A method of manufacturing a porous structure for a fuel cell is disclosed. The method includes providing the porous structure, and processing the porous structure to selectively produce a non-porous region on the porous structure. In one example, the non-porous region is provided at the perimeter of the porous structure, an edge of an internal manifold and/or a surface or recess that supports a seal or gasket. The non-porous region has a porosity that is less than the porosity of the porous structure. The non-porous region prevents undesired leakage of fluid from the porous structure and prevents migration of adhesive associated with the seals.