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Discussion Starter #1
Here's another question on painting. I used to know all this, but that was when primer was just primer, and a good paint job was Lacquer in 20 coats sprayed on and 15 sanded off.

I've got the basics: etch primer on bare metal, then epoxy primer for a great base. Filler and high build primer, with a few boxes of sandpaper for a perfect surface.

Now the color/clear coats. I understand these 2-part finishes have a fairly thin color coat, and a "thick" clear coat.

Is the base color coat color sanded? Or does the clear just go over it, which is then color sanded (for orange peel and other issues).

Robert
 

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Don't need to sand the color coat. Just look it over for any flaws that you need to sand and respray. Clear goes on as soon as base is dry on your masking tape. It all happens pretty quick! Once I'm happy with the base, I clean paint gun, hit the restroom, have a cold drink, and smoke a cigarette. By then it's ready for clear. That usually takes 45 min-1 hour. I need to stop smoking.
 

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Discussion Starter #3
I didn't think so. Obvious to sand (very fine!) the clear coats. Should these be sanded between coats? Or just a final "color sand" to level the final surface before polish. I've color sanded (1500 / 2000 ) the clear on a 5 year old MBZ where the minor orange peel on the sides and c-pilars from the factory finish just got to bug me.

At least keep the cigarettes out of the spray booth!! Booom!

:D

Thanks
Robert
 

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Robert-
You'll not want to sand between clear coats. If you have runs or other goofs, just keep going as you can't really fix them until the clear is dry. 2-3 coats of clear, one pretty much right after the other. In other words, by the time you get all around the car and back to your starting point you're ready to go with the next coat. If you read the p-sheet for your clear it'll say 10 min. or so between coats.
Another thing is to look behind your spray pattern when you're spraying. It means you see what you've done instead of what you're going to do so you can adjust your speed and overlap as you go.
Runs and sags are high spots and as such can be blocked down flush with the rest of the surface. Not that big of a deal really.
Buy a cheap paint suit so lint, hair, etc. doesn't get in your clear. I found a black hair (from a friend who was in the booth watching) right on top of the fender about 2" back from the headlight when I painted my Spider. About 30 min. after I was done, one end was sticking out of the clear. I pulled it out with a pair of tweezers. The next day there was no trace of it. The stuff flows a tiny bit for several hours.
 

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Spray the color(base) coat on medium wet, meaning if it takes you three coats to get good coverage and hide the primer, you should be doing well. What you don't want is runs in the color coat. After I have good coverage, specially with metallics, I spray another coat or two over the whole car but not using back and forth overlapping patterns. I spray the last color coats on very dry, maybe a foot or two above the panels, just mysting the color and flakes on to get the flakes to stand up more uniform and develop a consistant color across all panels. The early color coats hide the surfacer, the last color coats are what will define your final color and sparkle.
 

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Discussion Starter #6
The old lacquers were semi transparent, so the color of the primer mattered (black under red was very different than white or yellow under red especially). SInce these two-part paints use a thinner color coat, are they more opaque, so that the underlying primer color doesn't matter so much?

Or should I use a tinted primer?

BTW - thanks all for so much help. It's been 20 years since I sprayed my Alfa, and then it was a lovely lacquer. Anti-Josephean, it was a color of many coats....

;)

Robert
 

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Don't worry about tinting your high build primer (the PPG Omni MP 243 I always use is grey, for example). 2-3 coats of color will do the job.
 
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