Color Sanding / Paint Question, Looking for experienced advice... Options

[aggiezig]

Howdy 914world, looking for some feedback and advice.

I painted my car myself using PPG Concept single stage urethane in Mexico Blue (code 336). This paint was not cheap stuff, but I made sure to put 3-4 wet coats on everything so I'd have plenty of margin to come back after and flatten the peel. I was also under the impression that the color I chose was a solid color, not metallic or pearl. However, I did notice when spraying that there appears to be a very small amount of sparkle in the pigment, which is extremely noticeable if you screw up and paint a run.

When I put the last coat of color on my doors, I did exactly that and screwed up with a big run. Frankly, I was rushing and my brain was working a half step ahead of my hands. Anyways, I thought I might be able to sand the run out later as I've seen many times on other projects and YouTube videos.

Here is a picture of the run:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1549442246.1.jpg)

Long story short, I've run into some issues when wet sanding and buffing out my paint job. It seems I've sanded through the top layer of color in a couple of places. I'm not new to paint correction but maybe I have been misinformed all of this time. I thought the point of spraying many coats of color was to leave a safe amount of paint to sand off afterward when removing orange peel. Is this bad logic?

For what it's worth, I'm sanding using 2000 grit paper (1500 in some places, if needed) and able to correct sanding marks with LCC yellow pad on a long throw DA. I thought I'd need my rotary but the sanding marks are coming out easily with Menzerna Heavy Cut 400 on the DA.

However, it's clear that I've sanded through the top layer of paint and that the layer underneath does not match. There's also a darker ring of pigment around the transition between the layers.

Here is a picture of the door. The light spot, to the bottom right of the camera flash, is where I've gone through the top layer.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1549442247.2.jpg)

I've also rubbed through the top layer on an apparent high spot in my front hood. Here is a picture of that. You can imagine how happy I was with myself with I noticed what was going on.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1549442247.3.jpg)

I haven't had issues anywhere else on the car, but it's clear I'm going to have to have these two pieces re-sprayed. I'd do it myself but no longer have access to my "spray booth" and pretty sure the VOC paint I used is considered contraband in California.

My question is - what exactly is going on here. Am I sanding way too much off? Is there a color match problem? Is my paint actually not a solid color? I want to learn from my mistakes so I don't continue to make them on this very time consuming and expensive paint job.

Thanks

[AHudson]

First of all, you're a brave and talented man to be doing that job. And the Mexico Blue is just superb. Great choice!

I had that exact thing happen on a guitar we were building where the 'polish stage' sent us right through to previous layers. It was a sad day, following 8-10 coats of color to have this happen.

Mepstein's point about the solid color rising may be true. (I can't debate nor confirm) In my case, I had to sand back down to and recoat. Of course a guitar is more manageable and I feel bad if that's where you have to go to finish out that car.

Hopefully someone here will have more encouraging advice. Just keep the goal in mind; its going to turn out incredible.