Exclusive Content
Original Shows, Motorsports and Live Events
Try it free for 14 days
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
Subscribe to the Free
Newsletter

Proper Sheetmetal Prep is the Foundation to Getting Great Paint

The perfect paintjob comes from prep and discipline

Jim Smart Aug 12, 2019
View Full Gallery

Getting perfect paint has never been for the faint of heart. There's a tremendous amount of labor involved, whether you do it yourself or take it to a trusted body shop. If you take it to a shop, just know that most body shops tackle fast-paying crash and insurance work first, then get to your weekend toy when they have time.

If you're going to tackle getting great paint yourself, you're going to have to be patient and tenacious because it won't get great by itself. If your project begins with a damaged and rusted body, be prepared to burn a lot of midnight oil because great paint is all about proper prep. Sheetmetal replacement and rust repair take time and are just the beginning of getting a great paintjob.

Joel Rode of Hot Rod Specialties in Upland, California, tells us to lay down paint that will endure the passage of time you need a good foundation. Although Joel doesn't paint cars himself, he understands the fundamentals of preparation before it goes to the body shop for paint. Learning how to do the prep work yourself is a good way to save some money.

We've found the original factory finish on most cars is a good foundation for a sound paintjob, depending upon when your ride rolled off the assembly line and the condition of the finish. If you're doing a 1980's vintage Chevy Malibu or Monte Carlo SS be prepared to take it down to the metal. Many of these rides assembled during the "big hair" era had those first waterborne basecoat/clearcoat finishes that fell off the body in sheets. Do not use these finishes as a foundation.

Lacquer and enamel finishes factory-applied in the 1960s make good foundations for a paintjob because they were solvent-based and hard as a rock. Otherwise, expect to take your bodywork down to raw steel and begin with a good self-etching primer/sealer to start off. We prefer to see pure raw steel followed by a phosphoric acid etch body wash before the primer/sealer is applied. Phosphoric acid etches the surface, promoting good paint adhesion and corrosion resistance. Once you have etched the surface, perform a Dawn dish soap wash with Scotch-Brite to rough up the surface, then blast the surface and seams with a pressure washer followed by compressed air to remove all moisture and contaminants.

You want to clad the body in primer/sealer immediately to prevent surface rust, which will happen right away in a damp climate. Steel is more forgiving in a dry climate, but not for long. Before applying primer/sealer, take compressed air and blow off all surfaces and seams, working with a tack (static) cloth. Once your primer/sealer foundation has been applied and has cured, you're ready to perform surface prep.

Follow the paint manufacturer's instructions to the letter because good paint is all about chemistry and following instructions. We're using Axalta Cromax finishes on our third-gen Nova restomod project, paying very close attention to the instructions. Because today's automotive finishes consist of paint and a catalyst to cure the paint, we know to mix in just the right amount of catalyst for the environment or the results will be less than satisfactory.

Today's automotive finishes work in a similar fashion to body filler. The catalyst we add to the paint is like the hardener mixed into body filler to make it cure. Too much hardener and it cures too quickly and becomes brittle. Too little and it will never cure.

Once you have a solid foundation in place, it's time to work out the irregularities—many of which you cannot see with the naked eye but will see when it's time to lay down the clearcoat. Primer/surfacer is the next finish applied over the base primer/sealer coat. Primer/surfacer is your filler primer, which can be thin like paint or thick like a filler to work irregularities. Filler primer is what you use to refine the surfaces while on your way to a perfect surface.

And finally, there's the guidecoat, which is a differing color than the primer/surfacer coat. The guidecoat is a light dusting of contrast color paint that enables you to see imperfections—high and low spots—in the surface when it's time for final block-sanding. If you're using a light color primer/surfacer, the guidecoat should be dark. If you're using a dark primer/surfacer, the guidecoat should be light.

The color of your primer/surfacer should mimic the body's final color coat. Light color primer/surfacer for light colors and dark primer/surfacer for dark colors. Always opt for the same manufacturer from primer/sealer to final color coat. Never mix manufacturers.

Getting great paint boils down to due diligence and undying discipline. The more time and attention you pay to perfecting the foundation the better your paintjob will be. The proof of the pudding will be when you lay down the clearcoat and behold the result. No matter how exhausting preparation may become, stay with it and feel good about the result. CHP

2/26

We're working with a 1969 Chevy Nova that suffered from extensive rust. Joel Rode of Hot Rod Specialties has replaced all of the rusted sheetmetal and extensively worked the body to the stage it is here, ready for final prep and paint.

3/26

Getting great paint calls for discipline, tenacity, and the right tools. You need short, medium, and long sanding boards and blocks depending on the type of surface you will be preparing. Long boards are good for broad surfaces where you're cutting a large area. Medium and short boards and blocks are good for smaller areas. You will also want a broad selection of sandpaper grits ranging from 40- to 80-grit for heavy cutting all the way to super-fine 1,000- to 1,500-grit for the home stretch.

4/26

Joel performs the initial cutting of primer/surfacer with 80- to 120-grit to find the low and high spots. Filler is applied as necessary in the low spots, and then more cutting is performed with 240- to 400-grit. For shallow irregularities, apply a filler primer such as Chromapremier PRO Productive Primer Filler 33430S that is compatible with your paint.

5/26

One of the biggest mistakes we see in bodywork is the use of the wrong filler or improper mixing of filler and hardener. Follow the manufacturer's directions to the letter and mix the filler and hardener thoroughly before applying. We're using Evercoat Z-Grip lightweight filler.

6/26

The first cut with filler should be a cheese grater like this one or ultra-coarse 40- to 80-grit paper. Then, cutting toward a transition to 120- to 240-grit as you work the surfaces.

7/26

Once you get past the heavy-duty grunt work of filler and surface irregularities it's time for the final guidecoat, which helps fine-tune the surface. A guidecoat looks like this with a light dusting of black spray paint. The guidecoat reveals low and high spots as you work the surface. You will see the high and low spots immediately when you start wet blocking.

8/26

Joel works the concave spots with wet 400-grit to fine-tune his prep work. Sometimes, he uses his fingertips or a dowel rod for concave areas. Wet sanding with a flexible block perfects the surfaces.

9/26

Broad surfaces like doors and quarter-panels get medium and long boards. Wet sanding with 400-grit begins when heavy cutting is complete.

10/26

This head-on shot of before (left) and after guidecoat block sanding (right) shows the difference between guidecoat and the wet block-sanded guidecoat. The guidecoat followed by block sanding finds the low and high spots.

11/26

Justin Smith of Superstition Restoration, who is painting our Nova, tells us doorjambs are painted first, as are the insides of the doors, hood, and decklid. All exterior surfaces are painted last. Doorjambs and internal surfaces are painted first to minimize the risk of overspray on outside surfaces.

12/26

We're using an Axalta Cromax urethane basecoat engineered for medium temperatures. The type of Chromabase Basecoat you use depends on where you live. Chromabase Basecoat is a solvent-type basecoat designed for spot, panel, and overall repairs. Axalta 7175S is optimum for full-scale paintjobs and repair work. Check with Axalta for information on which finish you're allowed to use by law in your state.

13/26

This is part of the jambing process where the door, hood, and deck jambs get painted with Chromabase 7175S. The basecoat is applied first as a color foundation. Apply two or three coats of Chromabase until the primer is completely covered. Allow a flash time of 5-10 minutes between coats. Allow 30 minutes to fully cure. Always check with the manufacturer on drying times for your paint product.

14/26

The color basecoat has been applied and has cured (dried). This looks mighty dull as applied, but will come alive when we apply the clearcoat.

15/26

The body gets a wipe down with a tack cloth and compressed air to eliminate any dust. Compressed air helps dislodge any debris that might be trapped.

16/26

The first color coat is very light to allow the basecoat to gas off and cure as a good foundation before laying down the following coats. Each coat needs to be light, then a final "wet" coat on top. You want to ensure full coverage by the time you spray the final coat.

17/26

Justin lays down a light first coat over the entire body, spraying in a uniform pattern from end to end with each pass.

18/26

Your first coat should look like this with mostly body color and some primer showing through. Don't get in a hurry to pour it on or you will wind up with runs. Allow each coat to cure (around 30 minutes each) and spray the next coat.

19/26

This is the second coat going on. It is crucial to be patient with each coat. Ideally, you will lay down three to four coats. This means two or three light coats and a final "wet" coat where the finish looks shiny while wet.

20/26

By the time you get to the final coat it should look like this when cured—a dull, satin finish. Do not touch the surface. You don't want skin oil on the basecoat anywhere, which can contaminate the clearcoat, causing fisheye and other irregularities.

21/26

This is the final basecoat finish, which to the first-time painter can look disappointing because it is dull. It is supposed to be dull, which promotes good clearcoat adhesion.

22/26

The hood and doors have been painted with Axalta Chromabase basecoat and are ready for the clearcoat.

23/26

Our Nova is fully clad in Axalta Chromabase. We're ready for the clearcoat, which must be applied within 24 hours of the basecoat for a good bond.

24/26

After a thorough wipe down with a tack cloth and compressed air, it's time to spray on the clearcoat. Clearcoat, like the basecoat, is applied modestly for the first coat, then a "wet" final coat without overdoing it. You don't want runs in the clearcoat.

25/26

The second coat of clear is applied here as shown. We're laying it on "wet" without overdoing it. Nice even passes are applied without stopping. If you stop at any one point you can expect runs. Two clearcoat passes are suggested.

26/26

Check it out. The doors have been hung and are already adjusted. The hood is left to go. This demonstrates what you can do with tenacity and patience. Joel Rode is not a body man, yet he has shown us what you can achieve if you take your time, work out the kinks, and follow Axalta's instructions.

 

Sources:
Axalta Coatings
855.629.2582
axaltacs.com

Hot Rod Specialties
909.215.5516
hotrodspecialties.net

Superstition Restoration
480.252.6893

 

Photography by Jim Smart, Joel Rode

 

 

Sources

Axalta
855-547-1461
http://www.axaltacs.com
Axalta Coating Systems
855-547-1461
http://www.axaltacs.com

MORE PHOTOS

VIEW FULL GALLERY
X

Connect With Us

Get Latest News and Articles. Newsletter Sign Up

sponsored links

subscribe to the magazine

get digital get print
CLOSE X
BUYER'S GUIDE
SEE THE ALL NEW
NEWS, REVIEWS & SPECS
TO TOP