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I think the reality is that we need to make every effort to avoid auto fuels with ethanol in our fiberglass tanks. Best I can tell is that the Jeffco is the most resistant best bet for coating.

Al G

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Schertz
Sent: Monday, January 22, 2007 5:16 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: alcohol in fuel

Charlie Smith, who used to be on the list but isn't any more is an industrial chemist. He is building the same plane as I am, and we use the Aeropoxy system. As a test, I made up some samples (1" square pieces of fiberglass) and coated them with Jeffco 9700 FCR. He made up some samples coated with Aeropoxy. He then weighed them and then soaked them in 10 (or 15?)% alcohol in gasoline. The Jeffco samples did swell some and gain some weight, but remained intact. The Aeropoxy samples flaked off and disintegrated.

Our interpretation was that the Jeffco coating is fine, but we are still concerned about the joint where the wing skin is bonded on as the last step to closing the wing. That area is impossible to coat with the Jeffco. That bonding agent is a Hysol material that we have not tested with the alcohol.

Bill Schertz
KIS Cruiser # 4045

----- Original Message -----

From: James Maher

To: Rotary motors in aircraft

Sent: Monday, January 22, 2007 9:33 AM

Subject: [FlyRotary] Re: alcohol in fuel

I used both the Aeropoxy and West Systems in the construction of my integral fuel tank.

I can now confirm that the tank has been severely deteriorated by the use of auto fuel, mostly in the last year or two since ethanol has been added.

Jim

Dyke Delta N11XD

Dale Rogers <dale.r@cox.net> wrote:
To put a bit of perspective on this, one will be hard pressed to find a
laminating epoxy that is in the 100:25 range, such as Al W wrote.

E-Z Poxy 100:45 by weight

MGS 285/287 (and 335) 100:45 by weight

Pro-Set 100:30 by weight

AEROPOXY is 100:27 by weight

ACSpruce's data on the West System 105/205 spec was "5:1"
which suggests it is a volume measurement, but it doesn't have
the Rutan Blessing, last I knew.

IIRC, Perry Mick used MGS 335 and runs auto fuel in his EZ.

Al Gietzen wrote:

Al W wrote:

After flying for six years, finally removed and disassembled my glass and

foam header tank. During those six years I periodically used ethanol fuel

and whatever. Always used auto fuel. No evidence of degradation of any

component....soft aluminum, foam, epoxy. All looks perfect.

That’s good news.

Just a reminder, all epoxy that is fuel exposed must be high ratio type.

Like 4 to 1. 50/50 ratio epoxies can NOT handle “fuel” over time.

That’s bad news. Should I conclude from this that EZ-poxy (44-56 by weight) will NOT handle fuel with ethanol? I assume when you say “fuel” you mean fuel with ethanol, since experience has shown that EZ-poxy has handled auto fuel for periods of 15 years in some EZs.

Al G
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