glass a good way to go on the exterior? I have gluvit for the interior. Will the fiberglass adhere well? Thanks in advance for your replies.

tashasdaddy · #2 September 2nd, 2006, 12:29 PM

fiberglass and aluminum expand and contract at a different rate, i think it could be a bad deal. use and aluminum patch, sealed and revited (soild rivets), then coat with gulvit.

w2much · #3 September 2nd, 2006, 12:34 PM

Would JB Weld be an option?

Bob_VT · #4 September 2nd, 2006, 01:06 PM

JB weld has NO give. Use an aluminum patch, rivits and 5200 to seal from outside or use gluit on the repair from the inside. You can even use stainless screws but coat every one with 5200 before you screw them in.

JB weld works okay on bare (lightly sanded) aluminum but it can crack from stress. If you have a rigid piece you can use it.

studlymandingo · #5 September 2nd, 2006, 01:08 PM

The patch/rivet repair reccomended by Tashasdaddy is going to be your best option. The JB weld may well pop out when the boat flexes. Is this a small crack or an actual hole?

w2much · #6 September 2nd, 2006, 01:35 PM

I agree with tashasdaddy and studlymandingo. I like the idea of a patch and stainless screws as it does not require pulling up floor and foam ( that is what I am determined to avoid). This is an actual hole. There are several spots which have rotted right through the hull for some reason(electrolisis or salt guess). I see where the JB weld by itself might pop out. I was hoping that perhaps with a fiberglass matting permeated with gluvit or epoxy it would serve to hold the patch in place with whatever was/is used to fill the voids.

tashasdaddy · #7 September 3rd, 2006, 09:29 AM

good luck, let us know how it comes out. us lots of 5200 so it squeezes out , then clean it up before it dries.

w2much · #8 September 8th, 2006, 11:21 PM

I was under the impression that 5200 was a 3M product. I went to purchase some and the NAPA could not find it in their catalog. Could you please let me know who makes it and where to purchase it..Thanks

jaymasta · #9 September 9th, 2006, 12:20 AM

Quote:

Originally Posted by w2much

I was under the impression that 5200 was a 3M product. I went to purchase some and the NAPA could not find it in their catalog. Could you please let me know who makes it and where to purchase it..Thanks

you can purchase it at most larger hardware stores, home depot, canadian tire, if you are in canada, you might be able to get it at wal-mart, and Iam sure you can get it at any marine supply store although you might pay a tad more and yes it is made by 3M

w2much · #10 September 9th, 2006, 12:28 AM

Thanks. Is it an adhesive or is it a caulk. ? Does it dry hard or plyable?

strizzy · #11 September 9th, 2006, 11:35 AM

+1 for patch with solid rivits and 5200. Use a solvent to clean up the extra 5200.

BF · #12 September 11th, 2006, 06:55 PM

don't try fiberglass... I bought an aluminum boat that had been "fixed" that way. Eventually it separates and leaks. When I bought my boat, I immediately wire wheeled all that fiberglass off and had patches welded where needed.

Rivets would work too if welding's a no-go.

5200 stays a bit spongy/flexible after it sets up. You might want to make sure you get the "quick set" 5200... it cures in a day... the regular stuff can take a week or longer.

Mark42 · #13 September 11th, 2006, 07:59 PM

Go with an aluminum patch. Use aluminum rivits or screws. Avoid stainless or other metal screws due to the interaction of different metals.

Use a sealant like 3m 5200 or Boatlife.

Do not use fiberglass to patch aluminum. It just doesn't hold up well.

Bond-o · #14 September 11th, 2006, 09:18 PM

I Agree a Patch is the way to Go,..................
Use a thickness as Near to the original Hull material as Possible,..... That'll help with the Stresses.....

I use something called "Closed-End Pop Rivits".........
There's No hole in the end,... SolidAluminum,....Google them Up....

I also agree with the 5200,......
Except I believe it's made by DuPont,+ No NAPA Doesn't carry it.......

Good Luck........

Mark42 · #15 September 13th, 2006, 09:23 AM

Another option is to use those aluminum brazing rods that melt at propane torch temps to attach the patch. I have never used them, but have heard good things from people who have. Might be something you want to look into.
http://www.aluminumrepair.com/more_info.asp

Tacklewasher · #16 September 25th, 2006, 07:16 PM

Nice thread to find.

I have a "soft spot" right under where my i/o motor was. I don't see any holes (but the boat does take on water and this might be the source) but I do want to fix it right.

So, is the patch put on the outside of the hull? Or can I patch the inside? I am replacing the entire floor over the winter so it will be easier to do it from inside, but I kinda like the idea of patching the outside.

Assume I do the outside. I figure clean it up, cut the patch (oversized as much as possible). Mock it in place and drill some holes. Then coat with the 5200, put the patch on and smooth out the edges. Attach with rivets and coat with the 5200 again to give a smooth finish.

Then gluvit the inside (after fixing any other rivets that may be troublesome).

Then put a new floor in.

tashasdaddy · #17 September 26th, 2006, 08:33 AM

personally i would not do the 2nd coat of 5200 outside. i would clean up any 5200 ooze around the patch and use gulvit for that.

BF · #18 September 26th, 2006, 11:23 AM

ditto on not trying to "spackle" 5200... it's more like a thick caulk that is very sticky and I don't think it would spread well. I'd wash the area with brake cleaner (acetone) first.

I don't really see how you can have a "soft spot" in an aluminum hull (?) It could easily be a couple leaky rivets. While you have the floor out, put water in the boat (with plug in) so the bilge area fills up... then look under and see what drips. Mark leaks with a felt pen and tighten those rivets up. If they won't tighten, you could replace with ss screws with bolts with a glob of 5200 on them. The time to figure it out is when the floor is out so that you can buck the back side of the rivets.

good luck.

Tacklewasher · #19 September 26th, 2006, 10:46 PM

Thanks.

Taking it to the local boat place to show him my problem. He's got a couple ideas but wants to see it first. I trust this guy as he does inspections and really seems to know his stuff (plus he is letting me test some props).

w2much · #20 September 30th, 2006, 03:25 PM

So I cut some aluminum patches, tons of 5200 and used stainless screws to attach them. All while on my back. I was quite a sight with the 5200 dripping and of course getting on my chest and back. I checked out the repair yesterday. I am confident that this method will do the trick. That 5200 has beautiful working and finish quality. Gonna fill her with water to check for more leaks. Thanks for all the help. Will post some pics when I get a chance.Project boat is geting there thanks to all of you. 18" Sea Nymph w/ 100 Mariner restore.

tashasdaddy · #21 September 30th, 2006, 05:21 PM

give the 5200 time to cure, before you put water to it. 3 -4 days.

w2much · #22 October 1st, 2006, 12:51 PM

It's not going into the water until next year probably. Yesterday I pressure washed the interior of the hull and removed more foam. This morning I inspected the condition of the aluminum. It was quite dissapointing. There is some serious aluminum rot .Places where the rot is probably half or more the thickness of the hull. A few others ready to go through the hull. I plan to do a light acid wash to remove some more of the rot in order to properly prepare the surfaces and apply a few more patches. I am curious if this is all electrolysis or if it is also the result of never having been washed down properly and salt eating the aluminum where it is trapped under the foam. I have a Gregor also,in good shape, and was wondering if the same thing is happening under its foam. I am starting to doubt the integrity of the hull.