Just to amplify on Les’ post : What is the big deal with painting salvaged metal?

For one, the salvaged metal must be stripped of all the old paint, and rust. This involves using paint strippers and chemicals that definitely add to the “carbon” load of the planet. And then applying a primer, and then painting over it. The labor, and cost involved can deter most users.
Using Black Permalac EF, a low VOC black coating allows many of these steps to be taken away. No need to strip the paint or rust, and no need for a primer. Metals that would have prohibitive to re-treat, can now be reused easily.