Aluminum water and fuel tanks - corrosion

[Captain Larry-DH]

I was talking with the owner of a 1998 boat that has aluminum water and fuel tanks. He said his boat had developed a pinhole leak in a fuel tank. He said he removed the tank and had it spot welded, then he completely glassed over the tank with fiberglass.
I'm assuming the leaks he found are the tip of an iceberg, and more corrosion is at work. Sounds like a practical solution, but longer term, is that a good solution?

 

[Don S/V ILLusion]

He fixed half a problem. Some might call that a half-assed solution. No more leak but the internal corrosion persists.

 

[dlochner]

No.

I'm assuming the fuel tank is for diesel. One of the causes of corrosion in fuel tanks is microbiological induced corrosion. Diesel fuel is not sterile and there are micro organisms that live in the fuel and feed off the fuel and sulfur in the fuel. They live in colonies at the interface of any water in the tank and the fuel. These critters produce by products that are acidic and the by products get trapped between the fuel and the tank. The tank corrodes and develops pinholes.

The other cause is moisture trapped against the tank on the outside from condensation which then corrodes the metal.

This is why it is important to use a biocide in the tank and to keep water out of the tank.

 

[Rick D]

I had an aluminum water tank once that I sealed. It leaked again. I fiberglassed it. That lasted about a year until the bond failed. I then had a heavier aluminum tank make. It made three years. I gave up and put two plastic tanks in. Same thing with two aluminum holding tanks.

 

[Ralph Johnstone]

He fixed half a problem. Some might call that a half-assed solution.

Actually, I believe it's referred to as a half-glassed solution .

 

[rgranger]

Actually, I believe it's referred to as a half-glassed solution .

Nice!

 

[dlochner]

I had an aluminum water tank once that I sealed. It leaked again. I fiberglassed it. That lasted about a year until the bond failed. I then had a heavier aluminum tank make. It made three years. I gave up and put two plastic tanks in. Same thing with two aluminum holding tanks.

The chlorine in the water plays havoc with aluminum. Didn't we learn in HS Bio class that urine is acidic? What were they thinking at Hunter when they put in aluminum holding tanks?

 

[RoyS]

Aluminum tanks, even custom built, are not that expensive. Patching a leaking tank is not a good solution. Try Ezell Industries in Florida for a new aluminum tank. Nice people there.

 

[smokey73]

For waste and water tanks I found a plastic tank fabricator in North Carolina - Blue Grey Plastic Fabricator - bluegreyplasticfab.com for those in the southeast and south central part of the country. In the far north (Maine) there is Triple-M. I have no business relationship with either but just a happy customer of a perfect fit custom waste tank that was made for me. Peggy also recommends Ronco who makes a wide variety of tank shapes that you may find fit your need.

For the waste tank I wanted a custom fitted tank so I didn't have to give up some volume by using a tank "almost as big." I gave them the drawing and they made a tank that fit perfectly and even had the tabs necessary for secure installation below the cabin sole.

for Ezell in Florida who made an Aluminum fuel tank for me from the original drawing with thicker walls, fittings for a fuel polishing system and two access holes in the top. Very pleased with their work although I might have gone plastic if I had more knowledge of the chemistry of aluminum corrosion at the time.

 

[David in Sandusky]

Our aluminum water and diesel tanks are leak free after 43 seasons on the Great Lakes, mostly Lake Erie. We use a biocide in the diesel tank.

I we ever need to replace one, we will buy plastic.