Electro Deposited Paint, is the correct terminology and has gotten a bad name within the industry due to a couple of factors.
First, some manufacturers use lacquer-based coatings that are sometimes mislabeled as EDP. Lacquer is porous, allowing water absorption and subsequent rust formation beneath which leads to premature failure and must be removed. You can check by putting some lacquer thinner on a rag and wipe the black coating. If it smudges or gets on the rag, sand it all off.
Secondly, authentic EDP coatings lack UV resistance and will deteriorate over time when exposed to sunlight. Should you observe any signs of coating failure, it is essential to remove the affected layers.
However, EDP cannot be left as a final finish. Therefore, all EDP-coated parts must be top-coated with a UV-resistant finish to ensure long-term durability.
If neither of these conditions exist, then they are suitable as a base coat. Scuff it with 220-320, apply an Epoxy primer then finish as usual.
