[becky'sdroptop]

POR-15 really needs to go to bare metal for best results. I have been using it since it first came out and have never had any rust return where it was applied properly. It really is designed to be top-coated with a good UV-resistant color coat if it is on surfaces that see direct sunlight.

We have used the chassis black for years with very good results. They have changed the formulation over time so that it is supposedly more UV-tolerant so that may not be an issue anymore.

For really tough topcoats I have been using PM Industries paint for a couple of years now. It seems to be less prone to chipping than POR-15 but will chalk out it not clear-coated.

WORD OF WARNING - POR-15 is a polyisocyanate so very good respirators with NIOSH-approved particulate filters are a necessity when shooting it. It is actually worse than Imron was for killing your lungs (know of at least one excellent painter that is now taking a dirt nap from his exposure over years with no respirator).

Paint has come a long way in being able to handle existing rust and staying adhered to less-than-perfect subsurfaces. POR-15 or PM Industries (I am sure there are others, too) will really help keep the rust gremlin at bay.