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Why So Many Coats of Clear?

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Old 06-12-2010, 03:40 PM
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Default Why So Many Coats of Clear?

I'm not understanding why people are using more than 3 coats of clear, which in most systems, over 2 is pushing it slightly. A lot of threads here and on all those tv shows "overhaulin", "street customs", etc say we used ppg and layed down 6 coats of clear. How does the clear not crack at that point? Unless you're laying 2 or 3 down, letting it dry, sanding it and spraying 2 or 3 more (that's what the painter at work suggested they might be doing). Spraying more than 3 coats back to back would be trouble. These paint companies have warranties for their paint, and when something goes wrong they come and inspect it with a gauge and if more than 2-3 coats were used then they'll say you're on your own because you didn't follow directions. So are they being sprayed back to back or let dry, sanded down flat and re-sprayed?
Old 06-12-2010, 03:49 PM
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When I do multiple layers like that, I do like you said, and lay down 3 or 4, let it cure, block it down and spray 3 or 4 more... You also have to realize how much clear is being removed during the sanding process. Sure, you may spray 6 coats, but you can easily remove 3 of those during the wet sanding.

Custom paint is a little different though, and ACTUALLY, what the deal is with paint thickness is not dealing with 2 or 3 coats. 2 or 3 coats is the "factory recommended" amount to achieve proper UV protection, NOT paint thickness quality limitations. Nowhere does it say that if you spray more than that that they wil not stand behind their product. It comes down to mil thickness. Most paint companies wont warranty anything over 12 mils thick. A factory paint job is about 3 mils (primer through clear) so you have room to do 2 more repaints before you need to look at stripping the paint off. 1 coat of clear is approx 1.5 to 2 mils, so if you spray 6 coats of clear you will be at 12 mils BEFORE sanding. I have 7 coats of clear on my car(I painted it myself - sprayed 4, blocked it down and then sprayed 3) and PPG has said that I am still within their warranty specifications.
Old 06-12-2010, 04:02 PM
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Cool thanks for the reply, I always wanted to know, but the painter I work under or anyone I knew never did that kind of work so couldn't tell me.
Old 06-12-2010, 04:30 PM
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Originally Posted by Marc3.4V6
Cool thanks for the reply, I always wanted to know, but the painter I work under or anyone I knew never did that kind of work so couldn't tell me.
No problem man! Glad I helped! Now I will say that the period of time they do a paint job on overhaulin is not the best by any means... its better to give the paint time to cure a little before buffing, but they cant do that under the time they have to work with.



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