Mysterious Streaks Under Clear Coat

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PostPosted: Mon Dec 17, 2018 8:24 pm
Hi I am a newbie here, but have been a devoted car guy and have done my own detailing and touch ups for many years. I have a paint issue I cannot explain or understand.. I have a repainted 1987 MB 560SL which I bought a couple of years ago.. It is an older pro-quality repaint, in original MB diamond blue metallic.. The car was blemish free until last week when I uncovered it and found an odd streak on the hood which is under the clear coat. I was baffled.

The two photos below are the same streak from different views. It appears as hazy white from certain angles, and looks somewhat brownish from other angles. This blemish appears to be well below the clear coat, which shows no sign of surface blemish or texture above this streaked area. The car has been clean, waxed and maintained--either garaged or under high quality weatherproof cover.. So, what would cause this sort of streak to suddenly appear on a well maintained car with a solid intact clear coat? (disregard other reflections on the car in the photos)
IMG_0501.jpg
streak view 2
IMG_0500.jpg
streak view 1



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PostPosted: Tue Dec 18, 2018 11:49 am
this is a hard call, what I can say is it looks like the clear is starting to delaminate from the color possibly accelerated by the car cover. car covers are great, I use one on my street rod when it sets in the garage all winter. its dry and the thin cover just keeps the dust off. but a cover used outside in the elements such as rain, cold and heat can cause many problems. especially if the cover has any plastic as a water proofer. more info would help such as the type of cover and the climate where you live. lets see what others have to say.
Jay D.
they say my name is Jay

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PostPosted: Tue Dec 18, 2018 10:10 pm
I think there is a basic "assumption" that car clear coats are totally impermeable and it just isn't so. Those tiny unseen almost microscopic fish eyes, solvent pops, etc. in many cases can go directly down to the base metal. Over time even more flaws develop because the heating/cooling cycling of the surfaces. This can be compounded by exterior grade car covers as they are usually "breathable." That means they also have a pore structure which is supposed to let moisture come and go.
So how fast do they breath???? It was early summer and we had a few days of hard rain and I had to keep my car outside under one of those covers.....the rain breaks on a hot sunny morning. I reached my hand up under one edge of the cover and it felt like a steam sauna in there. When I pulled the cover off my car was literally steaming..... I'm thinking steaming your paint.....not such a good idea. I only use soft cotton covers now and then INSIDE my buildings....
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PostPosted: Wed Dec 19, 2018 12:06 am
Glad that sound advice was forth coming because my mind was starting to make stuff up as to why?
Is it just me? For a brief moment I was hoping for, relax, it'll clear in a day or two?

Now all I want is to pick at it a bit? Is that normal?
I can see myself giving it a good reason to be a blemish? Start small, say an eraser and work up to a week of work? Lol.
I'm a tarp guy myself. I could learn to live with it? Still a beautiful ride.
But it still ruins a moment when you discover it's there.

So...what's the plan? Live with it or get er done?



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PostPosted: Wed Dec 19, 2018 10:24 am
badsix wrote:this is a hard call, what I can say is it looks like the clear is starting to delaminate from the color possibly accelerated by the car cover. car covers are great, I use one on my street rod when it sets in the garage all winter. its dry and the thin cover just keeps the dust off. but a cover used outside in the elements such as rain, cold and heat can cause many problems. especially if the cover has any plastic as a water proofer. more info would help such as the type of cover and the climate where you live. lets see what others have to say.
Jay D.


:goodpost:

DarrelK wrote:I think there is a basic "assumption" that car clear coats are totally impermeable and it just isn't so. Those tiny unseen almost microscopic fish eyes, solvent pops, etc. in many cases can go directly down to the base metal. Over time even more flaws develop because the heating/cooling cycling of the surfaces. This can be compounded by exterior grade car covers as they are usually "breathable." That means they also have a pore structure which is supposed to let moisture come and go.
So how fast do they breath???? It was early summer and we had a few days of hard rain and I had to keep my car outside under one of those covers.....the rain breaks on a hot sunny morning. I reached my hand up under one edge of the cover and it felt like a steam sauna in there. When I pulled the cover off my car was literally steaming..... I'm thinking steaming your paint.....not such a good idea. I only use soft cotton covers now and then INSIDE my buildings....


:goodpost: :goodpost:
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PostPosted: Wed Dec 19, 2018 6:51 pm
I appreciate the responses... The car cover is a new one, so that is the variable.. I have parked the car outside previously with a cover, but it was a thinner loose fitting synthetic one-ply cover. I never had an issue with it..

The new cover is described as "a robust 5-layer fabric to provide comprehensive protection against all elements (including rain, light hail, and snow) The non-woven, layered construction is specifically designed for moderate to high weather conditions and outdoor use"

In other words, there is a chance that the new cover has created a capsule over the car which is causing some reaction with the paint.. It just seems strange that this car has been in hot and cold climates... snow, rain and hot L.A. days, and never had an issue before now.



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PostPosted: Wed Dec 19, 2018 7:08 pm
clear coats can last a long time, but when THAT day comes it could be 1 year or 20 years. I bought a new 914 Porsche back in the 70s and the clear delaminated in less than 2 years
Jay D.
they say my name is Jay

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