The present invention is directed to an improvement for a fill valve (22) for an aerosol container (10, 30) to provide better sealing capability. The fill valve is made using a flashless injection molding process in which both the mold cavity and molding material are heated to elevated temperatures to significantly improve cross-linking which occurs during the molding process. A backside (22a) of the fill valve now has a recessed portion (56) to facilitate ejection of the valve from a mold so leak paths are not created due to the forces applied to the valve during its extraction from the mold. The recessed portion reduces the amount of material required to make the fill valve and makes the fill valve flexible to aid in providing a good seal against leakage of a propellant from the container after filling.