Rustoleum Universal Series - Dark Steel.
If you are going to paint anything with Rustoleum:
1. Sand surface smooth. If you can feel something it will show up after painting.
2. If surface is smooth to begin with, use some steel wool or scouring pad to swirl surface so primer will stick.
3. Clean surface with acetone or rubbing alchohol
4. Use a light coat of self-etching primer for aluminum. Darker primer is you are using a dark paint, and lighter if you are using light paint.
5. Wait 8+ hours depending on humidity for the first light primer coat to fully cure.
6. Finish up with one coat of the self-etching primer. It doesn't need to be thick--you actually want it as thin as possible. just get decent coverage.
7. This is where I see the biggest difference when using rattle cans. I wait a full WEEK for the primer to cure and harden. Sometimes more depending on how humid it is. If you decide that you don't want to wait that long your paintjob wont be as durable as the chemicals in the primer will weaken your top coat. Or something. I don't know...all I know is that is made a huge difference for me. Remember that dry to touch is not the same thing as fully cured.
8. wetsand the primer smooth.
9. Heat up your top coat can in a pot of hot water to 120-130 degrees.
10. While your paint is heating up, prepare your part on a piece of cardboard so you can rotate it easily. It also helps to have a fan nearby pulling air away from your part VERY gently. This will help you get a smoother finish.
11. Shake the bees out of the can. Don't be lazy here...you want a good mix. It helps if your panels are a bit warm too from the sun first or oven but they dont need to be hot.
12. Spray about the distance I did from that video you linked in even motions all the way through the part. The amount of overlap you want is from experience not science, but you do want some overlap. Practice on cardboard first. LIGHT FIRST COAT!
13. Wait four hours+ for the first light coat to dry. Go for another coat and aim for 60% coverage. Wait overnight.
14. Go for 100% coverage for next coat, but don't worry about evening the paint. Wait overnight.
15. Final coat should be just to even the paint. Don't touch it for two days. Just don't. If it is going to be installed against another part, you might have to wait 2 weeks to a month for it to fully cure depending on your climate.
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That's the easy part. The hard part is if you chose a paint not meant to be clear-coated, and if you are using Rustoleum then you probably have this type of paint. You might need to wet-sand slightly between coats if you got a really rough spray (but heating the paint and shaking well should dramatically help).
If you are clear coating it then you need to find a compatible paint. Don't just assume it will work because it is from the same brand and a clear coat. It can be really bad and your clear can crack or it will melt the underlying paint. You can apply the clear faster and thicker, but I still recommend the same process. You will need to wet sand and buff, and this is a multi-stage process in itself. If you plan on doing it on a S4 MINI panel...good luck. Those vents are a PITA.
Peace and good luck.
