Vinyl ester has slightly better durability for 100 LL aviation fuel. Epoxy is satisfactory also for 100 LL. Both resins will dissolve slowly in the Ethanol that our enlightened government requires to be added to automotive gasoline. In the presence of water in the Ethanol laced fuel, the Ethanol is much more active and will dissolve Vinyl ester quite quickly. (Been there, done that, got the aluminum tanks.) The water is absorbed by the Ethanol that is stored in vented gas station and aircraft fuel tanks until it reaches 6% water at saturation. All the chemistry experts I checked with refer to this condition as a super solvent for Vinyl ester.
No mechanical filter will separate the dissolved water from the Ethanol. Rubber components in aircraft fuel systems are also attacked by Ethanol. Worst case is the hardening of the tiny rubber tip on the float needle for float carburetors. Recommend that Ethanol automotive fuel not be used in Vinyl ester and Epoxy aircraft fuel tanks. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ++++++++++++++++++++++++++++++++++++++++++++++++ My M-19 is being constructed using the pink board and AeroPoxy laminating >> resin, but the wet cell wing fuel tanks will use vinylester for fuel >> resistance. >> >> Oscar Zuniga
