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| I am in the process of testing the effect of ethanol-laced gasoline on my fiberglass tanks. My airplane is made from vinyl-ester resin, not the epoxy resins used by many other aircraft. Vinyl-ester is touted to be immune to the effects that ethanol has on other products. Someone on the Glasair list had some problems with ethanol, so I decided to run some tests. What follows is the analysis I posted on the Glasair list. It has implications for all of us rotary guys as well. When I speak of Jose Cuervo, I started a test of very high concentrations of ethanol using Jose Cuervo as my medium. It is 40% alcohol.
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I thought that I would update everyone on the Ethanol
"research" that I have been doing. I now have three test
jars set up. One jar has the infamous Jose Cuervo in it.
The second jar has pure 91 octane gasoline with 5.7%
ehtanol and the third jar has 91 octane gasohol (same as
above) but laced with water.
The Jose Cuervo jar has two samples in it; one is a sample
of precure that is something I made up several years ago,
and the other one is from the original kit. Both samples
have been in the jar for a week. So far, there is no
noticeable effect on either sample.
The gasoline-only jar has three samples in it. One sample
is from the original factory lay-up. One is a brand new
layup that I did a little over a week ago that was allowed
to cure for 48 hours. The third sample is from the same
layup just completed, but was cured in an oven at 200
degrees for 3 hours. Again, no noticeable effect on any of
the three samples after one week. This test will go on for
a while longer just out of my own curiosity.
The third jar has the water in it. it also has just one
sample in it, one of the original factory layups. The water
at the bottom of the jar has turned a light brown color. It
has clearly leached the alcohol and some other products
out of the gas as the water level has grown. There is no
effect on the sample layup, either in the gas or the water
(I have it standing up in the jar so that part of the sample
is in the water and part in the gas.)
But the final coup de grace comes from a conversation I
had with a BP/Arco technical products engineer. He told
me that first, California currently has a ethanol ratio of
5.7% but will soon be changing to 10%. He also said that
the fiberglass tank problem is nearly irrelevant because,
as ethanol laced gasoline gets colder, the ethanol will
come out of solution and unless your engine is capable of
burning pure ethanol, you should avoid using any
ethanol-laced gasoline at altitude. If you were to ever
find yourself at very cold temperatures (he didn't specify
how cold), the likelihood of ethanol coming out of
solution is very high.
Now, it also possible (but not probable) that one could
obtain an exemption from the Air Resources Board to get
ethanol-free gas for experimental purposes, the
likelihood of finding someone to sell that small volume is
nil.
The engineer also told me that it is possible to leach the
ethanol out of the fuel. I do not recommend this
procedure (legal disclaimer). one can leach the ethanol by
adding water to a tank of fuel, agitating it, then cooling it
down as far as practicable to ensure that all of the water
falls out. Then, remove the water layer. If you don't cool
it down, micro-bubbles will remain in the gasoline that
will fall out over time. Any takers?
So, at least for now, it seems that the effect of ethanol on
fiberglass is somewhat moot, despite my inability to see
any effect on the samples I have in process.
Best Regards,
Steve Thomas
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