I don't think it'd rust through in your lifetime!
That being said, if you want to prime it here's what I'd do. Strip the hood to bare metal on top (and underneath if you are truly ambitious) and sand with 80 grit. Prime with epoxy, let it set 3-5 days to try and become fully cured, and re-install.
If I recall correctly, epoxy in direct sunlight is good for 3-5 years. I don't know if you are planning on painting it down the road, but you'd have some time.
You could sand through the rust spots and scuff the rest of the hood with 80 then coat, but you are relying on the original paint for adhesion. It wouldn't be as solid down the road if you decide to paint.
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I don't think it'd rust through in your lifetime!
That being said, if you want to prime it here's what I'd do. Strip the hood to bare metal on top (and underneath if you are truly ambitious) and sand with 80 grit. Prime with epoxy, let it set 3-5 days to try and become fully cured, and re-install.
If I recall correctly, epoxy in direct sunlight is good for 3-5 years. I don't know if you are planning on painting it down the road, but you'd have some time.
You could sand through the rust spots and scuff the rest of the hood with 80 then coat, but you are relying on the original paint for adhesion. It wouldn't be as solid down the road if you decide to paint.