Risk Reactor Inc.'s black light clear paints are coatings that can go on clear and then show the listed color under black light. The clear red and clear yellow and green all require 365 nm. The clear blue accepts a wide range of ultra violet energy and can be used with up to 405 nm lights. The clear uv neon colors such as the CF2-C0 will look blue even under sunlight or indirect sunlight due to its wide range of ultra violet energy responsiveness while the clear red and other colors will not. These are more specific to the exact wavelength to be excited.
Yes we have inks for metal. CF2 is a thicker coating and leaves more like a paint while the IF2-C0 is thinner How do you want to mark the surface? How do you want to mark them? Keep in mind the metal might have oils during manufacturing and some testing would be in order. Use IF2 series for marking most metal. Have the MAR-C0 Invisible Blue marking pen handy and always try this one first since it is so easy to work with. To mark you parts you can dip, use MRA-X refillable pens, paint brush, etc.