valve cover paint issues

spederman · Jun 23, 2009

I decided to paint my valve covers with some cast aluminum paint (rattle can). I prepped really well with a degreaser/cleaner, then took some red scotch brite pads to it and used plastic primer, then sprayed with 3 coats of the cast alum paint. Humidity/outside temps were fine when i painted. I was looking at them today and if you even nick the paint with your finger nails, it chips off. WTF? Did i do something wrong or is it just cheap ass paint? (plastikote cast alum)

MustangLX-5.0 · Jun 23, 2009

When did you paint them? Shouldn't chip that easily. I have sprayed paints that were not even meant for plastics..on plastics and they didn't chip like that. Though they will crack and peel more easily. As for Plastikote, I hate to tell you this but....... Cheap! Really. I tried that stuff at Autozone years ago. I'm an avid spray painter and have learned the hard way about paint brand quality. Plastikote imo seems way too runny. Too thin. I have always used Duplicolor or DuPont spray paints since then. You may wish to do so also. Duplicolor paints are always well mixed and not too thin. The spray pattern is more of a pro type spray gun. And the paint itself is more pro quality. Seems to last a lot longer than anticipated. Oh and that reminds me, did you shake it up well?

spederman · Jun 23, 2009

MustangLX-5.0 said:
When did you paint them? Shouldn't chip that easily. I have sprayed paints that were not even meant for plastics..on plastics and they didn't chip like that. Though they will crack and peel more easily. As for Plastikote, I hate to tell you this but....... Cheap! Really. I tried that stuff at Autozone years ago. I'm an avid spray painter and have learned the hard way about paint brand quality. Plastikote imo seems way too runny. Too thin. I have always used Duplicolor or DuPont spray paints since then. You may wish to do so also. Duplicolor paints are always well mixed and not too thin. The spray pattern is more of a pro type spray gun. And the paint itself is more pro quality. Seems to last a lot longer than anticipated. Oh and that reminds me, did you shake it up well?

I just painted them last week. Oh well, i guess i can sand them down again and throw some more paint on them. Stupid cheap ass pastikote junk. And yeah, i shook the hell out the can every minute or so. I'll go with duplicolor. The only reason i bought the other stuff was because i couldnt find a dull aluminum color that was high temp resistent in any other brand.

iskwezm · Jun 24, 2009

sand them down and use a self ecthing primer that will adhere to the aluminum. I just painted my wheels and they are holding up fine.

spederman · Jun 25, 2009

I dont know about using the self etching primer on stock plastic valve covers though. Isnt that stuff only for metal? I got some adhesion promoter and some duplicolor cast alum paint. Hopefully it works better than before.

MustangLX-5.0 · Jun 27, 2009

iskwezm probably thought your valve covers were aluminum. Mis-read info. Heck I thought they were aluminum till the paint started peeling off mine.

You didn't sand the surface down too fine? Should be no more than 600 grit. And when the paint peeled,did it peel all the way to the plastic or just to the primer? Duplicolor has a aluminum textured paint in the high temp paint. To be more specific,the 500 degree rated paint, not the ultra high temp paint meant for headers etc.

spederman · Jun 27, 2009

i used the scrotch brite red pad to sand. I used the clear plastic primer before so i couldnt tell if scratching was going thru the primer or not. The adhesion promoter clear that i got now is made by duplicolor also. That stuff counts as a primer, correct?

MustangLX-5.0 · Jun 29, 2009

spederman said:
i used the scrotch brite red pad to sand. I used the clear plastic primer before so i couldnt tell if scratching was going thru the primer or not. The adhesion promoter clear that i got now is made by duplicolor also. That stuff counts as a primer, correct?

Yeah, for plastics. Regardless of paint used, make sure there's not excessive moisture or dew out. In a garage..thats fine.

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valve cover paint issues

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