[HitmanHearns]

I got a question about spray painting an m sport rear diffuser. The material is polypropylene so I bought a gloss black spray paint that is used on that material (states on the back of the can). I purchased Rust Oleum gloss black spray can.

So I ended up spraying the diffuser and the color came out non-gloss. I gave it a few base coats. I let it dry and applied the clear coat Rust Oleum spray (which is supposed to add the gloss) an hour later and it immediately caused the paint to discolor (started having white spots and mis match spots all over).

I have no experience in spray painting car parts so I had initially asked how long to wait between base coat and clear coat. I was told 30 mins to an hour. I went to autozone to buy more base coat paint and 2000 wet sand paper and the worker said you must wait 24 hours before appling clear coat no matter what.

I ended up sanding the diffuser the best I could and applied the base coat. Only one section I really want to spray more (ran out spray paint yesterday).

Could I apply another set of base coat on the diffuser or is it to late? Also what is the window/time frame before I apply the clear coat.







Also, I was thinking about removing all the paint and starting over but every paint remover had warnings to stay from plastic. Is it possible to remove paint from polypropylene?

[wdeerfield]

did you prime the surface first?

[HitmanHearns]

Originally Posted by wdeerfield

did you prime the surface first?

No I did not. I think I failed by asking people at auto zone for advice -_-

Would I need to prime this material?

[HitmanHearns]

I just bought Primer, the same black spray paint (gloss), 400 wet sand paper and 2000 wet sand paper.

I also have clear coat at home.
Should I do the follow?

1)Sand it down with 400.
2)Apply primer
3)Sand it down with 2000 where necessary
4)Apply black gloss coat
5)Wait 24 hours and apply clear coat

[HitmanHearns]

One more thing...the primer I got is sandable black primer. Is this fine or would I need a clear primer?

My ideal end result is a gloss look.

[wdeerfield]

sandable black primer should be fine. your steps seem to be what id do but i have never painted car parts.

i would sand in between the clear coats as well with at least 800grit.

[HitmanHearns]

Originally Posted by wdeerfield

sandable black primer should be fine. your steps seem to be what id do but i have never painted car parts.

i would sand in between the clear coats as well with at least 800grit.

Awesome. I sanded the previous base coat with 400 grit wet sand paper. Surprisingly it took A LOT of paint off. I went ahead and applied a few coats of primer.

It's been 20 minutes since I've finished. I think I will let it dry for 24 hours (even though it drys I think in 10-15 minutes) before I sand and apply the base coat.

Thanks for helping me out!

[HitmanHearns]

Some pictures below. Honestly, the primer looks so freakin good I want to leave it this way hahahah

[HitmanHearns]

UPDATE:

Clear coated the diffuser last night and no shine this morning. The color also got a little less black (less darker).

It might be time to give up and let a professionally do it?

[LIVY435IGC]

I tried the same thing with my front lip with no success awhile back.
I used some vinyl wrap in the end at came out good.
Good luck

[HitmanHearns]

Originally Posted by LIVY435IGC

I tried the same thing with my front lip with no success awhile back.
I used some vinyl wrap in the end at came out good.
Good luck

That's what I'm planning on doing !!! What vinyl wrap Did you get?

[kpeng]

Ok wow...why did you attempt this when you had no experience painting?

Clean the hell out of it, primer...wetsand the primer...base coat...wet sand the base coat...2nd coat...then clear...wet sand...clear. Allow ample time in between coats to dry (look on the can)

I would suggest using a lacquer paint if you want something super shiny.

[HitmanHearns]

Originally Posted by kpeng

Ok wow...why did you attempt this when you had no experience painting?

Clean the hell out of it, primer...wetsand the primer...base coat...wet sand the base coat...2nd coat...then clear...wet sand...clear. Allow ample time in between coats to dry (look on the can)

I would suggest using a lacquer paint if you want something super shiny.

The diffuser was free and I'm an idiot 50% of the time. Can you suggest what spray can brand? Just so this time I don't make any errors.

I did all the steps above except sanding the base coat and sanding after the clear.

What # wet sand paper? Same # for all coats? Also the spray I used was made for polypropylene. Does it matter if the spray can is not made for the material?


When I first painted it I painted it gloss black with duplicolor and it was the color I wanted. The spray can got damaged so it squirt all over the diffuser and it had runs. I sanded it next day and applied the black gloss from rust oleum that's made for polyproplene but it was never gloss. I even tried to respray the gloss black duplicolor over the diffuser but it didnt even pickup the color!!! After all this happened, I ended up sanding it all the way down, priming than posted the thread.

Is this irreversible?

[grancoupef36]

ok......THIS IS WHAT YOU HAVE TO DO, from experience

sand it first with 400 grit..
prime it, 3/4 coats will be good
wait for primer to dry a day or few hours will do
wetsand the primer with 600 grit.. till smooth
then hit it with the base coat, do not sand the basecoat
3/4 coats again
wait for that to dry, it'll say on the can but its usually an hour . you can clearcoat once its dry to the touch

then clearcoat and hit it with 3/4 coats again

after you let the clear dry for 24 hours, it'll have an orange peel effect and THIS is when you hit it with the wet sand. first start with 1000 grit , make sure everything is wet and BE CAREFUL when sanding around edges and grooves. its really easy to take off too much in those areas. when sanding you'll start to see the water change color to a milky color. thats normal cause thats clearcoat coming off. rinse off and if you feel its smooth to the touch hit it with the 2000 grit, wetsand again. with 2000 grit, were not trying to remove the orange peel but rather the scratches from the 1000 grit. try it get it under some light to see. THEN after all that , you need to POLISH the clearcoat thats what will give it the shine. you can use meguiars polish kit, with a polishing drill attachment. would be hard to use an orbital buffer on an object like that. then you're done. long process but thats what it takes to make it glossy