TotalBoat Halcyon varnish can be applied directly to metal, as long as the surface of the metal has been prepared properly.
For all metals, the surface must be completely clean, dry, and free of any grease, oils, or waxes. Sand the metal with 220- or 320-grit sandpaper and remove any sanding residue. For metals that rust or oxidize, it is extremely important to apply TotalBoat Halcyon, as directed on the product, within 1 hour of sanding.