I hear you guys on the paint prep--my questions is what to use for it. This is a 50 year old boat that a friend got when his father in law passed away. It has existing olive paint of unknown age and type, and has been sitting unused long enough to acquired some lichen and moss growth on the side that was in the shade. (This actually makes for an outstanding camo pattern that I almost certainly can't reproduce.) So an extensive sanding job is in my future, and that will almost certainly leave me with some bare metal and some spots I am putting new paint over old. I'll evaluate the need for a complete coat of primer over everything based on how much bare metal vs. sanded paint that's adhering well when I get there. But for the bare metal, it seems to me there are at least three possible approaches. (1) Use some version of an automotive metal primer as Eric suggests. I don't have a paint sprayer--my plan is to roll the finish coat on. There are a bunch of rattle can metal primer paints out there that might be an option. I don't see myself investing in a quality paint gun for this small job. (2) Use a self-etching primer paint. This is what Lou suggests on his instruction page, but he references a couple of products that seem to no longer be available. One similar product--there are many similar--would be this:
https://www.nationaltoolwarehouse.c...dwhfBrRGvYoHuHLyLz4Sa61VPhAT7x7hoCy9AQAvD_BwE (3) Use an etching wash on the bare metal, followed by either a standard primer coat or just a first coast of the FME. As I understand it, these are applied to bare metal, allowed to dry, and then must be painted immediately before the aluminum oxidizes again. One product is this:
https://www.totalboat.com/products/...FDdA0uCb_s2cLgO_QHdreeFjM--soiWhoCJyIQAvD_BwE
I'm probably overthinking this. For my purposes just sanding and applying over the existing paint would probably be fine, but either self-etching primer or an etching wash would result in something more durable and better looking. But any thoughts on acid etch vs self-etching primer paint would be welcome before I follow Carl's advice and just slap on some fresh paint.