Thanks Paul! What a pal. (just kidding with the "I taught him that stuff")

 

But a human painter would see that his "spray applicator" wasn't laying the paint right and would change it before he screwed up 150 cars.

Tom

 

That would be the theory. There is a little bit of a time lapse from when the panel is painted until someone gets a good look at it. A fair number of panels can get painted. The panels travel two miles of conveyor space and spend 10 hours in the paint shop prior to being ready for assembly.

 

A robot is definitely more efficient for assembly line work, no doubt about it. The orange peel is mainly in the clear coat, and can easily be wet sanded out and buffed to a gloss. I prefer a custom paint job as opposed to factory, but then again, I myself am a bit biased. If I were to buy a new Corvette today, tomorrow I'd have it stripped down and would be spraying it House of Kolor Tangelo, but that's just me.

 

The following is from one of my previous posts on the orange peel subject:

The great paint jobs of years ago were done manually by people in the booth who could make changes to their spray guns "on the fly" when they spotted issues. Now with automation, everything is sprayed at the same settings. Someone down in Quality Control has to see the issue, make calls back to the paint shop before changes are made. By that time, who knows how many vehicle panels have been painted and if the defects are acceptable (orange peel) the panels go on down the line.

Humans have been being removed from inside the paint booths for many years now. One reason is to reduce cost and improve throughput, but the biggest reason is for health reasons. We customers demand so much from our paint finishes, that the paints/solvents being used today to meet these demands are extremely unhealthy for us humans. Some can even be deadly until they are cured. Robots don't get sick and have to stay home for days/weeks.

 

The Corvette clear is very hard but very, very thin. Wet sanding stands a very good chance of breaking through to the color coat. Orange peel is not necessarily in just the clear. It can be in the color coat which then gets compounded by the clear. You can have peaks and valleys in the color coat which become peaks and valleys in the clear. You can also have more OP in the clear on top of the color coat. The reason a wet sand leaves the car looking better is that you are smoothing and flattening the high spots in the clear. The risk you run is that you have broken through the clear and exposed the color coat to oxidation.

 

I am only speaking from motorcycles and cars that I have personally painted. I usually apply 3 coats of clear, then wet sand with 600, then apply 3 more coats of flow clear. I can't speak for how thick a Corvette's clear is, as I've never wet sanded a new Corvette. Nice to know that it's thin though, for future reference.

 

I sat and watched again, over the weekend, the "Ultimate Factories" show that was done on the Corvettes. I paid real close attention to the short segments about the paint shop. The Corvette basecoat color is being applied with dual head electrostatic guns. The last time I was in the BG paint shop, they were using these types of guns but were not using the electrostatic feature as they were afraid of the high voltage. Those guns at that time were made by ITW Ransburg, the company I used to work for. I do not know if the guns in the TV show are still the same ones or not, but they sure do look similar.

Anyway, the basecoat color is being applied with guns and the clearcoat is being applied with rotary atomization or what we refer to as bells. After watching the video (tv show) I am starting to believe that the orange peel we are all seeing is more than likely in the basecoat color. Guns are not as forgiving as bells. Guns can not produce the very fine atomization that a bell can delivery and also tend to more often than not produce "dry spray". Dry spray is one of the biggest contributions to orange peel as the paint is not wet enough to allow "flow out" on the surface. If the atomization air on the gun is turned down to provide a wetter finish, then atomization (droplet size) goes up and again, orange peel can be produced. With a bell, the bell cup has a very fine serrated edge to atomize the paint. To produce a wetter finish, the bell cup is slowed down. To produce a dryer finish, speed up the bell cup. You want no more bell speed than is necessary to produce acceptable atomization. Todays rotary atomizers operate at speeds from 20,000rpm up to 70,000rpm. The bell is just a much more versatile tool.

What we need to get some information on is what is the appearance of the color painted panels prior to the clearcoat being applied? As the conductive primer is also being applied with air atomized guns, there could also be orange peel after that process that is being telegraphed all the way through the clearcoat. Test panels need to be produced where only each process is applied and then the panels are examined. I know that I am not saying anything the guys at BG working in the paint shop don't already know, but I do think with a little deeper investigation, the orange peel issue could be resolved. Of course, this might require the investment by the plant to install bells for the basecoat color zone.

Just my thoughts and observations.

 

 

After having read your profile, I guess you have first hand knowledge on this subject! Thanks for speaking up. Hope I get to get in there and meet some of you guys real soon. Bet working together, we could really make an improvement.

 

Read his profile. He works in the BG Paint Shop.

 

Been wet sanding #2000, some #1500 To #2000, ..Factory side panels are rally sad for 50 grand...You can all go on and on,..robots, robots.. my blk '07 will look like it should..It will have a little, peel left, as don't want to look like a repaint...It will all match the hood and horz, panels are pretty good...my neighbors cobalt came fine...go figure..

 

On a recent visit to the NCM I looked for orange peel and guess what I found? ORANGE PEEL!!! EVERY car had it to varying degrees. The only ones where it wasn't obvious were the ones done as paint samples by paint companies. Here is a sample of what I found but by no means the worst. Note that it has "Special Build Code ZF-1 Show Car Priority".

Click on thumbnail.

 

You likely won't have any (or much) clearcoat left when you are done. If you think that your neighbors car with a factory paint job doesn't have orange peel I'd say that you need to look closer.

I'd also venture that the Cobalt doesn't have the complexity of painting SMC and RRIM body panels. As I recall the Cobalt still has metal body parts.

Lastly, cost has nothing to do with it. Savings in parts, labor, materials and design is what allows the Corvette to only cost $50,000. You will find orange peel on cars costing much, much more than the Corvette.

 

Trust me - you have it.

 

I'll have enough clear coat for me...Just a cut above looking vette, and 50 grand is a lot of money to me...prim panel, smc, If the top panels are nice ..do it correct .....

 

So, If the finish was color sanded very flat and it did cut the clear to the color and then a good painter put another coat of clear on, would that be a good practice?
Seems that a new clear coat finish would be much less of an issue than a new paint job. For my car the "Lemon" peel I am most concerned is just the doors, not the entire car

 

I would leave that answer to more of an expert on automotive painting but I would say yes, adding a subsequent clear coat would be good from a protection standpoint and most likely from an appearance standpoint.

 

The doors can be sanded and recleared without doing the whole car.

 

A Porsche Cayenne pulled up beside me today at a red light and his paint had considerable "orange peel"...more than my black 07! Funny thing is, I probably would have never noticed it if I hadn't seen the posts on here which introduced me to it.