Messed up painting louvre, how to fix?

[uhhair]

So I recently attempted to paint my rear louvre with SEM trim black and I messed it up somehow. I have done this job on a previous car so I'm not sure where I went wrong or how to correct it. When looking at the louvre it appears to be streaky/patchy all over it. Is there a way I can fix this problem? I washed the entire louvre and degreased it when I started. Put on a coat, waited 10-15 minutes, repeated 3 times. Is it possible that the paint I used went bad? I purchased a few cans around 3-5 years ago but it was not used previously. Any advice would be appreciated, I'm just not sure where I went wrong or how to fix it.

[Michael]

Bleed through. Certain paints, primers, surfaces do not accept a coating equally. You need to have the same coating on the entire surface being painted, otherwise the paint will adhere differently to say a primed surface vs. a bare gel coated surface and give off a different sheen or color. Sand it down, put on a coat or 2 of good primer (on the whole thing). I use Dupli-Color or Plastikote brand filler primer but in the case of the louver, a filler primer is not really needed(doesn't hurt either). SEM also makes a good primer but I have not used it. Rattle can primer does not have a hardener but on a louver with no bodywork you don't have to worry about shrinking anyway.

SEM does not like to be sprayed in humid conditions. It relies on a rather fast flash time to make that matt finish we love so much. That said, you don't want to put in on in direct hot sun either. Several light coats to get the color, then follow up with one or two coats that are heavier but not "wet" like you would painting gloss paints.

[David T]

There probably was some kind of surface contamination (wax, silicone. whatever) or the paint reacted with the old paint. Sand, clean and apply a good primer compatible with what you are going to top-coat with. The primer creates a barrier between what you are putting on and what is already there besides giving you a good base for adhesion. You really should use fresher stuff too. Paint does not store well for long periods and since you used "rattle cans", if you didn't shake them enough you may not have mixed it thoroughly enough. It is also impossible to compensate for temperature and humidity since you can't mix or add anything to a spray can. About the only variable is the distance you hold the can away. Also sounds like you put too heavy a coat of paint on and if the 1st layers don't dry enough between coats the solvent will "pop" the upper layers.

[Michael]

There probably was some kind of surface contamination (wax, silicone. whatever) or the paint reacted with the old paint. Sand, clean and apply a good primer compatible with what you are going to top-coat with. The primer creates a barrier between what you are putting on and what is already there besides giving you a good base for adhesion. You really should use fresher stuff too. Paint does not store well for long periods and since you used "rattle cans", if you didn't shake them enough you may not have mixed it thoroughly enough. It is also impossible to compensate for temperature and humidity since you can't mix or add anything to a spray can. About the only variable is the distance you hold the can away. Also sounds like you put too heavy a coat of paint on and if the 1st layers don't dry enough between coats the solvent will "pop" the upper layers.

I'm just going to start singing my posts with your name...saving you the trouble of making another post with pretty much the same message.

David Teitelbaum

[Citizen]

Put on a coat, waited 10-15 minutes, repeated 3 times.

A picture would be helpful but without one, when I read this the first thing that came to mind was waiting on 10-15 mins seems incredibly short. I know you can get away with an hour or two using paint just for plastics, but I have never felt safe without letting coats dry over night and I get good results that way. Also, 3 coats seems like way overkill. Just saying.

I agree with what everyone else has said above as well. May also have somehow gotten oil from your hands on there after you cleaned it.

Thomas

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[Michael]

I agree what everyone else has said as well.

What everyone else has said, I agree with too.



David Teitelbaum

[cpistocco]

Paints can blush with high humidity...esp fast drying paints.

[gulwng3]

A picture would be helpful but without one, when I read this the first thing that came to mind was waiting on 10-15 mins seems incredibly short. I know you can get away with an hour or two using paint just for plastics, but I have never felt safe without letting coats dry over night and I get good results that way. Also, 3 coats seems like way overkill. Just saying.

I agree with what everyone else has said above as well. May also have somehow gotten oil from your hands on there after you cleaned it.

Thomas

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The flash time for SEM black is 3-5 minutes (per instructions on the can). You waited too long to recoat plus everything that Michael already said and David T. repeated.

"Flash-off time is the necessary waiting time taken to recoat or spray once a first coat is applied on a material. If the wait time is very long, it needs to be scuffed; if the flash-off time is short, irregularities in the paint job can be expected."

Andy

[Mark D]

I agree with what everyone else has said above as well.
...

What everyone else has said, I agree with too.


David Teitelbaum

[uhhair]

Thanks for the advice everyone! I'm going to sand it down lightly tonight and then give her a good rinse so she is ready to paint tomorrow. Regarding a primer, I have never used one before when doing this job. Is there one anyone recommends for use with the SEM trim black? Perhaps something I can obtain locally?