Aluminum pitting

SuperPanga · 06-30-2009, 06:28 PM

Friend of mine is looking at an aluminum boat with low hrs, about 5 years old. Upon inspection he found deep pitting due to several years moored in saltwater without any zinc. What can be done? Beyond repair?

fishkisser · 06-30-2009, 06:55 PM

Pull the motor and put it in another hull ...
Once the metal has been removed by pitting there is no way to put it back ...

honker1 · 07-02-2009, 07:46 PM

Found deep pitting in my Starcraft when I replaced the floor. Used a wire brush on my grinder and cleaned the spots so I could see my shining teeth. Wiped it clean with acetone and filled the pitts with Marine Tex gray. Sand smooth and paint. Haven't fallen through the bottom of the boat yet and it has been 3 years. Still worry about the pits that I may not have found.
I am just telling you what I did, but my advise would be to not purchase the boat.

Pelagic Captain · 07-04-2009, 11:20 AM

I bought a new Starcraft in 1977...after several years the floor vinyl needed replacement so I removed the floor and found pitting throughout the hull. I took it to an aluminum fabricator and he said get rid of the boat. I coated the interior of the hull with an epoxy type paint and ran it for several more years..the boat was sold at 17 years and I heard of no issues with the hull. This boat was moored in fresh water a couple of summers...I never could figure out what caused the pitting. Starcraft at the time had a 5 year hull warranty and offered no explanation to the issue and no help as to a fix. I have an aluminum sled now and at times worry about pitting under the floor.

Lead Bouncer · 07-05-2009, 07:24 PM

new panel or maybe a lamination

No Fish · 07-08-2009, 10:28 PM

I saw an aluminum work boat at Port Angeles that was left in salt water. It had barnacles and pitting. Buy a diferent boat. I would never leave my aluminum boat in salt water for an extended time not without it being painted with antifoul paint.
Now for my aluminum pitting story. A few years ago after a few years of owning my current boat, I decided to look under my deck plates. I found 1 inch spots about every 8 inches and up about a foot from the keel. in the center of each spot was a 1/8 inch pit. I talked to everybody I could find and they all were puzzled. I soon realized that most of these dealers and owners had never seen under these deck plates. These boat builders ruled out electrolisis. Finally I called Alumaweld in eagle point and asked the lady on the phone to let me talk to their best aluminum guy. He came off the floor and I discribed my situation. First thing he said was that they used to have the same problem and discribed it to a tee.
I asked him what it was and he told me it was contamination. Jetcraft had used a green tinted marine plywood for deck plates. The top has vinyl but the bottom was bare. The water splashing up from the bilge was washing the green copper preservative out of the plywood and putting it in the bilge. The copper ate the pits in the aluminum. I asked him what they did and he said they had the plywood factory wrap the plywood from then on. He told me to cover the plywood bottom with visqueen and that all the damage was probably already done. I sanded and gloveted the inside and covered the plywood. I am going to PM tally, grain of salt and taf to see if they will call me and discuss their corrosion problems. This is my corrosion story and I am sticking to it.

ET · 07-10-2009, 09:30 AM

I know many fishermen on ifish love their aluminum boats, but aluminum corrosion is the single reason I stick with fiberglass.

Yes, I know the advantages of aluminum, but when the disadvantage leads to needing to throw the hull away...... I'll stick with fiberglass....especially for saltwater, recreational use.....

I just don't like the feeling of sitting in a boat that may be corroding around me.

arkansasbasser · 07-13-2009, 10:12 PM

Quote:

Originally Posted by ET

I just don't like the feeling of sitting in a boat that may be corroding around me.

Where's your sense of adventure? That's living on the edge man. Keeps your senses sharp.

Lady Ellen · 07-21-2009, 03:27 PM

Much to my dismay, I found aluminum pitting in a Sylvan 23 ft boat I recently purchased. The boat is 12 years old and has four small holes in the transon and who knows were else. Has anyone had any experience with some of the products advertized for aluminum repair? Cabellas has a kit, the marinas sell a metal apoxy stick for aluminum and there is a material that you heat up the aluminum first and then apply an epoxy like material into the holes. Are these just stop gap patches to a bigger problem of the boat melting around you???

LADY ELLEN

Magee · 07-22-2009, 07:17 AM

Quote:

Originally Posted by Lady Ellen

Much to my dismay, I found aluminum pitting in a Sylvan 23 ft boat I recently purchased. The boat is 12 years old and has four small holes in the transon and who knows were else. Has anyone had any experience with some of the products advertized for aluminum repair? Cabellas has a kit, the marinas sell a metal apoxy stick for aluminum and there is a material that you heat up the aluminum first and then apply an epoxy like material into the holes. Are these just stop gap patches to a bigger problem of the boat melting around you???

LADY ELLEN

I had the same problem with my Smoker Craft and used Marine-Tex epoxy. After replacing my zinc anodes and patching a few pits with Marine-Tex, I haven't had any further problems. The epoxy is available at about any boating supply place.

Chesapeake · 07-24-2009, 03:17 PM

Quote:

Originally Posted by Lady Ellen

Much to my dismay, I found aluminum pitting in a Sylvan 23 ft boat I recently purchased. The boat is 12 years old and has four small holes in the transon and who knows were else. Has anyone had any experience with some of the products advertized for aluminum repair? Cabellas has a kit, the marinas sell a metal apoxy stick for aluminum and there is a material that you heat up the aluminum first and then apply an epoxy like material into the holes. Are these just stop gap patches to a bigger problem of the boat melting around you???

LADY ELLEN

The older riveted hulls often have pitting in them, and or the rivets are corroded and brittle. I think the biggest issue with these boats is gap corrosion and moisture.

Your transom is 1 1/4 (memory) plywood mounted with stainless screws and or bolts. Its held up off the bottom of the bilge a bit so it wont see much water down there, but if the splash well drain tubes leak, or someone drilled below water holes in it to mount transducers and such. It will get wet and may remain wet. This is turn will cause the transom aluminum to corrode rapidly from the inside out. If you remove the transom plywood you will likely find alot of white powder residue left over from the corrosion.

At 12 years of age you probably want to look at replacing the transom wood. Depends on how it was cared for.

Another thing that will kill these boats is storing them with water in the bilge for extended periods. This seems to damage the rivets more than the skin of the hull.