A Lesson My Car Taught Me

[Kenn S.]

One could hardly argue that paint quality from St. Louis was stellar. At a chapter meet last year we closely examined a 1975 convertible, and the paint expert no sooner got done telling us about common paint drips when we spotted a drip right smack in the middle of the driver'd door. The factory rubbed a bit and kicked it out as-is.

So I was aware of oddball paint issues with the 1980 I'm working on. I noted the lack of paint under the fender flares-common, typical.

But I just removed the passenger side door, and look at what I found (image). NO paint at all, and I'm sure these are factory panels (part number shows in one of the bonding strips and there is yellow crayon marking behind blower motor area).

I'm posting this because I'm floored, for one thing. But it's easy to see an over-restoration about to happen. Clearly the factory popped the unpainted doors on the car an whipped it down the line. To be a correct restoration, we'd need to approximate this process. While emotionally difficult to do, to be correct it's what you have to do. Moreover, it's this type of thing those paint judges are looking for.

For this car, judging isn't in its future (especially if I wedge in that crate LS3). But for my 1970...different story, unless I just can't do something so awful to that beautiful car.

[John H.]

Re: A Lesson My Car Taught Me

Clearly the factory popped the unpainted doors on the car an whipped it down the line. To be a correct restoration, we'd need to approximate this process.

Kenn -

That was the factory process from 1953-1981 at St. Louis - not one drop of paint went on the car until after the body entered the Paint Shop, fully assembled. Photo below shows very late C3 bodies leaving the Grind Booth on their way into the Paint Shop.


SeamSand.jpg

[Kenn S.]

Re: A Lesson My Car Taught Me

Amazing. And to think I never really noticed until I started ripping one part to this degree. Thanks, John.

[Russ S.]

Re: A Lesson My Car Taught Me

If it can't be seen till you tear it apart then it didn't really need paint there.

[Tom R.]

Re: A Lesson My Car Taught Me

That was the factory process from 1953-1981 at St. Louis - not one drop of paint went on the car until after the body entered the Paint Shop, fully assembled. Photo below shows very late C3 bodies leaving the Grind Booth on their way into the Paint Shop.

John

I had shared with Kenn in his other discussion post that I was replacing the reinforcement straps along the fender sides and the bumper bottom rear to rebuild it and support a Pace Car spoiler. All of which made me curious about at what point were the bumpers painted? The photo shows the bumpers not installed so they must have been painted separately and than installed once baked.

scan0034.jpg

Well I went back to an old folder I kept and curiously, retrieved this photo to answer my own question. Here we see no bumper, valence, etc. Same with rear bumper. Final body assembly must have occurred once body was married to chassis.

[Kenn S.]

Re: A Lesson My Car Taught Me

And having removed those covers with the bumper assemblies in place, I can tell you it's no picnic. Some contortionist must've put them on at the factory. For assembly I was thinking about bolting the bumpers after assembling the covers. It would appear you could do that, which would be contrary to the line photo. But if it worked out, it would be a lot easier to get those puppies back on.

As for not seeing, I think the point I was hoping to make was that it would be easy with the door off to say the heck with it and paint where the factory missed. I'm just now really learning about how these were put together, and for others in the same spot on the learning curve, the lesson would be to resist any temptation to "improve" things if judging is your goal. That you couldn't see this wasn't precisely true. I did. But I honestly thought it was dust/dirt, much like I have underside the rear fenders. I was surprised, to be sure.

[Duke W.]

Re: A Lesson My Car Taught Me

The soft bumper covers required a different paint mix that was much more flexible than conventional acrylic lacquer, so the bumpers covers would have been painted separately from the body then assembled with the other parts that made up the bumper assembly and bolted on after body drop.

It wasn't really any different that with earlier chrome bumpers. They were installed after body drop, too, but they had no paint.

Duke

[Rodney R.]

Re: A Lesson My Car Taught Me

I restored my 1980 two years ago and this post cleared up some of my unanswered questions. When I took the door panels off I came across the same thing you explained. It appeared maybe at some point the door skins were changed. I am the second owner and know they are the original doors. I had prepared the bumper covers off the car because of the flex additive.

[John H.]

Re: A Lesson My Car Taught Me

John

I had shared with Kenn in his other discussion post that I was replacing the reinforcement straps along the fender sides and the bumper bottom rear to rebuild it and support a Pace Car spoiler. All of which made me curious about at what point were the bumpers painted? The photo shows the bumpers not installed so they must have been painted separately and than installed once baked.

[ATTACH=CONFIG]54234[/ATTACH]

Well I went back to an old folder I kept and curiously, retrieved this photo to answer my own question. Here we see no bumper, valence, etc. Same with rear bumper. Final body assembly must have occurred once body was married to chassis.

Tom -

The RIM Urethane fascias required a totally different flex agent primer and paint chemistry than the body paint, with completely different bake schedules, and there was no room in the plant for a separate paint system for them - they were painted by the outside supplier that molded them (most likely Guide Division, in Rimir, Mexico).


Fascias.jpg

[Tom R.]

Re: A Lesson My Car Taught Me

Tom -

The RIM Urethane fascias required a totally different flex agent primer and paint chemistry than the body paint, with completely different bake schedules, and there was no room in the plant for a separate paint system for them - they were painted by the outside supplier that molded them (most likely Guide Division, in Rimir, Mexico).

I did a Google on RIM (reaction injection molding) Urethane fascias out of curiosity and came up with this 1984 technical paper from SAE.

An Integrated High Performance Bumper Concept Using Urethanehttp://papers.sae.org/840220/

I suspect this was the case as well in 1978. All of which means that in 1978 for the Pace Car and anniversary, once assembled, the plant had to paint the 25th paint schemes. As we discussed elsewhere, Corvette assembly had to commandeer other plant campus space to complete the anniversary schemes...paint and decals.