That is kind of a slippery slope. The issue that that the metal has reacted to the salt and basically has eroded (think rusted but aluminum doesn't "rust") until it leaks. But the bigger problem is that a lot more of the metal is now very thin and almost no way to weld it.

I was looking at buying an alum boat, but noticed the little "piles" of white powder along the bunks. Called my mechanic buddy who has been in the business since the mid '70s and he said to run away. No way to economically fix it. You are basically just pushing/chasing the thin metal/holes all over the bottom of the boat.

 

JB weld will fill the holes and will not corrode. I've used it to repair aluminum gas tank and it lasted many years.

 

was your aluminum gas tank bouncing across baychop at 30 to 40mph fleses like crazy?/

 

Sorry, I meant flexing ,like crazy. Alum bottoms really flex as you cross bay chop.

 

Yes , put some jb weld in the holes and away you go! ImE

 

It is indeed possible that flexing will crack the epoxy in JB Weld, but I still think it is your best shot. That is unless you want to put some serious effort into sourcing two part urethane adhesive. Locktite makes a number of industrial adhesives that will flex without losing grip. If you go that route, make sure the surface is absolutely clean and follow manufacturer's instructions to the letter. I've used these adhesives for attaching tungsten carbide in place of silver solder on production equipment with great success. It isn't cheap and it won't store more than six months.

 

Don't put anything on it until you treat it and stop the corrosion and electrolysis. Bare aluminum will react with a lot of things. If you cover it, the corrosion will continue under the cover. This happens in the airline industry and with the marine industry. You will need to get your boat off of the trailer, up on jacks, then use the acid cleaner first on all of the spots, wash off, then use Alodine, the converter, and leave it on until the metal turns yellow (not too long or it turns orange or brown), then you can paint with a two part epoxy paint used to paint aluminum boats. You could also paint with clear coat Polyurethane just to cover it and protect your conversion. Yes, the metal is thinner, but after treating and painting you should be ok. Since the aluminum is converted now you could paint then apply the filler and repaint, but don't know if all that would adhere properly. Note; you have to paint over the converted yellow aluminum to protect it or it will scratch off on mud or oysters or sand and start the corrosion all over. I had it on my Boatright from carpet and replaced the carpet with plastic bunks. I got my chemicals from Crest Chemicals off of 288. One is the Acid cleaner12 (like Alumaprep) and the converter is PCC6, the same as Alodine. Their number is 800-622-9006. Ask to talk to Doug, the sales manager. He will tell you how to apply too. It is not hard to do but it is acid so wear goggles and gloves and long sleeves. You have to do it right. This was told to me by my aluminum welder who repairs this stuff all the time. If push comes to shove and you get a spot that is too thin he said he can patch it but it is not cheap. Gotta stop the electrolysis and corrosion first though still. You can PM me if needed.

 

Here is a Empire boat we fixed it was pretty bad had some holes all the way though.

 

Here is a Empire boat we fixed it was pretty bad had some holes all the way though.
View attachment 1839121
View attachment 1839129
View attachment 1839137

That's basically how mine was Repaired a couple yrs ago..Been good..

 

Fowlwaters, looks good. what thickness plate and any filling of the holes prior. What are the two grinded areas for in the middle of the plate. Did you have to treat the new plate or just paint over it and what paint did you use? Just wondering.

 

No paint clean the infected area and seal welded patches of them so no need to fill in the holes the areas in the center of the new plate you see are where we drilled holes in new plate to weld to the bottom of the boat so the patch is seal welded around and welded in the middle.

 

X2 on the epoxy. Thousands of in-water yachts that have suffered blistering have been treated very successfully with multiple coats of 2-part epoxy (West System, etc). I'm assuming the problem is on the outside. I imagine you'd have to take it down to bare metal. Epoxy is more flexible than polyester resin, and more adhesive too, so it might stick well and hold up to the pounding.

If it were me, I would probably try it. I've used epoxy many times, and I'm a believer. It goes on easy with a roller. Basically turns into an impermeable plastic barrier.

One downside......you have to either paint it or store the boat out of the sun. Epoxy is not UV tolerant.

 

Epoxy or JB weld if it does not hold up will only drive up your repair bill later have to get it all off before welding can be done. If the boat is in good shape other then the pitting then fix it right and be done with and never worry with it again.

 

Smart to weld in the middle too! I agree, no epoxy or JB weld. I did convert the bare aluminum with Alodine. May still patch weld it.

 

Are your bunk boards treated lumber? I've read that the chemicals in treated lumber will react with aluminum. You might want to change them to untreated lumber or put plastic sliders on top of the carpet.

For the past 9 years our bunks have been untreated yellow pine covered with cheap green outdoor carpet. We have had no corrosion along the bunk areas.

We had some pitting on the bottom from galvanic corrosion. Three years ago I painted it with Duralux marine paint. Looked at it this summer and still looks good, no sign of further corrosion. I had also added a nice big anode to the transom.

 

Are your bunk boards treated lumber? I've read that the chemicals in treated lumber will react with aluminum. You might want to change them to untreated lumber or put plastic sliders on top of the carpet.

For the past 9 years our bunks have been untreated yellow pine covered with cheap green outdoor carpet. We have had no corrosion along the bunk areas.

We had some pitting on the bottom from galvanic corrosion. Three years ago I painted it with Duralux marine paint. Looked at it this summer and still looks good, no sign of further corrosion. I had also added a nice big anode to the transom.

This ^^^^ is the right answer.
Guys, NO TREATED LUMBER in, on or under your alloy boat.

 

Its from eletronics grounded to the hull and saltwater being trapped on the bunks. Every aluminum boat should have a Perko switch to turn off batteries and everything should be grounded back to the battery.

 

I talked with Fowlwaters the other day. As soon as I get a day off or some daylight I am going to jack the boat up to see just how bad it is. I am pretty sure it will end up with him getting fixed no mater how bad it is. I do not want it to worsen and I am going to do it right the first time. It did have carpeted bunks until recently. While I was rebuilding my trailer I put pressure treated wood down. I ripped 2X6's so that plastic rain gutters fit over them. You have to rip the gutter in half too but they work really well. So there is a barrier between the wood and boat. It was when I was under the boat bolting the new guild rails up that I noticed the pitting. It isn't leaking and to me it seems minimal but we will find out how bad it is soon.