The factory supplied sight gauge tubing is polyurethane. After a couple of
years
I noted that it was getting quite hard. I searched the Tygon website and
discovered "fuel line" tubing, Tygon 4040. I changed out the tubing in our
Europa
to that during our rebuild. I later discovered that Tygon 4040 was supplied
with the Long Range tank, and the length of it installed in our main tank
had become quite hard and opaque! Back to the Tygon website. There I found
Tygon
SE 200 which is PVC with a Teflon liner. Other web searches revealed that
Teflon is the preferred material to resist gasoline.
I purchased samples of Tygon SE200, 4040, Tygothane C210A (polyurethane without
plasticizers) and Tygon 2075 (high chemical resistance) that I have been testing
for about 3 weeks so far. I filled a 6 inch length of each with auto gasoline
and sealed both ends. SE200 has lost the least amount of gasoline so far,
about 1". 4040 has lost 4" and C210A has lost 3". 2075 was empty the next
day!
I also put short pieces of each in a jar of gasoline. 4040 and C210A haven't
shown
any change yet. SE200 the PVC has shrunk leaving a portion of the Teflon
sleeve exposed at each end. 2075 has swelled up from it's original 1/4" ID to
more than 3/8" ID.
My conclusion so far, is SE200 is the best for a sight gauge or any application
where fuel will not be in contact with the outside. Tygothane C210A is probably
best where fuel will be in contact with the outside. This is based on my
experience with 4040. I'm continuing the testing to see long term effects.
All of the Tygon tubing is available from McMaster.
Hope this helps.
Jim & Heather
N241BW getting close to flying again
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