Explain clear coat failure to me. (Pictures inside)

F

Frito Bandito

New member
My little sisters 2003 Cavalier is in the early stages of clear coat failure. While I was inspecting the damage today it occurred to me that I don't really understand what causes it. What are some of the causes? Environment? Bad paint job from the factory? What exactly is happening when clear coat begins to fail? I only noticed it on the roof maybe 6 weeks ago while I was polishing the car with my PC and OP. Sucks since most of the car turned out pretty nice.



Here is a picture of the failure on the roof:

IMG_0775.jpg




Trunk lid after I hit half of it with OP:

IMG_0635.jpg




The hood turned out particularly nice:

IMG_0730.jpg
 
I would imagine that the molecular bond of the clear coat is starting to break down or separate when failure is evident? I think it happens from a variety of factors, including the ones you listed.
 
I wish it was still under warranty but the car is 4 years old and has 60,000 miles on it. Way beyond 3 years/36,000 miles unfortunately.
 
Never seen that on a Cavalier, have seen many working at a dealership. Is it possible that it was wetsanded or heavy cut in the past? Thinning the clear.
 
It's possible but I don't think it's every been wetsanded or machine polished except when I polished it with OP. The car was bought new and I never saw any buffer trails or sanding marks.........
 
Great Thread.. I spent over 6 hrs on my paint today, and I was able to remove all the damage except a few scratches which IVe managed to blunt the edges on, but they wouldnt come out.. And, I dont want to take and sand paper or the rotary to it as I dont have alot of faith that theyll come out before I remove over half the clear, which is more than is recommended.



At that point it occurred to me, since only 25% of the clear is supposed to be the max that is removeable, which is something like only .3 to .5 mils, Im surprised we dont read an awful lot more about tales of failing Clear. With the working window in the clear that we have being so small, ie, just .3 to .5 mils, thats not much room for error.. Maybe two attacks with the rotary and a moderate cut compound is all it can take. So, realizing how fragile it is, how come we dont read of something like a case a day of clearcoat failure? Surely, judging from all the Autopians out there, there are plenty of us attacking our paint in an effort to achieve sublime perfection on a regular basis.. So, where are all the failures of the Clear?
 
Nah, I think that it can take more than just two aggressive polishing sessions. I don't have exact numbers, but the average paint should be able to be polished at least 2-3 times with aggressive polishes (though after the first, it shouldn't be needed anymore), and probably another 3-4 light polishings.
 
mikebai1990 said:
Nah, I think that it can take more than just two aggressive polishing sessions. I don't have exact numbers, but the average paint should be able to be polished at least 2-3 times with aggressive polishes (though after the first, it shouldn't be needed anymore), and probably another 3-4 light polishings.
Click to expand...





Hmm.. thats some supposition you made there.. You think that in say, a car's 10 year life, its only going to have one encounter with road gravel, or careless trucks tossing their loads in the air, or asphalt repair, or careless carwashing, or mistakes, etc, etc? If you only have one single opportunity for scratches in your clearcoat over a 10 year period, my hat's off to you!!
 
Well.. I said 2-3 aggressive polishings... I think that's reasonable. Marring that's caused by careless carwashing (by autopian standards) is usually correctable by light polishing. Somebody like DaveKG and other detailers with the paint thickness gauges should be able to give a more definite answer. I'm just saying that normal OEM car paint will most definitely be able to last more than two passes on a rotary with a medium cut compound. That's why we don't see CC failure on these cars.



edit: paul e, I found a thread that talks about what pad/compound removes how much paint. Just for reference, .3-.5 mils=7.62-12.7 microns.



RAG said:
I wanted to share my test results with others on this board, and because it takes so long to conduct the tests, I was also hoping that other Autopians with an ETG would peform their own similar tests.

THE TEST: Measure how much clear is removed using various compounds, polishes, and pads with the rotary. With each compound and pad combination I polished a 2' x 2' area 5 times (each time I used 4 pasess and each pass overlapped the previous by 50%); the rotary was set at 1500 rpms and I applied medium pressure (about 5-7 lbs ) to the rotary (since I only polished horizontal surfaces like the hood, the weight of the buffer also added pressure). I made sure to let the paint cool in between each polishing.

Because total film build on most vehicles varies significantly throughout each panel, I made sure to consistenly measure on the exact same point (usually using a small rock chip for reference).

All measurements are in Microns...typical factory clear is approximately 40 microns thick.

Because the amount of paint removed for many of the combinations was so small, I think the test would prove much more accurate if I were to polish 10 times.

RESULTS:

1) Green P2 with SSR 3 removed approximately 2 microns

2) Green P2 with new (blue) OHC removed approximately 1.5 microns

3) Green P2 with HTEC+OC (50/50) removed approximately 2 microns

(tests 1-3 were conducted on my landcruiser whereas the remaining tests were perfomred on the hood of a black Jetta).

4) Yellow P2 pad with PO85RE5 removed approximately 1 microns (but I had a difficult time taking a consistent measurement in this spot for some reason...so I'd like to redo this test)...though as is, this tells me cutting pad without compound does not remove much clear.

5) Yellow twisted wool pad from CMA with PO85RE5 removed approximately 1 microns (I wash shocked so little clear came off)

6) Black Edge twisted two (two-sided) with PO85RE5 removed approximately 1.5 microns(again, shocked).

Black Edge wool with OP removed approximately 2.5 microns

7) Black Edge wool with HTEC/OC removed 7 microns of paint (combination of wool and compound seemed to triple the aggressivemeness).

8) Orange CCS with HTEC/OC removed approximately 2 microns of paint

9) Orange CCS with PO85RE5 removed approximately 1 microns
Click to expand...
 
mikebai1990 said:
Well.. I said 2-3 aggressive polishings... I think that's reasonable. Marring that's caused by careless carwashing (by autopian standards) is usually correctable by light polishing. Somebody like DaveKG and other detailers with the paint thickness gauges should be able to give a more definite answer. I'm just saying that normal OEM car paint will most definitely be able to last more than two passes on a rotary with a medium cut compound. That's why we don't see CC failure on these cars.



edit: paul e, I found a thread that talks about what pad/compound removes how much paint. Just for reference, .3-.5 mils=7.62-12.7 microns.
Click to expand...



Thats great stuff. I agree that 2 to 3 aggressive polishings or compoundings is about all Id expect also. But that just doenst seem like very much. I still think that we have a very small working window and margin of error. And if you use wool, which he says removes 7 microns, well that would only allow about 1 aggressive compounding!! Really small window of opportunity.. Now, lets assume that there are alot of old timer, single stage paint guys out there, who only know Rotaries and Wool with aggressive compounds. Given that theres a learning curve to working with clear coat paints, Im just saying Im real surprised we dont hear an awful lot more about failed clearcoat related errors emanating from too agressive paint correction.



BTW, one good turn deserves anothers, so heres my contribution to the paint removal discussion, brought to you by Meguiars, and, its given in Mils! :) : How much paint are you removing. - Car Care Forums: Meguiar's Online Archive



BTW, in his example which includes some wet sanding, he wound up removing .3 mils in a single paint correction. Now, if he sells that car, and the new guy drives it awhile, and winds up putting some scratches in that area, he basically cant correct it! But, he wont know it.. Hence, Id expect him to become one of the clearcoat failure guys Id expect to be reading help-threads from here on Autopia. IM just shocked we dont see alot more of it. Enjoy the link...
 
Good to see some conversation on the matter! To be honest I think a lot of people overestimate how much paint they are removing and underestimate the durability of their cars finish. In the thread you linked to Superior Shine indicates that after using Megs #83 with a PC at speed 6 there was no change in paint thickness. People often consider #83 to be pretty aggressive stuff........



David Fermani (who's opinion I respect quite a bit) has said a time or two that he's had customers that brought their cars to him 3 times a year for 5 years and each time he used a wool pad to buff the car out with no ill effect.......something else to consider.



I'm still pissed about the paint on my little sister's car failing already. I could have sworn I read on here that someone once wetsanded some clear coat failure then used rattle can clear........hmmmmm...........
 
Really? Hmmm. I happen to own a couple of cans of clearcoat, and I have used it on a couple of test strips ov plastic over which Ive sprayed some base color.. The spray on clear wasnt bad really. If you can eliminate any foaming or airbubbles upon application, which practice will help with re distance, etc, it might work. And you can layer it.. And you can knock it down with polish and make it look good.. But I have no idea how long it would last.. I guess if I made my factory clearcoat fail, before I went to the body shop for a professional refinish of the clear, I might try this home made approach myself.
 
Yeah, I have some duplicolor rattle can clear I've used to paint trim. It isn't bad stuff but it's old school lacquer based clear so I don't think durability would be up to par with modern clear coat. You're right about being able to layer it, there is no re-applying window with lacquer paint so you could add more whenever you want. Last time I used it on a trim piece I ended up with some orange peel. I applied the clear pretty heave so I wetsanded it then buffed the sanding marks out and it looked great. It may only slow the failure down for a few months but I have nothing to lose at this point. If I do it next weekend I will be sure to post pictures!
 
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