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Unread 07-24-2013, 10:39 AM   #1
NissanGuy23
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1996 ZJ 
 
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Location: West Chester, PA
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Help with blotchy paint

My rear ZJ vents were worn out and faded, so i decided to repaint them. I removed them, sanded down with 120, swiped with alcohol, gave it a primer coat, hit it with light even coats of dupli-color perfect match paint which is meant for auto trim applications. Every time it ends up looking like this - weird/dull/blotchy. Frustrating, im just going to do it flat black if i cant figure out what the issue is.

Thanks for any insight

Pic:
http://img835.imageshack.us/img835/2135/caod.jpg

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Unread 07-24-2013, 04:22 PM   #2
goldhammer
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I would resand with 320, reprime and 320 again, then hit with medium wet coats. If metalic, the last coat hit it in a "crosshatch" pattern with light coats. About a 45* angle each way and about half the amount in each direction as the coats before. Each direction, as soon as you finish one way immediately go the other.
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Unread 07-26-2013, 10:59 PM   #3
magnetman
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No offense but It looks like your spraying like shooting a water gun.

Are you dong long strokes with the spray can? When you finish each coat you need to see a uniform wet look over the surface. It may be that you are just not spraying evenly with heavy spots where the splotches appear?
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Unread 07-27-2013, 07:02 AM   #4
ToledoDave
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Looks to me like maybe you didnt sand the primer? With the primer not sanded or well enough it will give that rough texture for one and it will also absorb the paint like a sponge and not lay on top and look like it does. If that doesnt help i would get some (i think its name is ) Bullydog etching primer to adhear to the plastic before shooting color. If your looking for flat type finish then dont sand the primer and spray with lots of light coats giving 3-5 minutes between coats. If you want glossy then sand the primer and spray heavy wet even coats and at least 5 minutes between coats dont wait too long though between coats as additional coats need to be chemically burned in during the window of oportunity (flash period). Hope that helps ya

Also i believe those vents are plastic? Dont use 320 on them unless your carefull. Get yourself some scotchbrite pads. And scuff them and the primer real good by hand. If you have to use any sandpaper i would use mayby 500 grit if any. Scotchbrite pad will do wonders for ya.
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Unread 07-28-2013, 10:32 AM   #5
NissanGuy23
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Thanks for the info. I ended up doing them flat black though. I was using even/ long strokes, the paint went on smooth but after drying it became blotchy. I didnt however sand the primer. Im
No paint expert but i mainly wanted to remove the old faded peeling paint so job done.
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Unread 07-28-2013, 11:03 AM   #6
ToledoDave
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Understandable. Thats what happens if not sanded. It soaks the paint up like a sponge and leave dry looking spots. Hope it works out for ya either way and good luck and happy trails!
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Unread 08-01-2013, 05:30 AM   #7
ontarioXJ
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Sand, wipe with a prep wash or thinner not alcohol. Your not installing a sticker , the alcohol that could have been absorbed in the sand scratches could have that effect on it when the paint tries to cure. Light coats of primer with some sanding in between with a 320 grit. When all is said and done blow it clean and tack rag it before paint. Lay a few light coats to desired finish. Leave it cure for the day if need be.
If you find the can of paint cool or anything, a trick is to keep the can of paint you are gona use in a pail with some hot/warm water. Mix every so often. It helps keep all the paint molecules consistent and believe it or not you get a better result. (Aerosol paints)
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Unread 08-07-2013, 12:45 AM   #8
swirve
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Quote:
Originally Posted by ToledoDave
Looks to me like maybe you didnt sand the primer? With the primer not sanded or well enough it will give that rough texture for one and it will also absorb the paint like a sponge and not lay on top and look like it does. If that doesnt help i would get some (i think its name is ) Bullydog etching primer to adhear to the plastic before shooting color. If your looking for flat type finish then dont sand the primer and spray with lots of light coats giving 3-5 minutes between coats. If you want glossy then sand the primer and spray heavy wet even coats and at least 5 minutes between coats dont wait too long though between coats as additional coats need to be chemically burned in during the window of oportunity (flash period). Hope that helps ya

Also i believe those vents are plastic? Dont use 320 on them unless your carefull. Get yourself some scotchbrite pads. And scuff them and the primer real good by hand. If you have to use any sandpaper i would use mayby 500 grit if any. Scotchbrite pad will do wonders for ya.
Nothing wrong with 320 dry. Scotch bright pads are coarser than that and produce an uneven scratch. For raw plastic you should use a light grey mirlon thats been unfolded and then lightly scuffed. If the plastic has already been painted which i think it has, the whole plastic prep thing doesnt matter.
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Unread 08-10-2013, 06:33 AM   #9
ToledoDave
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Quote:
Originally Posted by swirve View Post

Nothing wrong with 320 dry. Scotch bright pads are coarser than that and produce an uneven scratch. For raw plastic you should use a light grey mirlon thats been unfolded and then lightly scuffed. If the plastic has already been painted which i think it has, the whole plastic prep thing doesnt matter.
Swirve...I beg to differ. Scotchbrite is not courser if useing the right pad. 320 would not be a good option reason why because generally 320 is use with a D/A and d/a sander on flat surface plastics is tricky enough let alone the louvers. He could and probably would burn an arse hole into the plastic. If you choose to hand sand 320 you are more likely to leave lines then with a scotchbrite pad. remember hes inly scuffing for paint not sanding anything.Since your only preping the panel for primer and or paint and not sanding scotchbrites are more then enough. Also in the OP and first statement, he stated he already primed and painted the part. His chief complaint was the dry look. To correct the dry look he needed to sand the primer prior to laying color in which later explained he did not. Now in my statement I suggested he scotchbrite the primer before painting and that would eliminate his dry paint look. If he used a fill and sand primer and attempts to paint over his 320 hand sanded primer his paint will never fill the lines. He needed to scuff his primer and or wet sand it by hand to make it smooth and rdy for paint. Since he cant d/a the plastic he will have to hand sand the parts. Hand sanding 320 will cut like an Iceburg.
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