Ethanol effects on copper and brass

Here is a time-lapse photography series to study effects ethanol can have on copper and brass in gasoline applications. At start are two photographs showing copper and brass samples immersed in California pump fuel 87 octane. This pump fuel has about 10% ethanol year round. Ethanol is not required in California but oxygenates (such as ethanol) are required for smog reduction reasons.

Photo on left is sample with a 1 cm hole open to atmosphere at top of bottle. Photo on right is sample sealed from atmosphere.

This photo is the same sample set taken a month later. The fuel level on the left is substantially lower not from evaporation but because I poured some of that fuel into a bottle and sealed it without any copper or brass samples.

And here is a sample of pure ethanol with copper and brass samples, about one month in a sealed bottle.

What tests along these lines would anyone like? It seems pretty easy to put a bottle on the shelf and look later.

The effect of ethanol is due to many parts, if the copper was heated then cooled, moisture in the air, expansion and all that.
Ethanol in a closed loop such as a fuel injected car in dry California, will have little effect until it is exposed to air like a carb open system then moisture and all the rest.
Unless I missed something.
Run both in a motor or lawn mower, now that would be interesting.
Ethanol is a filler ….a GARBAGE filler.
In the northeast change of temps and moisture is the downfall when it sits.
I had my 56 tbird running fine, then came a couple of parents in hospitals and worse .
When I went back to the car 8 months later the diaphrams and tank were junk.
It was like rocks in the tank.

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Some soldered joints, both leaded solder, and lead free.
(I think I see more sunk floats now than pre-ethanol - but originals would be leaded solder.)

Also, another test which exposes the metals to air and Ethanol alternately. (Jets and needles aren’t always immersed, nor are they only exposed to fumes.)

There is a reason they don’t use it in aircraft.

Aluminum is affected by alcohol.

Brass…not realy a surprise.

Most cars have aluminum pistons. This suggests aluminum and ethanol are not problematic together in the combustion chamber since ethanol has been used for decades in gasoline.

Ethanol is used in some aviation fuel applications, but not widely. Ethanol has lower energy density than petroleum aviation fuels and thus reduces range for a given fuel volume. Ethanol presents phase separation, vapor lock, and icing issues for airplanes due to altitude and cooling issues. Are there any issues of ethanol blocked for aviation usage due to chemical interactions with aluminum?

Copper is used in stills for alcohol production. Copper is directly contacted by the ethanol when making drinking alcohol. Stills have both copper and solder joints. Apparently stills must be cleaned on insides after several years due to sulfur compound buildup from products associated with the yeast production. Not having found copper corrosion problems from chemical contact with ethanol in stills, does anyone know of copper corrosion in stills due to ethanol contact?

Following up on the sulfur compound production on copper, there is a study of copper and steel corrosion rates related to fuel storage tanks with the metals in the presence of acid-producing bacteria. These studies found copper and steel corrosion rates of about one human hair thickness per year for metals in the headspace over a yeast extract including 5% ethanol by volume. This corrosion was associated with acetic acid produced by the microbes. See “Corrosion of copper and steel alloys in a simulated underground storage-tank sump environment containing acid-producing bacteria” by J. W. Sowards and E. Mansfield in Corrosion Science 2014, volume 87, pages 460-471.

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And to follow up on the suggestions above, I will put some aluminum in ethanol and also in the E10 fuel bottles. As well, I will pull out some old carb floats and submerge in ethanol and maybe also E10.

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Here is a two month photo of the different samples.

Following up on the suggestions for testing above, aluminum foil is in the headspace of all the bottles now. Not showing the aluminum exposed to the fuel fumes, by eye the aluminum appears unchanged thus far.

Leftmost sample is E10 with open hole to atmosphere at cap (copper and brass samples visible). Left middle sample is E10 sealed cap (copper, brass, and aluminum foil visible). Right middle is E10 (no copper or brass, aluminum visible). Righmost sample is pure ethanol with copper, brass, and aluminum visible.

Maybe next month I will open all the lids to increase the atmospheric exposure.

My guess presently is that aluminum in these tests will not show problems with E10 or with the pure ethanol. Aluminum is widely used for fuel tanks for ground vehicles and airplanes.

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Ethanol not used in ANY civilian aircraft in the US that I know.

The fact that the ethanol will bond to water presents another problem. Once its bonded it can’t be removed from your tanks.

Doesn’t do much for rubber diaphragms and o-rings either.

Its easier to just remove the ethanol rather than run with it.

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The Texas epa just wrapped up a long study with boats and aluminum tanks with ethanol
There concern was after eating through the tank gas would go in the water
Look it up they have bottles of metal shavings when they drain the tanks
Two thoughts
1 Anyone that still does not believe , oh well
2. This topic will be dead soon since we are going all electric real soon
This week come the pebble auctions
Get ready for huge drop offs as the aged man is bailing out of the old car hobby
I pace is coming
Plug me in and out!