An experiment in rust.

[Dave Harris sctchbld]

The green one looks too much like mud. You're not just going to get an even coating like that. Rust causes pitting, and usually in clusters.

OK We need pitting. Perhaps I have an answer for that. this hood was sanded on one side--- put in ferric-chloride a few minutes to see if it would eat it up like it does copper & aluminum --- it does ,not as fast but enough.
After soaking a bit I resanded the pitted side & sanded the still painted side for a comparison. Take a look at the results.
I think after adding some paint they should look convincing?