Civic Forumz - Honda Civic Forum - Steps on Painting aftermarket (pastic) car parts: Professional

Painting Car Plastic Parts, step-by-step, using the 1-stage process

(note: 1-Stage is when the gloss is already mixed in with the paint. 2-Stage process separates the colour application from the gloss application, whereas the 1-stage combines the two into one)

1.Do not sand the plastic itself -- rather, fill the holes/blemishes with putty and then smooth it out with fine sandpaper (400-grit, 600-grit). By sanding the plastic you release the internal silicon that exists in all plastics, and paint/primer will not stick to silicon. Old plastics do not have silicon on the surface because the weather has worn it off, but once you sand it, you are effectively peeling back the "dead" layers of plastic and revealing the silicon-rich "fresh" plastic.

2.If necessary, use chemical plastic cleanser (follow instructions on can) to remove all silicon from the plastic surface. This will be required if 1) you have already sanded by accident; or, 2) the plastic is new. To ensure a correct decision, perform a test -- apply some primer on the surface to be painted, wait for it to dry, and then try scratching it off with your finger nail. If it comes off easily you're gonna need to use the chemical cleanser. If it doesn't come off use discretion whether to use chemical cleanser -- sometimes it's just not required at all. Rely on the test to make your decision.

3.Once the plastic surface is silicon-free and clean, spray on the adhesive enhancer following instructions on can. This product will help the primer bond to the plastic better. NOTE: all those cars on the road that you see with paint peeling off the bumper and other plastic parts -- the reason it happens is because the painter didn't follow steps 2 and 3.

4.Now it's time for first primer application. For plastic car parts, be sure to use flexible primer as car plastic bends under normal operating conditions and the primer will need to be able to bend with it without cracking. Apply primer and let it dry to a touch (a few minutes). Apply next coat of primer and again let it dry for a few minutes. Apply your final coat of prime and let it dry. Sand (very lightly) with 600-grit sandpaper to remove the orange-peel effect. The purpose of sanding after the prime coats is not to sand through the primer into the original plastic. Rather, the purpose of sanding is to remove the orange-peel effect i.e.: inconsistencies in the paint elevations.

5.Clean (very lightly, with minimal contact of tack cloth to surface) with tack clock to remove dust. Now it's time for the second primer. Any additional primer should follow the method of steps 4 and 5 until you are satisfied with the surface -- it must be PERFECTLY smooth -- after the last prime, we cannot go backwards. This is the last time you can verify the smooth surface before painting.

6.Paint is mixed in a ratio of 4:1:8, that is 4 parts paint to 1 part hardener to 8 parts reducer (aka thinner). The ratio of paint to thinner (4:8) is not as critical as the ratio of paint to hardener (4:1). Hardener will not harden the paint correctly if too much or too little is mixed, so make sure this measurement is dead-on. The measurement of reducer might be a little too high, so maybe start with a little less and mix in more if you need it -- remember, you can never remove reducer that you've already added, so start low and work up to the full 4:8 amount of reducer.

7.Prepare the paint gun, ensuring that the correct amount of thinner is mixed to ensure a consistently smooth spray pattern. Now begin painting. Multiple coats of paint will be required (3 coats), with 15 minutes drying time between each coat. Do not sand in-between coats. Do not stop in the middle of a coat. Avoid overspray and drips.

8.Once done, let the paint cure for a long time (see can) before moving/using it. Do not wax the newly painted surface for 30 days. To help solve the very noticeable difference in gloss between the newly painted parts and the old parts, wash the car (before installing newly painted part) and use a high-gloss wax to shine-up the areas closer to the soon-to-be-installed newly painted area -- this will make the differences in gloss less noticeable. Over time, the gloss will lose some of it's shine and will match the rest of the car.

NOTE: car paint is extremely hazardous, more so than lacquer thinner. Wear goggles and breathing mask (important). Full-time professionals wear a full body suit to protect themselves. Also open doors/windows to allow air circulation.

+Maafeustyle :)