[villagetinker]

Good luck with this. This will a be a complicated project if you intend to leave the screen on. I would not attempt a brush paint job. Since the existing paint is oxidizing you will need to use TSP or equal cleaner, probably a high quality primer, and then to final coat of a high quality outdoor probably gloss paint. With the screening removed (or planned on replacing after painting) all of the above can be done by spraying, much faster and typically better coverage than brush. Be very careful about wind as you could end up painting the neighbors house or car.