PPG clear coat changed color/reflectance of silver met. paint

A couple of issues here and this is not an uncommon problem with SOME colors.
Here is how bad of a problem, Toyota has a letter out how to blend a door.
say you spotted a 4 inch scratch in center of door, spot base and first coat of clear you "spot the clear" covering only the new base, let it flash and only one coat of clear on door so it does not reflect light difference next to factory clear.
Biggest problem colors with this? Some finer silvers like VW, Mercedes, BMW., whits, and some pastels.
Why? its all light reflection, how thick is factory clear? 1 mil? one wet coat of universal depending could be 2 mils or more. (Depth)
Another risk is different clear on a repainted job lots of factors in a clear that could add to this problem.
Type of UV's used.
Amounts of UV's used.
Gardener rating on resins used.
Amount of coat applied on one panel verses the amount of clear on the adjacent panel.

Summery this can happen with any color BUT only certain colors will show it.
 
Mercedes silver it is. Doh. The amount/thickness etc of clear applied, while never something that could be determined exactly, I understand could be causing the issue seen (well that among all the other things you mentioned). The same painter did the original re-clearing and then re-clearing door test with the same clear coat and weather conditions.

The roof, sail panels, 1/4's, trunk lid (whole car originally had 3 clear coats applied) were lightly scuffed/sanded with 1000 grit, then re-cleared with 2 coats.

But when the same procedure was done on the driver door to see if it would change like the back half did, it did not. And that is where everyone is stumped.
 
But when the same procedure was done on the driver door to see if it would change like the back half did, it did not. And that is where everyone is stumped.
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With all do respect, sorry, I'm not buying it.
Unless the blend turned into the whole quarter being bases with a darker color the above statement is wrong.
Could on the re-clear of quarter it was screwed up and they had to next day wet-sand one part or two and clear more? some areas now are loaded up and sanded spots less coats.
Sorry but you weren't there? and only two things can cause this, base don't match or clear is loaded or different clear but different clear was ruled out when you said 2 coats on door did not change it, SO back to the quarter paint job!!! and the rest of the story!
 
Color was not touched on both 1/4's - only sanded and re-cleared with 2 coats along with the rest of the back half.

Then when done, after noticing the darker hue inside in low light, the driver door it was determined that it be sanded at the gap and sanded into the re-cleared 1/4 panel again too.... and that area together recleared to test... and the door did not change 'hue' and the 1/4 panel stayed the same.
 
I don't know anything about mixing ratios/reducers/resins or percentages etc of clears or paint.

But yes, what I saw and know process wise I am reporting on.
 
Years ago friend painted a 55 wagon in pieces. All at the same time. Tailgate hung from ceiling in same room. Sprayed at same time, tailgate was different shade than rest of car. Color was red. What caused it? He never figured it out. Ended up respraying it. You may never know. There are so many factors that could have caused it.
 
Bummer. I would never have anything painted separate from the car. I have seen that many times with detached doors or hoods ending up different. Angle and distance to part being sprayed, etc. One flow pattern on whole car best is what I have realized.

As for this... go figure. Going to re-attempt to duplicate back half clear on the door next week. See if it can be duplicated to door. May be more clear on door, less on 1/4....
 
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NextGen Classics said:
You will keep chasing your tail on this,adding mils of uneeded clear. It is easier and better in the long run to scuff/sand the whole car and reshoot it
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X2, especially with such a dramatic difference between the door and the quarter.

BTW, when given the chance, I always paint my cars disassembled, but with the panels oriented as they are on the car. I just paint them at the same time with the same gun settings.
 
Good call rdransman. Ideal.

And as for this mess, scuffing/sanding and reshooting the whole car in base then clear may be the only way out of this, but dang to ruin a whole car paint job over a small roof scratch just kills.

Plus wouldn't be disassembling the whole car this time to do that so sure gonna never be the same. Such a bummer.
 
What i learned from this thread is benifit of having 1 of the motion activated security cameras for building looking in or mounted in booth with tare-offs.
If painter's honestly telling it like it was, he'd be able to "go to the video tape".
8 channel nvr & a few 4mp or 8mp cams is under a grand self installed.
 
Might want to do some spray out panels where you do color then after it's dry tape it out so that you can do 8-10 coats of clear. Side benefit is that you may find out how many is on 1/4. I usually use metal panels so that it will look close to what will on the car.
 
madgoat said:
Good call rdransman. Ideal.

And as for this mess, scuffing/sanding and reshooting the whole car in base then clear may be the only way out of this, but dang to ruin a whole car paint job over a small roof scratch just kills.

Plus wouldn't be disassembling the whole car this time to do that so sure gonna never be the same. Such a bummer.
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I'm crying with you! I wouldn't disassemble either. You'll be OK in the long run, and the repaint will be a distant memory!
 
Barry said:
A couple of issues here and this is not an uncommon problem with SOME colors.
Here is how bad of a problem, Toyota has a letter out how to blend a door.
say you spotted a 4 inch scratch in center of door, spot base and first coat of clear you "spot the clear" covering only the new base, let it flash and only one coat of clear on door so it does not reflect light difference next to factory clear.
Biggest problem colors with this? Some finer silvers like VW, Mercedes, BMW., whits, and some pastels.
Why? its all light reflection, how thick is factory clear? 1 mil? one wet coat of universal depending could be 2 mils or more. (Depth)
Another risk is different clear on a repainted job lots of factors in a clear that could add to this problem.
Type of UV's used.
Amounts of UV's used.
Gardener rating on resins used.
Amount of coat applied on one panel verses the amount of clear on the adjacent panel.

Summery this can happen with any color BUT only certain colors will show it.
Click to expand...

Good info Barry, did not know this. :) Never encountered it though in my career.

Madgoat issue though does not make sense to me if it happened as they are telling you. Unless you witnessed the entire repaint (that would make you a customer from Hell in my opinion :) ) then you really don't know what happened. I sprayed PPG for many years and one issue that I did notice is something I call "Flop". Flop is the orientation of the metallic in the base and how it appears in the light to your eye. Crappy definition but maybe Barry can clarify it. When you repaired an area and blended the "flop" would sometimes be going the other way which would make the color appear off. All metallics have angles when viewed where they appear lighter and darker. That could be what is going on here. But that would imply it was based. If it was based (most common explanation by far) then all bets are off. Certainly appears that way to me.

Used to have to add a flop adjuster when mixing DBC.
 
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I saw this thread this morning and didn't have time to write a post. So after thinking about it today at work and talking with another painter I think it's possible that a tiny amount of overspray did this. If it was any other color but silver I wouldn't have brought up this idea. Since the painter was spotting in the roof the overspray had to be flowing across the quarters in a down draft booth. Most colors would show lighter if this happened however silver is the odd duck in that sometimes it just flops. Kind of reminds me of the color change paints that became popular twenty some years ago. You could reduce that stuff down 1000 to one and spray one light coat and still see the effect. Same idea with a tiny amount of overspray. It wouldn't take much. ~BOB
 
What I can't say is how much was taped off on the car when the base was painted on the small roof area that needed color feathered in --- but I doubt they didn't cover and mask most of the car.... but to think that downdraft or overspray would uniformly get on both quarters evenly to cause this is somewhat hard to fathom. But I guess possible to some degree.

The touched up area with base was really small on the front corner of the roof.

The entire back half is uniformly an issue being darker in shade, and brighter in sunlight in all areas - but in the sun not so dramatic unless you look for it. But in the shade is the major disparity that bugs and says to me that something is wrong.

Now why that could not be duplicated on the door is what really is the issue now. Sucks the back half reacted how it did. Just trying to make the best of it.
 
In the sun, the door to 1/4 color is still off. Just not as dramatic when indoors. And the issue actually reverses in bright light versus shade.

Indoors the back half looks darker. Outside the 1/4 looks slightly brighter/whiter as shown below.
20190503_152818 (1).jpg
 
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