Patching aluminum corrosion

[UNCC Grad]

I have some corrosion that has formed on the bottom of my aluminum hulled 16' boat. It has began pitting the aluminum enough to where it needs to be filled. Oddly enough, these areas are right where the rear bunks support the hull. I use it in mainly fresh water, but I sometimes use it in brackish water for hunting and fishing. Nothing is grounded to the hull, but there has been in the past which is where I suppose the corrosion started.

Can anyone tell me what to use to fill these voids? JB Weld, epoxy putty, etc? I plan on painting the areas with epoxy paint when completed with the filling. Is this the right plan?

 

[UNCC Grad]

Re: Patching aluminum corrosion

Surely someone has a suggestion? I picked up some Permatex Multi-Metal epoxy thinking it would bond better to the aluminum.

 

[getinmerry]

Re: Patching aluminum corrosion

I don't know if this is right or wrong, but I had the same problem and needed to fix it quickly. Here's the way I did it.

1. Coarse wire brush on a drill. Clean the area until it shines. Clean with acetone or brake cleaner and let dry.

2. Coat with JB Weld and let dry for 48 hours.

I did this on a pitted area on one of my boats that was just starting to leak. That was 4 years ago. So far it's holding up perfectly. My boat is stored outside and takes a lot of abuse (dragging across rocks to beach it) and there isn't even the slightest sign that the JB Weld is failing. I love that stuff!

Chuck

 

[45Auto]

Re: Patching aluminum corrosion

I've had a lot of success on corroded outdrive housings by following these steps:

- sand or bead blasting to remove all the corrosion
- applying an aluminum conversion coating
- filling pits with an epoxy putty
- paint with epoxy primer
- paint with final color

I like the PPG Alodine 1201 for a conversion coating. I usually just use this Mercury procedure:

http://northamerica.mercurymarine.c.../mercruiserfaqs/technicalinformation.php#1135

 

[HONKER1]

Re: Patching aluminum corrosion

I restored my 18' aluminum Starcraft. In the transom area I had pits all over. Some had eaten completely through the aluminum. I cleaned the area with a grinder and wire brush until it was shiny and then coated the aluminum with a thin coat of Marine-Tex The wire brush left enough scatches for the Marine-Tex to bond with the aluminum. It had been 2 years now, and still bonding and no leaks.
If you have just 1 small spot, JB Weld is a good product. Used it on small spots with good success.