1984 Chevrolet Camaro Z28 - Primed & Ready
Setting the Stage for Paint With Bodywork & Primer
From the March, 2007 issue of Chevy High Performance
By John Nelson
"Primer is like the foundation of a house," says PPG Product Manager Jeff Griffin. "You don't want to build a house on sand (lacquer)-you want to build it on concrete (two-component urethane)."
To be honest, we weren't thinking in such ambitious terms when we decided to go to work on our errant '84 Z28. We were just thinking that anything would look better than the faded, cracked mess covering much of the Camaro's surface. Then again, we have high hopes for this Z, so if the job's worth doing, it's worth doing right. And so we set out to learn what goes into getting a car into primer.
Our talent for this project was Studio Auto Body of Glendale, California. Proprietors Robert and Jeremiah Becker have painted a number of CHP feature cars, and even resurrected one that was sandwiched in a traffic accident ("The Mojo's Workin' Revisited," Sept. '05). We started with the basics, specifically, why do we need primer?
"Paint doesn't stick to bare metal like it does to primer," responded Jeremiah. "Primer is also the last layer of body filler," he continued, "but it mainly helps the paint stick." So there you go: Primer is part of the bodywork phase, but it's also part of the paint phase-the foundation we mentioned above.
The biggest issue facing our Z was the cracking paint. This California car even had surface rust in several places. "If the paint's cracking," Jeremiah told us, "you have to get it all off." This car vividly illustrates an important thing to remember when laying down a primer coat: You can't leave anything beneath the primer that might pop up and cause a problem later. That lesson taken to heart, we asked for a few other primer tips:
* Take off as many parts as possible. You want to sand and prime everything that you can.
* Prepare the surface before body filler. Everything must be properly sanded and degreased before application.
* Prepare the surface before primer. Again, everything must be properly sanded; using lighter-grit paper leaves fewer scratches to be filled.
You notice a theme? The words "preparation" and "sanded" figure prominently here. Jeremiah and his ace bodyman, Jose Garcia, took three days to get our Camaro into primer, and very little of that time-less than an hour, we'd say-was spent actually spraying primer. The rest of the time was spent preparing the car for the spray, and the bulk of that was spent sanding. Sanding, we came to learn, is crucial to laying down a good coat of primer, and for several reasons.
It's important, of course, to eliminate cracked paint and clear, as well as surface rust, so there's no nastiness left behind to ruin the paint. Careful sanding is just as critical to the bodywork. "If it's not sanded right, the filler won't stick," Jeremiah pointed out. But remember this: Primer is also filler. "The goal is to put a nice thick coat of primer on it, filling the scratches and high and low spots," Jose added. Remember those scratches. Sanding smoothes a surface but also creates minute scratches that must be filled. As we'll show you, minimizing scratches by using finer-grit paper when possible saves work in the future.
And what does that future hold? We will be painting this Z-but not yet. Truth be told, we've got a pile of go-fast parts we're dying to try out before we make it look pretty. So we're gonna drive it in primer for a while. "I don't recommend you do it for too long," Jeremiah cautioned. "Primer is porous, and it can crack and get moisture in it." So we'll be limiting our exposure to the elements.
There will still be a bit of primer work to do before we lay on the new hues. "We'll use a long-block with 150-grit paper on it to reveal the high and low spots," Jeremiah shared. "It'll get another layer of primer to fill the low spots, more sanding, then we'll wet-sand it with 400-grit." So there's a decent chunk of work to do. On the other hand, we've done the important prep work, laying the foundation for a high-quality paint job. Here's how we got there. CHP
What we Did:
Bodywork, sanding, and more sanding before putting a scabrous '84 Z28 into primer.
Primer is the foundation for a quality paint job, so do it right.
$225 for materials only; $2,500 with labor
Large sections of our Camaro...
Large sections of our Camaro had been repainted in what our ace paint and bodyman, Jeremiah Becker, said was lacquer. These areas were so badly cracked that surface rust formed. Any areas like this must be taken down to the metal.
"Take off as many parts as...
"Take off as many parts as possible," Jeremiah advised. Sanding and priming these areas will lead to a better paint job. As you can see, we also removed the Camaro's spoiler, rocker extensions, and side marker lights
This pinstripe/decal remover...
This pinstripe/decal remover makes quick work of unwanted stickers without damaging the paint beneath.
Studio Auto Body's Jose Garcia...
Studio Auto Body's Jose Garcia uses fiberglass sanding discs, since they don't flex. As much as possible, the sanding disc should be kept flat; using the edge creates deeper scratches. Jose also advised us not to stay in one place for too long; the heat created can actually warp the body surface.
Most of our Z28's left quarter...
Most of our Z28's left quarter had been repainted and was cracking, so it was taken to bare metal. The gas filler door, on the other hand, was still in good shape. These areas were scuffed enough to remove the clearcoat.
"Many people think, 'Oh, it's just primer,'" said PPG's Jeff Griffin. But there are actually several kinds of primer, as illustrated here. Primer refers to self-etching primer and epoxy primer, which are "strictly for corrosion protection and adhesion to bare metal," according to Griffin. Some body shops-including ours-don't perform this step. PPG recommends it whenever large patches of bare metal are exposed. Primer surfacer is there to fill in small scratches and imperfections. "It's the finishing step of the bodywork process," according to Griffin. "Primer Sealer" is a kind of "insurance policy," he continued. "It helps deal with sand-throughs and provides a uniform color to apply the topcoat to." What else does Griffin want us to know? "First and foremost, obey your local regulations. Second, use a two-component primer with a hardener. It's more durable." Third, preparation is critical. And last? "Treat the primer step as important-or more so-than the basecoat and clearcoat. It'll perform better and give you better paint adhesion and long-term durability.."
Although the Camaro's right...
Although the Camaro's right fender only needed scuffing, spots that need body filler must also be taken down to bare metal. Be careful when sanding plastic or urethane pieces; the paint comes off very quickly, especially at the edges.
Hard-to-reach spots should...
Hard-to-reach spots should be prepped by hand.
Jose uses lightweight body...
Jose uses lightweight body glaze on small areas, then sands it with 80-grit paper on a DA (dual-action sander). Larger areas, like the driver's door, require regular-weight filler, which Jose knocked down with a long-block and 150-grit.
The idea here, according to...
The idea here, according to Jose, is to get a nice thick layer of primer on the car. The gun is set to spray a 4-inch-wide pattern. The primer we used, PPG NCP 280, is very thick, according to our gunman. It took two coats to completely cover the car and give us enough material for sanding.
Our stock steel hood was rusted...
Our stock steel hood was rusted through. Luckily, we had a fiberglass lid from an '82 Z28, so on it went. Prep is essentially the same as the car's metal panels.
Our primer of choice for this...
Our primer of choice for this project was PPG's NCP 280. Although it's a mainly a filler primer, PPG's Jeff Griffin says that this product does have corrosion protection properties. It's also a two-component primer, as it gets mixed 2:1 with the NCX 285 hardener. Studio Auto Body likes it because it's thick, requiring only two coats, in this case. According to Studio's Jeremiah Becker, PPG primer is glossy rather than flat, which gives the impression that the car is painted, allowing you to look down the body and check for straightness. "It's better to see wavy primer than wavy paint," he concluded.
The look of our new primer...
The look of our new primer coat isn't important. What's important is that there's lots of it. A thick coat fills scratches and other small imperfections, and also provides enough material for the next sanding stage.