Black BMW with paint problem

[Totoland Mach]

I'm reconditioning a Black 545i that has thousands of "pock marks" in the clear coat. I've tried wet sanding with 2000 grit, 3000 grit, compound with cutting pad...u-name-it and it's been tried. I've paint guaged the finish and it appears to be original, but don't want to take the clear to a dangerous level.

Here's some pics of wet sanding a trunk lid scratch and some examples of the paint condition that I am writing about:

Trunk scratch:



Sanded with 3000 grit on a Snap-On orbital air sander



Used a 7006 pad on the rotary and compound, followed by an 8006 pad and 83



After 83 and glaze



Here's a pic showing the clear pock marks: It's a little tough to get with inside lighting, but you can see those "dots"...they aren't white, just indentations



Another close up before I started the compounding. I've repaired the scratches, but am left with this poor finish



Any folks have suggestions? I've run out of ideas and the BMW dealer and I are pretty frustrated with this paint.

Totoland Mach

[repo]

Re: Black BMW with paint problem

How many mills have you already taken off?

[DocVoxel]

Re: Black BMW with paint problem

Possible hail damage?

[jfelbab]

Re: Black BMW with paint problem

Looks like pinholing. Unfortunately there is no easy fix for this.

[Totoland Mach]

Re: Black BMW with paint problem

Looks like pinholing. Unfortunately there is no easy fix for this.

That's exactly the description I would call this condition. As far as paint guaging, it measures up to OEM paint levels (5.4 -5.6) and the areas that I sanded went down to 5.2 - 5.3. If it was a car that wasn't going to be sold, I would take a more aggressive approach. Since the car still has remaining warranty, I'll probably inform the new owner and they can take it to the dealer for evaluation.

Toto

[gtijon]

Re: Black BMW with paint problem

Looks almost like silicone contamination causing fish eyes to me. Has the panel been resprayed at some point?

[Totoland Mach]

Re: Black BMW with paint problem

Looks almost like silicone contamination causing fish eyes to me. Has the panel been resprayed at some point?

I'd agree it's contamination of some sorts. I used a paint guage over the entire car and it's consistent with OEM paint. I suspect there was some contamination at the original paint booth.

Toto

[Tom Weed]

Re: Black BMW with paint problem

I have little spots or pitting on the hood and roof of my Grand Prix, it looks like it's in the clear coat, but it won't budge when I polish it. I'm pretty sure they aren't water spots, and not sure there's anything I can do about them or how they got there. I had the same problem on a white Honda Civic I detailed a few weeks ago, it has these same spots along with water spots. The water spots buffed out on the rotary with 84 on a polishing pad, but the little spots or pitting remained. I would love to know what that is and how they happen.


Tom

[jfelbab]

Re: Black BMW with paint problem

Pinholes are small microscopic gas bubbles trapped in the paint. The paint skins over and hardens trapping the tiny gas bubbles. Some causes of pinholing are poor mixing, poor filler and stopper, improper temperature and a few others.

I've seen these pinholes in quite a few cars over the years, mostly on repaints. OEM paint is typically high quality, properly mixed and the conditions are monitored more closely than in a repaint booth.

Pinholes cannot be buffed out. The only way to eliminate them is to sand down to the primer, spray a filler and resand, then respray.

While I've not seen this documented anywhere, I believe pinholes may lead to an early clear-coat failure.

[Tom Weed]

Re: Black BMW with paint problem

Well, I'm pretty sure on my car that they weren't there when the car was new. I will take some pics and some readings on my ETG on the spots and see what I get and report back.

Tom

[the other pc]

Re: Black BMW with paint problem

If they didn't come from the factory they occurred either mechanically (chipping) or chemically (etching). I think it's likely that droplets of some sort of aggressive contaminant sat on the finish for some period of time and etched their way in.

Whatever caused them, holes tend to be a lot deeper than swirls because whatever is causing them is concentrated in a very small area. Since you've already tried sanding and compounding they're probably too deep to remove without compromising the finish.

I guess you could try a small test spot and keep stepping up the cut until you either remove them or hit the maximum you're will to do. I wouldn't hold my breath though. At some point you just have to live with it or refinish it.


PC.

[Tom Weed]

Re: Black BMW with paint problem

Okay, I wiped down my hood and took some pics, those little "pits" are hard to capture... Disregard the stratches, I haven't polished it in a while, but the little specs that I've circled are what I was talking about. I don't know where I got them from and I'm pretty sure I can't remove them. The white honda civic had the same looking pits on the hood and roof also. I couldn't polish them out with 84 on the rotary and a polishing pad.

My readings on my ETG on my hood on average or 5.1 to 5.3 mils in this area.

Here's a couple of pics, best I could capture...

[gtijon]

Re: Black BMW with paint problem

If you've got pitting in your paint, and it's base over clear, IMO you have three options.

1) Get some rattle can clear, spray it on or paint it into the pits with a paintbrush, flat and buff.

2) Flat the pits out, then buff.

3) Repaint the bonnet.

The only way you're going to get rid of them is to fill them with more clear or remove the surrounding paint until the pits are gone. I'd be inclined to get the bonnet repainted if you're keeping it and it's really bothering you - it's not that big a job seeing as it looks pretty sound paint, so no repriming etc. will be required.

If you're selling it, I'd take option 1. It'll look a hell of a lot better, and yes, normal 1k clear does yellow over time, but the quantities of it that'll be left on the bonnet will be pretty minute, and it'll look good if you do it well.

[565Customz]

Re: Black BMW with paint problem

how did this turn out?

[Tom Weed]

Re: Black BMW with paint problem

565,
Well, I had Mike look at it at the Indy Roadshow class, it's definatley pitting. I've not done anything to it, other than just lightly polish it every so often and keep it waxed. You can really only tell it when you have it under bright lights and your looking for it. Just something I have to live with on my daily driver.

Tom