Group,

After over 11 years of building on a Glass Goose, I may be finished. Not
finished in a good way, though. I filled my wing tanks several months ago
and was delighted to fire up my Renesis. Today, a month later, I noticed the
leading edge cap separating from the wing near the wing root and leaking out
of it. With further investigation, I also discovered leaks on the bottom of
the opposite wing at the shear web. The residue of the leaks is yellow-tan
in color and sticky. My conclusion is that the alcohol in the gas has had an
adverse affect on the epoxy. I'll call the epoxy maker on Monday to get his
words. I read about the effects of alcohol on epoxy on the internet several
years ago but was assured that it wouldn't affect a tank that was Jeffcoed.
Sealing the tank is the least of my concern. What makes me think the wings
are now unreliable is that the fuel has wicked up into many areas of the
wings' integrity so, at this time, I don't think I can trust them. I offer
this as a warning to those that can use it. Do any of you have any ideas or
words that can help save this poor little airplane.

Sandy McNabb
Renesis in a Glass Goose (retired)



I am not familiar with the construction of the Glass Goose Wings. Is it a
layup over the blue foam to form the wing (ala Rutan), or is it molded wing
skins and ribs? On the KIS Cruiser, it is molded skins and ribs, and the
wing is built upside down, then the bottom is glued on to close the surface.
Although I coated the interior of the fuel bays with Jeffco, which can
supposedly take ethanol, the joints where the bottom skin is glued on could
not be coated. Therefore I have imposed a 'no alcohol' condition on my
plane, since that joint could be attacked. Also, we did some immersion tests
of coupons coated with Jeffco, and although it did not disintegrate, it did
swell some, which led me to shy away from gasahol on that basis.

I am very sorry to hear of your problems, you might talk to the Kit
manufacturer about possible repairs. If it is skins and ribs, and the foam
from the sandwich parts is fuel resistant, Maybe you can open up the skins
(hand opening) and reinforce each joint with a bid layer . If the wing is
layup over blue foam, that is not possible, as the foam would have
disintegrated from exposure to fuel.

Bill Schertz
KIS Cruiser #4045
N343BS
Phase one testing Completed

BTW Bill is a very competent chemical engineer. His advice has
helped us out greatly in the last 12 years.

I have a question for you Bill. How does one bond
neoprene/bitrile coating? I am thinking we can make our
own custom fit fuel bladders. Perhaps a common household iron
can be cannibalized for heating elements. Perhaps thin
sheets of 500 F Teflon between the heating device or bonding clamp
and the material can prevent the two from sticking
together. Perhaps just a butane torch can be used
to heat the bonding clamp. A hand held infra red
thermometer can be used to check the temperature
of the bonding clamp.

http://www.justgastanks.com/store/index.php?main_page=index&cPath=365

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McMaster Carr sells Neoprene coated nylon cloth for about $5.30
per foot. Comes in 60 inch wide sheets up  to 50 feet long in one
foot increments. Two thicknesses .022" (fine for our use) and
.040" overkill. They also have Polyurethane coated nylon but
I do not  know how well it resists fuels. $3.82 a foot.

Paul Lamar