Things You'll Need
Instructions
Purchase Brunswick-green or Pullman-green railroad spray-paint. German World War I helmets were a greenish-gray color. It might be necessary to replace the leather liner inside the helmet, and the chin strap. Replacements liners and chin straps are available online, and from some military surplus stores.
Clean the helmet with a mild detergent and warm water to remove dirt, grime and debris. Inspect the helmet for signs of rust. Apply Naval Jelly to the rusted areas. Allow it to penetrate the rust for a few minutes, and then wipe off the rust with a clean cloth. Rinse the helmet with clean water, and dry with a soft towel.
Sand scratches and blemishes with 600-grit sandpaper, using circular motions. Sand the helmet several more time, using a finer-grit sandpaper each time. Wipe the helmet with a clean cloth and mineral spirits to remove sanding dust and fingerprints.
Apply several light coats of metal primer. Use an aerosol primer. Hold the nozzle 8 inches above the helmet, and apply the primer with even and smooth movements. Allow the primer to dry between coats.
Apply the paint to the helmet with a paint brush. Create a textured or aged appearance by applying a light coat of fine sand or aluminum oxide to the helmet while the paint is still wet. Brush off the excess sand or aluminum oxide. Apply one more layer of paint.
Cure the painted helmet in an oven. Set the temperature at 130 F for two hours. Remove the helmet, and allow it to cool.
Attach the leather liner to the interior of the helmet. Connect the chin strap.