Harry - lots of folks use a brush/roller to do a thrifty paint job, some use tractor enamel from a farm supply, some use Rustoleum, some use house paint .... I've done a big bus with a roller for large areas and a brush around the edges or where the roller doesn't reach -
looky here ... I used Zero Rust, which worked well if you don't mind the mat finish, although they have a clear coat used for UV protection that gives a smoother finish
best to do a proper job of sanding including taking it to bare metal where necessary - the final job will reflect how much prep you put into, if you're trying to avoid any sanding at all might as well skip the paint, won't last long
Bill
