I have had auto gas in my Long Ez
tanks, made from EZ poxy, for over 4 years. I never had any problem with
my tanks until Florida went to the 10% ethanol gas last summer. My
problem has not been the tanks but the clear sight gauges I added several years
ago. The clear outer plastic did turn yellow over time. However, once I
started using the ethanol base fuel the white plastic backing to the clear
sight gauge just melted within a month or two. These gauges were an after
market replacement for the original Rutan design. I have had EZ poxy
strips in a jar of ethanol gas for over nine months now with no sign of
problems.
Sent: Thursday,
July 30, 2009 9:24 PM
Subject: [FlyRotary]
Re: Using Ethanol-laced Gasoline
Steve;
What’s
the chance you could add some samples of EZpoxy layups? I’d be
happy to send some.
And
I agree with Jarrett; plan on 6 months to a year. You probably
don’t need to check them more than every couple of weeks, or a month.
Al G
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Steve Thomas
Sent: Thursday, July 30, 2009
11:57 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Using
Ethanol-laced Gasoline
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.
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.
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