Maybe the question should not be whether polyester is useable for a gasoline tank, but which one works "best". Back when I researched fuel tank resins I read that vinylester was practically designed to be resistant to gasoline and it's additives, as well as other chemicals that were difficult to contain in more common polymers.
A quick Google search using "polyester chemical resistance" yielded http://www.engineeringtoolbox.com/chemical-resistance-polyester-d_784.html , which isn't very reassuring at higher temps, and for vinylester, http://www.engineeringtoolbox.com/chemical-resistance-vinyl-ester-d_785.html , which fares much better, as do most of the other chemicals shown in the charts. Most homebuilt aircraft composite sources say to use vinylester, and that's good enough for me. I would think "better" is desired over "acceptable". I suppose if a guy wanted to save a few bucks by buying polyester at Walmart as opposed to vinylester from somewhere like Aircraft Spruce that's his tradeoff to make, but if you're doing it for weight savings, I think you're using the wrong reason... Mark Langford N56ML "at" hiwaay.net website at http://www.N56ML.com --------------------------------------------------------
