When I made a headache rack for my truck out of pipe and expanded metal,I used a thick nap roller and black rustoleum to paint it,then I sprayed any spots the roller missed with a rattle can..still sucked!..and yeah,it does waste a lot of paint!..
I used my ARC welder to tack weld the mesh to the pipes too,took a good hour to tack all of the nibs to the pipes..a mig would have been nicer for that job!..