Has anyone here used an epoxy/whatever product to repair pitted aluminum diesel tanks

[Renegde_Sailor]

Originally Posted by Oeanda

Well as mentioned above, removing the tanks would stop the fun for a long long time. It’s very hard to think about. But if it has to be done, we would end up gutting a very large amount of the boat, and replacing all tanks, and probably the engine, and probably plenty more besides. Shudder…

That is always the razors edge we balance on as a boat owner, when to stop spending money on her?

[s/v Jedi]

If you are testing, make sure to test it with the original formula JB Weld (not the 5-minute cure etc.). It has worked very well for me on aluminum (it has aluminum filler iirc)

[geoleo]

Originally Posted by Renegde_Sailor

Once aluminum has started to exfoliate like that, it is near impossible to stop.

You can clean the surface, prep it the best you can, and put epoxy over it, and it will still come apart.

The best option you have is to pull the tank and get it to a welder, but an even better option would be to build the same tank out of stainless, (or if you wanted to get nuts monel) or get a plastics guy to make new tanks out of HDPE.



Personally, I like HDPE (and I am saying this as a professional welder) because it is never going to corrode. If you can find someone who knows how to work it, you get a first rate tank with no future issues.

How could DH Lawrence possibly know what a lil bird is thinking??

[Seighlor]

My 1988 boat has two large aluminum fuel tanks. Both tanks leaked when I purchased her, a half dozen years ago. Fortunately, the tanks were canted very slightly so that any water in the fuel flowed to the lower ends. That's where degradation in the bottom plate occurred.

I contacted West Systems Epoxy (https://www.westsystem.com/) for their thoughts on implementing a repair. Sorry, I no longer recall the number of the product recommended at that time, but you can make the contact for an update.

Making the repairs was not difficult... just a good cleanup; no etching. Then an application of the epoxy and glass as recommended by the good folks at West Systems. The results, five years later, have been great. Absolutely leak free.

[lrclough]

I used West System G Flex Epoxy to repair leaking 30 year old 55 gallon aluminum water tanks on my sailboat in the Caribbean. Three years later everything is fine.

G Flex is a variation on their standard epoxy which has greater adhesion and resilience but somewhat less ultimate strength.

I carefully followed the instructions included in the package, namely sanding with wet and dry sandpaper, then cleaning with acetone. I thickened the epoxy with West 406 Colloidal Silica Filler to help control viscosity on the vertical sides with pin holes.

Do not wire brush with a steel brush.

A call to West System would likely be helpful if you need more info.

[col50]

Originally Posted by hpeer

Aircraft use a 2 part epoxy to join aluminum plates to make fuel tanks.

https://skygeek.com/flamemaster/?gcl...AaAs3bEALw_wcB

Boatlife also sells it at an inflated price.

You MUST have all diesel off the metal but once applied it WILL stick. Damn messy stuff, worse than 5200.

This is not an Epoxy. It is a 2 part Polysulfide Rubber compound similar to what aircraft manufacturers use to seal aluminum wings, to make them into fuel tanks.

[MVDarlin]

I had my black iron tanks cleaned a few years ago. They made an access hole in the top and sent a man inside. He cut out the baffels removed 5 gallons of goo from each side, re attached the baffels and polished the fuel. All good.

I once used an aircraft tank sealer product to repair a leak in my motorcycle tank. Expensive stuff.

[Shaneesprit]

I repaired an Aluminium oil sump once with “JB Cold weld” epoxy and did this while it was leaking without taking the oil out!
Jack cracked the sump while supporting the engine - Sump / Jack was fine supporting the engine until the car tyre went down.
Also repaired a car fuel tank in the same way although believe that was petrol from memory so probably steel tank.
Still it’s a bodge job and you will never be happy unless you do it properly.

[Alex A]

Oeanda,

It has been done many times. If you search the YouTube channel -Vet Tails’ Sailing Chuffed- they have a pretty good video showing you how you can repair the tanks. It is based on the West System recommendations.

Here is a link:

https://youtu.be/QRYi1Olv9nE

I have integral tanks which had some corrosion and this is partly how we sealed them.

[Cheechako]

IME aluminum is the worst for tanks. Now that you have them open, fit plastic tanks inside the aluminum shell and never look back!

[NSboatman]

Originally Posted by massnspace

I did this (successfully) on a boat I once owned.



The secret: apply epoxy then wire brush it into the metal while it is still wet. The layer of epoxy will prevent air from reaching the newly brushed surface. Then I added a layer of fabric and a final flow coat of epoxy.



I had to buy and throw away several wire brushes. But they were cheap.

This works. Wet sanding/brushing epoxy on aluminum has been the only way I’ve gotten good results of this type. Ymmv…

[nofacey]

Just deal with the bad pit, degrease, abraid well, Use JB weld - fixed multiple items over the years, aluminum, diesel included, always held.

[col50]

Gee, I wonder why Boeing doesn't use epoxy to seal fuel tanks on their airplanes.
They use polysulfide rubber, and have been doing so since world war 2.

[GrowleyMonster]

So the controversy, if there is one, is the quality of the bond with aluminum. What if the bond was made superfluous? Coating the entire inner surface of the tank with epoxy? This might also work for many years to prevent future leaks. Of course that would be expensive for a large tank, but everything is expensive when you combine the words "large" and "marine" in one sentence, anyway. Anyway with essentially an inner shell of epoxy to contain the fuel, and the original tank to provide mechanical support and limit flexing, you might have a winner, and for like a 20 gallon or smaller tank, the cost shouldn't be prohibitive. The down side is you could no longer weld or braze anything to the tank. Just an idea, not a suggestion. Anybody have any input on that?

[jcapo]

I addition to the info in this thread, there are several threads on the trawler forum about repairing fuel tanks. Sorry I don't have links but the search function will reveal them.


I'm replacing one steel tank with aluminum and patching the other steel fuel tank. I will use some sort of epoxy on the exterior and Flamemaster internally.


Aircraft Spruce has products similar to Flamemaster including one or two from Boeing. Boeing knows a thing or two about aluminum fuel tanks.