Aluminum Vs Ethanol

[chimpvalet]

Hey people,

New fuel tanks on the chore list for a couple of cars, pondering what material best from which to fabricate. Aftermarket tanks in AL are found in the UK for these cars, not cheap and freight costs are somewhat high right now so considering to have made locally. Our last remaining E0 fuel, Chevron 94 octane, has just gone E5, likely by government decree. The push away from petroleum in fuels seems unstoppable, though at least quite gradual looking ahead. Would stainless be a good hedge against ever greater ethanol content or would aluminum be alright?

Thanks
Steve

[rgalajda]

Aluminum has been used for years in carburetors ( Carter ) . The fuel wasn't the source for deterioration as much as the water that ended up in the fuel. That water caused a lot of oxidation/ pitting in the fuel bowls. That water came from the fuel tank, caused by condensation from the air in the tank of less than full fuel tanks. Fuel ( gasoline ) floats on water. Start the engine after storage and you suck up the water.

Years ago when I was still a snowmobiler, one morning I opened the fuel tank and shined a flash light in the tank to see a frost covered interior of the tank. Ever since then I have always filled the tank of my car ( snowmobile and lawnmower ) before storage to disperse the humid air .

We flush the brake fluid to replace with new . Brake fluid is hygroscopic ( absorbs water ).

Ethanol and water bond together. I do not believe ethanol is particularly corrosive to aluminum, but I'm no chemist.

[chimpvalet]

Thanks @rgalajda, that brings focus to the relevance of water in this, as I already well understand. Aluminum in the appropriate alloy is not particularly susceptible to deterioration by exposure to water, as countless boat hulls demonstrate. When substantial ethanol content exists perhaps there is wisdom in drawing ambient air via a dessicant for replacing fuel drawn from the tank.

[Kevin Johnson]

https://www.researchgate.net/profile/Be ... 351-10.pdf

https://en.wikipedia.org/wiki/Glovebox

[chimpvalet]

So I guess no one sees much reason for concern on use of AL for fuel tanks? Re the links provided it seems there are both inbound water vapour and outbound HC fumes to contend with in a dryer device.

[Walter R. Malik]

I believe that "Alcor" would be a better choice than plain aluminum for a fuel tank.

[In-Tech]

Hiya,
Stainless is the best but it is heavy. A lot of times, I will use aluminum to cut the weight and have it hard coat anodized. The hard coat is a darker grey, many times it is black anodized after.

[jsgarage]

Anodizing (not hard-anodizing) might solve your problem. As for the aluminum to use, it will likely be the do-everything 6061. Many desirable aluminum alloys are not weldable so they won't make good tanks.