Thermal curable compositions contains a glycidyl ether epoxide resin, a carbinol functional silicone resin or an anhydride functional silicone resin, and a thermal catalyst. An organic polyol, an organic anhydride, and filler, are optional components that may also be included in the composition. The glycidyl ether epoxide resin adds toughness and adhesion to the composition, whereas the carbinol functional silicone resin and the anhydride functional silicone resin provide water resistance, weatherability, thermal stability, and flexibility.