Steve, I'd do the test for a min of 6mo. I've hear of others doing similar tests

and only seeing effects after several months.

 

Fwiw

Jarrett [I've since never been able to find the email/site which talked about the test.. wish I'd kept it!]

 

> 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.
>
> Best Regards,
>
> Steve Thomas
>
>
>
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