I have the formula on my web site
http://ca.geocities.com/[email protected]. To get the roughness, you spray the last few coats from a distance and by the time the paint hits the rim, the paint is 1/2 dry which causes the roughness. I know it's not the way the factory did it but it's hard to tell the diff. Also don't forget to mix mix mix the paint so the metallic makes the paint lighter.
