Clear Coat Failure or Chemical

[Thomkirby]

Clear Coat Failure or Chemical



I was recently asked to look at a paint problem for a potential customer. They showed me the car but could not tell me any clues as to why this rear trunk top surface looked so bad. They asked if I could do anything as their co-worker said I might be able to correct their car.

Photo-1





Since I was running an errand at their business I took a look but had to schedule a time to return. I first reached out the Spikey Mike as I knew he did painting plus detailing and he might have a hunch. I returned with my paint thickness gauge and a selection of Griot's Garage BOSS creams. Based upon my earlier trip and Spikey Mike's comments I was doubtful that the paint was even worthy of paint correction (needing a new paint job).

I took the time to measure the bad and good sections and to my surprise the bad section was thicker than the good sides? That told me that the clear coat was still present or at least something was still on that trunk lid. I inspected the drip channels below the trunk (Mike's tip) and those were normal (very little signs of failure nor chemical drips). So something had to be placed on the trunk to destroy the clear layer.

Next I grabbed out the GG Perfecting Cream (Yellow) and a white cotton terry towel. I place a small amount on the terry towel and hand buffed to see if the panel would return clear or paint color (red). It was clean! That meant to my limited experience that what was on the surface still held the clear coat layer. If it was gone then I should have return the base color, so things were getting interesting.

Next I stepped up and used the GG Correcting Cream (Orange) with the same white towel. Still making some improvement but still clean towel.

Next I grabbed the GG Fast Correcting Cream (White) with the towel and rubbed hard. Still clean but it was taking off the outer layer and giving me a smoother feel.








I did not have anything more aggressive but dug into my kit and pulled out my KXK RID STICKS with a 2500-grit sandpaper. I used my water solution and did a light sanding to see if the slurry was white or colored. This was same as others and showed that the surface still had clear coat. Yet my problem is that I only had a small sample of sand paper and did not want to work in sanding the trunk in the parking lot! Yes, the owner had luckily parked in the shade and it was a pleasant afternoon temp of 80-degrees.

So what started out in my assumption of clear coat failure was in fact something chemical in nature (still an unknown).

Thankfully I brought along my new FLEX CBEAST and my orange pads and yellow from Griot's line. With nothing to lose, I grabbed the Fast Correcting Cream and Orange pad. Results in the first section pass were encouraging and that outer layer was abraded and starting to show the under lying metallic ruby color. I continued this process over the entire trunk lid. I switch over and did the same thing again this time dropping down to the Correcting Cream. I switched pads to a yellow polishing pad and finishing out with the GG Perfecting Cream.

Did this remove the defects in the paint? Client was impressed and the surface took on a completely newer look which was acceptable. I did not have anything more agressive in the pads with me but doubted that it would have mattered anyway. I suspect this was a chemically caused blistering of the clear coat much like bug or bird droppings etching into the sub-layer.

Anyway perfection is in the eye of the beholder and even in the case a 50% improvement was a win!

I give thanks to Mike Phillips for his constant teaching and preaching of test spots and the least aggressive approach. From him I have learned and will continue to learn, so tune in or watch the re-runs from his Thursday Live Detailing classes.



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Close up




PS; I also had the chance to use the Blackfire One Step to correct another section of the car due to paint transfer in the number area. It was easy and was a quick one-step buff and protected and DONE.

[Rsurfer]

Did you take any pictures?

[Thomkirby]

Yes. Just now pushed up.


Sent from my iPhone using Tapatalk

[Mike Hoekstra]

Looks great Kirby!

[Hirohito]

Its unknown in detailing but not in painting.

It's called gloss dye back, it generally happens after a repaint,


See the car is prepped and sanded taped up etc.

The base coat is sprayed and is supposed to have a flash time say 10mins for example but the painter is in a rush and decides to clear the panel before its dry.

Now some painters have a problem with paint imperfections and add fisheye eliminatior drops to their clear as well..


So basically this can be caused by 2 problems

One being the solvents from the basecoat drying escapes through the clear and leaves a haze that can be buffed off,

Two fisheye eliminatior if they put to much does very similar and can be buffed out as well.



Also cheap clear shrinks again, wet sanded an polished easily.

[Thomkirby]

Thanks for adding to the discussion! Unfortunately the iPhone photos do not give the best up close details that appear to our vision.

Although the owner states this happened sometime during the past year they never had the car near a body shop. Which is strange to me as I examine the right side after doing the polish. I can see what appears as a paint line where perhaps it is a bit thicker or a layer. Paint still has imbedded defects below the surface and with side lighting it looks to be swirls but those could have been a poor sanding of the color coat?

I do think you might be on the path of the problem but can these painting errors take time to manifest them months after the repaint?

So the mystery still eludes me but glad the process improved the appearance.

[Mike Phillips]

Just to chime in,

Hope you don't mind but I downloaded your pictures, rotated a couple of them and then resized and uploaded to your gallery here,

Thomkirby Gallery - AutogeekOnline Gallery


This enabled me to insert the photos into your original post so "I think" they now look correct?

[Mike Phillips]

It's called gloss dye back, it generally happens after a repaint,

I went to Skynet and typed in,

gloss dye back

And the first search result was a discussion on a forum for the SPI or Southern Polyrethans Inc paint manufacturer. To be honest, I've never heard of this brand of automotive paint.


Dye back


Here's the question,

I hope this is the right spot to ask this question. I hear alot of people mentioning dye back, what is this? And why does it happen? A pic would be great if anyone has one. Thanks for answering my newb questions I appreciate it.

Here's a staff member's answer. I've taken the liberty to format it a tick to make it easier to read.

Great question!

Of course the answer really depends on the product and brand.

A: Some clears do not like being reduced and that can cause die-back.

B: SPI does not care about reducer as long as a good grade, low grades can and will kill the clear.

C: Some clears can cause their own die-back if flash times are not long enough because of the low amount of solids. Not the SPI.


SPI clears can die-back from the following:

1. Abuse of polar accelerator.
2. Using a crap reducer.
3. Baking to hot or to long.
4. Leaving the booth fan running to long.

Now the above should give you a general idea to why and the differences in clears.

Now the truth, of all the calls I get for die-back, it is 99% of the time, from the base coat solvents.

So according to Barry, from his experience, the major culprit in Dye Back are the solvents used to reduced the basecoat or the color coat.


There you go...

[Mike Phillips]

I was recently asked to look at a paint problem for a potential customer.

They showed me the car but could not tell me any clues as to why this rear trunk top surface looked so bad.

Photo-1

Maybe you did this already?

I would have asked them,

Did you buy the car new? If so, did you get the trunk lid repainted?


If they say they bought the car used? Then ask them if the previous owner shared any collision work that had been done?


There's a ROOT CAUSE for one panel out of the entire car to fade like shown in the picture above and my guess is the panel was re-painted and then neglected. A simple quality buff and seal after the paint cured would have and could have probably refined the final cured paint and sealed and protected it from further degradation.


Most people don't take care of their cars be they new or used.

[Mike Phillips]

Also...


Anytime any of us are looking at some kind of paint defect and it's ONLY on a horizontal surface, that's a huge indicator of what the root cause could be.