Not fuel or eth. resistant, balloons & releases adhesion. The only product we found that holds up is Proseal, had our tanks fueled with mogas/eth./2 cyc. mixture, Proseal & Vans Aircraft supplied Slosh was unaffected. Do not use Tight-Seal or Permatex #2 as they both failed tests in short order, alc. washed away solvents in both products & leaves a gray powder.  David Cook RV6A (USA up over in Michigan)  (tanks resealed, waterpump replaced, ready for eng. start & taxi-testing)