Interesting marks in paint.....

[Mike Phillips]

Re: Interesting marks in paint.....

1981 Porsche 928 - single stage Mocha Brown, original paint with just over 100,000 miles

Found it...

First use of my new D/A on a Porsche 928




Cool

[Murr1525]

Re: Interesting marks in paint.....

Hmm.. add another thing to check for when car buying... liner mat under the hood.

[Michael Stoops]

Re: Interesting marks in paint.....

Regarding the possibility of this being heat related: Forum member MaximusZTS has the exact same marks on the hood of his Ford Focus, and interestingly enough you can actually detect the pattern of the cross bracing on the underside of the hood when looking at these marks in the paint. His hood does not have a liner matt on the inside, so the only heat barrier seems to be the cross bracing. Sure enough, the outer surface of the hood directly opposite the bracing has none of this issue, while the rest of the hood does.

Just throwing that out there.

[hacker-pschorr]

Re: Interesting marks in paint.....

My favorite Porsche, and the hot rod of the Porsche marque. The only Porsche we would ever consider buying in fact since it has the V8

Let me know once you find one. Mine is pushing out over 400hp & three others in Green Bay are close to or over 600hp.

[Mike Phillips]

Re: Interesting marks in paint.....

Right fender, and the B-pillar between the rear quarter window and passenger glass.

That rules out the theory of impact defects and isolates the problem to paint failure. Not much you can do about if this is the case except repaint.

1981 Porsche 928 - single stage Mocha Brown, original paint with just over 100,000 miles

My favorite Porsche, and the hot rod of the Porsche marque. The only Porsche we would ever consider buying in fact since it has the V8

From Wikipedia,




[quote=hacker-pschorr;213281]
If I could afford a real one, I wouldn't be detailing my own cars...
quote]

[hacker-pschorr]

Re: Interesting marks in paint.....

Are these isolated to the front of the car?

Or all over the paint?

Right fender, and the B-pillar between the rear quarter window and passenger glass.

Are these on the Cobra in your Avatar?

1981 Porsche 928 - single stage Mocha Brown, original paint with just over 100,000 miles

Aluminum? Real or Replica?

If I could afford a real one, I wouldn't be detailing my own cars...

This car has been in Chicago / Wisconsin since at least the late 80's & has never seen winter.

I'm using this car to lean how to use the G110. I've always been able to bring back a good shine every spring, with the D/A I have been able to really clean up the paint (see original thread linked in the first post).
My G110 died last night, so I'm on hold until a replacement gets here.

[Jokeman]

Re: Interesting marks in paint.....

If anyone has those marks in their clear, take a look at them under a 10x lens. You should be able to see if there was an impact point in the center of the crack. Im torn as to if those are from sand storms or heat. My friends wife has the same marks on her hood. We dont have desert sand storms around here but during the winter they do lay a LOT of sand on the roads. Chips are all too common around here.

[Setec Astronomy]

Re: Interesting marks in paint.....

Oh, I believe you Mike, that your marks are caused by desert sandstorms. As PorscheGuy noted, perhaps yours are cracks in the clear from those impacts, where the OP's, mine, and 2hotford's may be thermal stress cracks...similar appearance but different mechanism?

[Mike Phillips]

Re: Interesting marks in paint.....

We just took a guess at to what the real problem is, don't really know for sure. We do know that our Pilot has these and they're only on the front of the car, so it could be heat related but how hot can a Honda quality car get?

We'll inspect closer and try to capture some pictures, maybe collectively we can determine what is causing this. For what it's worth, sometimes when we're driving around out here in the desert because it's very windy you'll drive through a sand storm and it sounds like your car is being sand blasted.

Since the cracks in our Pilot are in the front and that's what takes the brunt of the impact with airborne particles, that is what influenced our guess.

Frustrating to say the least.

[Tim Lingor]

Re: Interesting marks in paint.....

Hey,

I have seen those cracks on many vehicles, especially on the hoods of trucks that pull heavy loads. From my experience these are caused partially by high heat, again, which is common with vehicles that pull heavy loads.

There is probably other factors that cause these as well, but either way, they are annoying!


Tim

[Setec Astronomy]

Re: Interesting marks in paint.....

Mike, I'm kind of shocked that you have this kind of paint failure on your Honda; in regards to the location on the car, my recollection from my cars that have had this, it was more pronounced on the hood, so I'd say it's more heat-related. Those cars were never driven in the desert..and back in those days the shapes didn't really result in any particle impact on the hood (vertical grilles, horizontal hoods). One of the cars that had it bad had an FRP hood, but that was also a repaint, I think (I wasn't the original owner).

EDIT: Here's a DuPont paint defect page which talks about cracking http://www.performancecoatings.dupon.../cracking.html Note that they mention the "three-pointed star" shape. That page is really talking about fresh applications, rather than aged paint.

I looked up laquer checking and what I found didn't look at all like the pics here--my apologies to Mike; I've had at least 2 cars with marks similar to what's in the pictures in this thread, and was led to believe that was known as "laquer-checking".

[PorscheGuy997]

Re: Interesting marks in paint.....

I don't know. To me, it seems like this is a heat related issue. Our other Sable has these cracks just on the hood - mostly near the center.



As Mike mentioned, it could also be from contact with a particle. Then, due to heat and stress, it turns into a crack. Maybe...

Are you sure this is the original paint on the Porsche? It should be a single stage. When a clear cracks, the cracks are a white color.

[Mike Phillips]

Re: Interesting marks in paint.....

These are cracks in the paint.

Are these isolated to the front of the car?

Or all over the paint?

This is not what lacquer checking or lacquer cracking looks like, it does look kind of like this but only larger lines or cracks.

Our 04 Pilot has these on the hood and front fender and our guess it's from impact with sand/dirt/rocks from driving in the desert and on the I-15 between Irvine and Apple Valley.

Nothing you can do to fix them except to repaint the affected areas because the are throughout the film build of the paint. Cleaning or abrading them will just remove good paint and expose a deeper portion of the crack.

Are these on the Cobra in your Avatar?

Aluminum? Real or Replica?

[thecarguy]

Re: Interesting marks in paint.....

I agree, that is paint checking , commonly found with laquer paint . It may well be original , but over time laquer paint can check like that . The only way to fix that is to remove it completely down to bare metal . Polishing will only fill those " checks " with product and make them more pronounced .

Cory

[hacker-pschorr]

Re: Interesting marks in paint.....

That's laquer-checking, or something like it. Age, shrinkage from fillers under it or improper application--whichever it is, you can't fix that.

This is the original 1981 paint, single stage from Porsche.

This is a good car to practice with the D/A since unless I start stripping the paing off, I cannot make it worse
I'm hoping to repaint this winter.