A filleting compound for sealing integral fuel tanks and pressurized cabins. It was especially developed for use over a temperature range of -65F to +275F and provides outstanding resistance to aircraft fuels (aviation gasoline or jet fuel) and petroleum base lubricating oils. Cures at room temperature and without shrinkage to form a resilient sealant possessing excellent adhesion to aluminum, magnesium, titanium, steel and numerous other materials.