metallic paint technique ?

Single stage or basecoat/clearcoat system???

If it's single stage, they can be a real PITA sometimes depending on the color. I usually only do single stage for solid colors and BC/CC for all metallics. When you try to paint a single stage metallic you are sometimes fighting two competing requirements, coverage and gloss versus getting the metallic to lay down uniform without "tiger striping". That's the beauty of BC/CC, you can spray the basecoat in multiple coats, get coverage, and do a low pressure metallic equalizing coat last, then let it flash, and pound on the clear giving only consideration to coverage and gloss at that point. BC/CC will cost you more than single stage, but you get what you pay for.