Abstract: The invention is directed to a direct manufactured fuel cell plug, preferably used with aircraft fuel tanks or bays, comprising a digitally manufactured part, wherein the fuel cell plug is designed to securely fit into and seal an opening to be sealed in a fuel tank to eliminate all substantial gapping between the fuel cell plug and the opening. A sealant material is applied to the fuel cell plug prior to securely fitting and sealing the fuel cell plug into the opening. The invention is further directed to a method for sealing a fuel tank or bay, preferably in an aircraft. The method comprises the steps of applying an adhesive sealant to all faying surfaces of a direct manufactured fuel cell plug, positioning the sealant applied plug into an area to be sealed in the fuel tank, and spraying the entire sealed area with a spray sealant.