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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 -----
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
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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