I am attempting to paint a dryer drum. Typical Whirly/KM gray finish. It has the usual wear-and-tear knicks and scratches and developed some rust spots after sitting unused for a while. I don't have much experience with painting. Wire-brushed the rust, washed and thoroughly dried it. Using spray enamel, two coats thus far. Dried for several weeks, it's having a chalky residue that won't work so well for drying clothes if it doesn't clear up. I did not apply a primer coat first. Is painting a drum simply not workable, or is the technique at fault?