If you want to be able to run the actual car gas the tanks should have 2 to 3 coats of Rhino 9700. It is an epoxy but has a Novolac backbone which stops the effects of alcohol on epoxy. I have been using it for many years from my days of building Lancair's and the 2 KR2's I completed. Neat thing about 9700 is it is also a structural resin. It does enter B stage very quickly even on cool days.
Richard Kaczmarek On Sat, Dec 6, 2025, 10:33 AM Joe Horton via KRnet <[email protected]> wrote: > Good Morning Folks, > I am sharing this story again as a warning to anyone with epoxy > tanks. > On the way back from the gathering in Tennessee I think in 2011, I chased > the cold front home all day with landing multiple times to wait for it to > move ahead of me. I ended up landing somewhere south of Harrisburg PA. > about 10 min after the FBO closed and they had no self serve. A local took > me to a sonoco and I got 5 gal of 93 oct. (ya know the NAS Car racing > fuel) and put in the header tank with several galllons of 100LL that was > still in the tank. I flew for another 50 miles or so and had to call it for > the night 50 miles from home. Left early the next morning and got home and > to work before 7 am. I think that I flew again on maybe Wednesday or > Thursday of the same week and noticed a bit of roughness in the engine > operation. My memory is a bit foggy on the details of why I started to > investigate but at somepoint that weekend I looked into the header tank and > the erosion of the gel coat inside the tank was so evident. There was a > line exactly where the fuel level had been when I put the 5 gal of Sunoco > in. There were glass cloth fibers exposed. I drained and cut tank open and > repaired it, but started to wonder about the epoxy that had erroded off the > inside. I tore down all the intake and aerocarb and found a coating of the > epoxy (vinyl ester) inside all the intake tubes and in the carb. I pulled > heads but it appeared that the epoxy that may have gotten to the cobustion > chamber burned with the fuel. What a mess. > This was the first time that N357CJ had seen auto fuel in the 6 or 7 > years of operations. > I did try it at an airport in South Caolina at a Corvair college with non > alcohol fuel and the engine ran so rough I drained it back out gave it to a > local and filled up with 100LL. The plane never saw any auto fuel again. > Mark L. has the plane now but to the best of my knowlege the wing tanks are > still fine and the header tank has another 14 years or so on it Total of > over 20 years now. > My current build has aluminum tanks in the wings so that should not > ever be an issue. The header tank was home built with just over 8 gal > capacity and has had fuel in it for nearly 4 years now. I do look in every > so often just for peace of mind. I for one will never take that risk again > for the sake of roughly $2 a gallon difference. > Like Larry always says "your results may vary" but I doubt it... > Joe Horton > Dr. Deans plane ready for inspection..N657CJ > > > > > ------------------------------ > *From: *Kayak <[email protected]> > *To: *KRnet <[email protected]> > *Cc: *Kayak <[email protected]> > *Date: *Thursday, 4 December 2025 9:55 PM EST > *Subject: *KRnet> ethanol - anyone running it > > is anyone here running ordinary e10 ethanol car gas? > > just throwing out the question because almost all cars (including old > ones) are running on it, so it should be possible to accommodate it in an > aircraft. another option is to have a tank with 100ll just for > cristical flight phases like takeoff and climbout, and run the much cheaper > car gas off the other tank for the cruise phase... > > > > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet >
-- KRnet mailing list [email protected] https://list.krnet.org/mailman/listinfo/krnet
