NOVELTY - A composite seal (206) comprises a base layer formed from an elastomer constituent; and a protective layer formed from a fluoroelastomer or fluoropolymer constituent, where the protective layer is applied over the base layer to coat the elastomer constituent.    USE - As composite seal; for constructing a composite seal on a component; for sealing two component parts (claimed); and in fuel cell applications.    ADVANTAGE - The composite seal provides superior sealing performance and durability in proton exchange membrane (PEM) fuel cell applications.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) constructing a composite seal on a component involving loading the component into a holding fixture; applying a primer along a periphery of the component; dispensing an elastomer constituent directly onto the primed periphery of the component, the elastomer constituent forming a base layer of the composite seal; and applying a fluoroelastomer or fluoropolymer constituent over the elastomer constituent, the fluoroelastomer or fluoropolymer constituent coating a surface of the elastomer constituent to form a thin protective layer over the base layer; and    (2) sealing two component parts using the composite seal involving loading a first component part; applying a primer along a periphery of the first component part; dispensing an elastomer constituent directly onto the primed periphery of the first component part, the elastomer constituent forming a base layer of the composite seal; applying a fluoroelastomer or fluoropolymer constituent over the elastomer constituent, the fluoroelastomer or fluoropolymer constituent coating a surface of the elastomer constituent to form a thin protective layer over the base layer; loading a second component part, where a periphery of the second component part is aligned with the periphery of the first component part having the composite seal formed on it; and joining the second component part to the first component part along their the peripheries, sealing the first component part and the second component part together.    DESCRIPTION OF DRAWING(S) - The figure shows a view of a variety of bipolar plates for use in proton exchange membrane (PEM) fuel cell applications having the composite seal deposited on it.    Bipolar plate (204)    Composite seal (206)    Applicator (304)