A method of forming a plurality of fasteners includes extruding a continuous strip of material, the continuous strip defining a base portion, a tip portion, and a stem portion extending between the base portion and the tip portion. A portion of material is removed from the continuous strip of material along the tip portion such that a plurality of tip portions are separated from each other and spaced apart, each tip portion having at least one flexible tab. The continuous strip of material is then extruded through a foaming die, wherein the flexible tabs are elastically displaced away from the base portion during a foaming process such that a foam material fills a cavity of the foaming die to form a sealing element around the stem portion. Portions of the continuous strip between each of the tip portions are separated to produce a plurality of individual sealed fasteners.