The invention provides a single pass wet fabrication process for preparing a gas diffusion electrode for metal-air batteries and fuel cells comprising:a) preparing an active-layer forming dispersion containing catalyzed carbon black, hydrophilic fluorinated polymer and particulate hydrophobic fluorinated polymer in a liquid medium;b) preparing a blocking-layer forming dispersion containing carbon black and particulate hydrophobic polymeric binders in a liquid medium;c) filtering a first of the layer forming dispersions though filtering means to deposit a first layer of damp solids mass;d) filtering a second of the layer forming dispersions through the first deposited damp solids mass before the drying or sintering of the first deposited damp solids mass in order to deposit a second layer of damp solids mass thereon in such a manner that lower components of the second layer of damp solids mass are intermixed with upper components of the first layer of deposited damp solids mass;e) drying and compressing the composite first and second layers with a conductive metal mesh incorporated therein; andf) heating the dried layers to a temperature above the sintering temperature of the hydrophobic polymer while applying pressure thereto thereby causing the polymeric materials of both layers to sinter and bond with each other and with other components of the layers.