My dear old dad paited a couple of work trucks with enamel. A red one looked good because he took his time. The second was just OK cause he was a lot older and didn't work much on it. He said back in the 30's and 40's all cars were painted with enamel, oil base. He used gasoline for a thinner (not recommended) and a devill bliss spray gun. Did it in the open drive way.
