Blackfriar Multi Surface Primer White Matt Finish - 1 Litre. This water-based primer is suitable for interior and exterior use, offering anti-corrosive protection. It dries to the touch in 1 hour and can be recoated after 4 hours. The primer covers approximately 12m² per litre per coat. It is specially formulated to prime and seal a wide range of surfaces including soft woods, chipboard, plywood, GRP, MDF, exterior UPVC, ceramic tiles, iron, steel, galvanised and non-ferrous metals (aluminium, brass, chrome, copper), and old plaster. Stir thoroughly before use. Apply one coat by brush or roller, except on ferrous metals and porous surfaces where two coats are recommended. Ensure surfaces are clean, dry, and free from wax, grease, and oil before application.