Would you consider trying one more test? I've been wanting to do a test of E-10 -- the standard gasoline today that has 10% ethanol -- to see if "washing" it removes all harmful substances. It's well known that if you thoroughly thorough mix E-10 and water, you wind up with all the ethanol in the water, because ethanol dissolves in water and gasoline does not. This is the basis for a standard test (circulated by the EAA) for ethanol in gas by shaking it with water in a test tube.
I once tried this process on a larger scale, churning a 5 gallon bucket of E-10 and water with a toilet plunger (outdoors), and I was easily able to lower the ethanol content to zero. But I didn't have appropriate 0-rings and fiberglass chunks to test it with to see if it harmed the things on an aircraft, and I live in an area that doesn't sell ethanol-free gas so I couldn't buy samples to test it against. Your tests suggests that the manufacture of ethanol-free gasoline isn't done as carefully or as standardized as the national brands, maybe because the demand for it is so low. So if washed E-10 passed the same tests you put these other gasolines through, that could open up a source of affordable aircraft fuel to many more people. Mike Taglieri On Fri, Sep 7, 2018 at 12:34 PM, Jeff Scott via KRnet <krnet@list.krnet.org> wrote: > I thought I would make a followup report on the Mogas testing I have > conducted and the little bit that I have learned from it. > > I attached a photo of the same five jars of fuel after a month of soak > testing various parts that might be in the fuel system with some surprising > results, but more importantly perhaps an additional test methodology to > verify Mogas fuels for airdcraft use. > > In each jar, I place a new O-ring. Then I worked some pipe dope > (RectorSeal) into the threads of a 1/8" male pipe fitting and allowed to > cure for 24 hours before placing into the fuels. Then I laid up a single > sheet of tooling glass with aeropoxy and peel ply squeegeed out as thin as > reasonably possible and allowed to cure. After curing, I cut the fiberglas > into test strips and placed into the fuel jars for soak testing, one strip > with peel ply still on it, and one strip without and only one end of the > strip submerged in the fuel. > > The fuels in the picture are 1) 100LL as a control, 2) local > Conoco/Phillips brand 3) local unbranded independent fuel 4) local CITGO > branded fuel, and 5) local Murphy oil fuel that damaged my fuel systems as > my second control. > > Testing: > > The O-rings really don't show enough change to quantify at this point in > time. I'd like to think I can feel some slight differences, but it is not > sufficient for me to draw any conclusions as to damage to the O-rings at > this point in time. > > The fiberglass test strips in the three yellow colored fuels (3, 4, & 5) > and definitely showing signs of softening and degrading. When removed from > the fuel, it is visibly obvious which end of the test strip was submerged > in the fuel and the submerged end is starting to soften and the resin is > thinning between the weave of the glass. > > The pipe dope testing was very quick and probably the most telling. Jar > #5 dissolved the pipe dope from the threads of the fitting on contact. > That test was completed in a matter of seconds. Jars #3 & 4 both dissolved > the pipe dope as soon as I swirled the jar, so that testing was also > completed in a matter of 20 seconds or so. Jar #1 (100LL) and Jar #2 > (local Conoco/Phillips) neither one attacked the pipe dope on the threads > of the pipe fittings. After a month and repeatedly swirling the fuels, > Jars #1 & 2 still have the pipe dope intact in the threads of the > fittings. In the attached photo, I had just swirled the 5 jars. The > cloudiness in the three jars to the right is caused by the pipe dope in > suspension in the fuel. > > After a one month test, I think I have a winner for a Mogas I can safely > run in my planes. The local Conoco/Phillips brand fuel seems to be just as > innocuous to the various fuel system parts as 100LL. Of course it is 91 > AKI fuel with no alcohol and no lead, so will get mixed with 25% 100LL for > the time being to maintain the optimal amount of lead in the fuel for my > engines. > > In conclusion, based on the simple testing I have done here, in addition > to testing fuel for alcohol, I would also take a sample of the fuel and > test it against a pipe fitting with some dried pipe dope to see if it > attacks the pipe dope. If the pipe dope readily dissolves into the fuel, > you wasn to consider whether you want to run that fuel in your plane as it > may eventually wick it's way through any doped pipe fittings, may attack > any composite parts in the tanks, and may cause problems with rubber or > neoprene O-rings or seals in the fuel system. > > For those of us with Epoxy resin based fuel tanks, this is probably doubly > important. I will say the slosh compound I used in my KR tanks some 22 > years ago did save them from damage from the aggressive fuel I used, > otherwise I would also be cutting the tanks open in it as well. > > I have not yet repaired the tanks in my SuperCub Clone. I have been > waiting for cooler weather here in AR. I anticipate getting started on the > repairs after I return home from vacation following the KR Gathering. I > will post photos and descriptions of what I find after I cut the tanks open. > > -Jeff Scott > Cherokee Village, AR > > > > _______________________________________________ > Search the KRnet Archives at https://www.mail-archive.com/ > krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org > > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
