Duracoat is one of the easier DIY options for a tough finish that is extremely chemical resistant. Cerakote is another option, but is a bit more complcated due to the need for baking the finish.
If you already have a compressor, you can get a Harbor Freight airbrush for about $9.00 that will work well enough for most duracoat applications. Pick up a quart of laquer thinner as well for cleanup. Like most paints, the basis for a good duracoat application is all in the prep work.
U.S. Navy (Retired) 1994-2015