tech

Elusive Paint, a Misunderstood Art
Automotive Paint Practices, Policies and Procedures

By Ryan Lee Price
Photography: Robert Hallstrom

Once driving a faded, oxidized Volkswagen has taken its toll on your patience and you've decided to break down and get the car painted, there are several roads to go down at this point. If money is no object to you, have it professionally painted. End of point. Drive the tattered car in, wait a few weeks or a couple of months and drive the spotless car home. However, like 99 percent of us not related to Daddy Warbucks, money is most certainly an object--a very big object if your significant other believes more in new curtains for the dining room than new paint on the thing in the garage. You might want to find a new significant other, first off. If that's not an option, consider taking it to a day painter where it can be painted and baked almost in a day or two. It is inexpensive, yes, but sometimes it can look cheap it if you don't do the proper prep work. Your third choice is to do everything yourself... teardown, prep and paint...all right in your garage.

Since the question loomed and we had a car we needed to get painted, we towed it down to ISP West, where we learned a few tips of the painting trade. The car in question is a Zenith Blue Standard Beetle that is getting a new coat of Zenith Blue paint. If you're not sure of what paint color you would like to get, but know that you'll pick a stock color, check out www.wolfsburgwest.com, as they have an impressive collection of stock paint colors (matched to the stock interiors) categorized by model and year.

What is Paint?
Auto paint is made up of pigments, binders and solvents. Pigments give the paint material its color. Binders are used to hold the pigment material together (and to the metal as well), while solvents are thinners or reducers that transform the solid pigment and binders into a sprayable liquid. The solvents then evaporate into the atmosphere and are the cause of most pollution concerns in the industry. Before the advent of the high-tech urethane paint of today, cars were painted with either enamel or lacquer products. Enamel was easy to use, covering a car in one or two coats, while lacquer needed several coats and a clear coat, but it had a faster drying time.

Urethane paint combines the advantages of enamels and lacquers in that it offers quick drying times, durability and can cover in one to three coats. The basic three ingredients are the same, but their chemical composition has changed.

The terms two- and three-step paint systems are defined by the number of paints you use. For example, a base coat and a clear coat (clear paint) can be referred to a two-step paint system, while a three-step paint job is the application of two base coats, where the first base coat changes the color of the second, or toner, coat before the clear coat.

What Paint Should I Choose?
If you're taking your car down to bare metal (and for VWs, it is strongly suggested), an acrylic enamel is easiest, with only up to three coats necessary and no rubbing or buffing. However, since nicks and flaws cannot be wet sanded out, you need a dust-free environment. The three-step process described above means more spraying, more buffing, but a much more durable paint job. First timers may shy away from a urethane paint and opt for a lacquer- or enamel-based product due to the concerns over personal safety while using isocyanate hardeners with the urethane. If you have settled on a urethane paint, consider getting a fresh-air respirator. A lacquer is your best bet, as there is no need for the hardener, so you can wear a simple filter respirator and debris in the paint can be wet sanded and touched up with little problems.

Unfortunately, painting your car isn't as easy as buying a gallon of paint and applying it to bare metal. If you simply paint your car without applying any supporting chemicals, you will not get the smooth shine you would expect--and to add salt to the wound--the color will probably fade, crack and/or peel sooner than later.

Most of these extra chemicals are designed to help fix a certain problem with the surface to be painted. For example, there is a flex additive to be used when painting over urethane plastic parts (like modern bumpers) and a fish-eye eliminator will combat silicone residue still on the surface.

Primers have become general terms that describe something you do to prep the metal for paint, but they can describe any sub-base coat that protects the bare metal, fiberglass, etc. to the standards of your climate and environment. Specifically, under normal conditions, it is recommended that you use a waterproof catalyst-type epoxy primer (two coats will do) for two reasons: Since they are waterproof, they protect the metal, and it offers an excellent adhesion to metal and serve as a perfect base for color paint coats.

What Else Do I Need?
Since any surface you might be painting must be as clean and debris free as possible, you may consider purchasing a wax and grease remover. After a thorough and meticulous wash, all bare metal surfaces must be wiped down with a wax and grease remover to avoid imperfections caused from foreign chemicals contacting with the paint (or any of it support chemicals). Use two clean cloths, one dampened by the cleaner and on to dry up excess. Wipe on with the wet one and wipe off with the dry one. The cloths have to be as debris free as possible, so we suggest you buy some flannel at a fabric store, wash it and cut it into usable pieces.

As well, it is recommended that you invest in some tack cloths, which are nothing more than sticky towels that pick up any minute pieces of lint, dirt and other debris.

Before You Begin
You can't just start throwing paint around in your garage, or you'll have your neighbors calling the EPA faster than you can say "hole in the ozone layer" or they'll be reviving your at the ER for asphyxiation. You need to find a suitable location to paint your car, which means you'll have to either find a new friend with a paint booth or shell out the money to rent one. Check with your local phone book or paint supplier for any references--they always know a guy who knows a guy. Failing that, you can make a booth in your garage with sheets of clear plastic enclosing the car on all sides (including the top). Add a fan for ventilation, and don't forget to wet the floor to keep down the dust as you walk around the car.

Break out the sand paper, masking material and the paint. The real work has just begun.

Before you is a Volkswagen much like the one in the pictures here, or parts there of. You've stripped everything off of the car that you don't want to paint, including all chrome, interior, exterior and molding parts. Since we're not doing the trunk, the gas tank can stay in, but the engine's got to go. Pull off all removable parts, including the deck lid, trunk lid and doors. They get painted separately from the body.

Sanding
New paint can be applied over old paint, such as we did here, if the existing finish is sanded to a point where all oxidized paint material is removed and the surface is left flat, even and smooth. If bodywork is needed, the paint has to be striped to bare metal so filler material will bond completely. Of course, each car is different. Some have been painted so many times that the buildup of layers is too thick to support another finish. For this car, since it has it original paint job, we decided that we would do a combination of sanding down some trouble areas but retaining the main body surface for the new coat.

For small dings and dents, body filler is applied to the area. The top layers are sanded with an 80 to 150-grit paper to smooth and flatten rough spots. Then 240 grit is used for additional smoothing. Use a block sander to keep the sanding uniform and consistent; vary your direction and let the sand paper do the work. Every few moments, feel the surface to see your progress. Once the surface is free of ridges, use 320 grit to remove sand scratches and shallow imperfections. The 320 should be used to form a ring around the filler area, so you'll form a layered "valley" of filler, primer and paint. This is called "feathering" However you look at it, sanding is just as an important step as any other in the process, as every blemish will magnify if it isn't taken care of at this stage. If you don't scuff up the old surface before applying the new, more than likely the paint will begin to flake off, as it doesn't have a proper absorbent base to adhere to. Use 500 to 600 grit paper to scuff shiny paint finishes, because the overall purpose is to dull the finish so new layers of paint have something to grab onto. Sand in all directions and cover all surfaces to be painted, in our case, the whole car.

At this point, the car and its parts need to be cleaned with a grease and wax remover. Every surface needs to be thoroughly cleaned. Once you get the car into the paint booth, this step should be done again (as well as the use of a tack cloth). Go over every inch that is to be painted--we can't stress this enough.

Masking and Primer
Masking is essentially a straight forward application of material that will block off the paint spray so it doesn't get to certain areas you don't want it to go. It would be easy to say, "mask off everything you don't want painted," but when doing the whole car, it is more involved than that. Consider the wheels, tires, the pan, the interior tunnel and floorboards, battery area, etc. Use masking paper that is specifically designed for painting, and whatever you do, don't use newspaper, as it is porous and paint will soak through. Don't' forget to mask off the back of the dash, because we don't want any paint inside the trunk area. Let's prime the surface.

Epoxy primers and sealers do not have to be sanded, unless runs or imperfections show up on the surface. Then a fine-grit paper can be used to fix the blemish. Use the minimum recommended pressure and fan spray to gently cover the to-be-painted surface. Feather them into adjacent areas by slowly releasing the paint gun trigger toward the end of each pass.

Let's Start Painting
Okay, we've made several trips to the paint store, the employees there know us by name now, and our wives are wondering what they charges are on the VISA. Seriously, enough talk, let's start painting.

If you're a novice at painting, no amount of equipment or instruction will help you conquer a good paint job. You must practice and learn through trial and error. Get an old hood and follow all of the steps above and below for starters. Mix the paint products according to the label instructions. Try painting with different fan patterns to see which combinations work for this part. Find out what doesn't work. Sand it all off and do it again.

Spray Guns and Fan Patterns
With high-tech paint equipment being what it is, paint guns are no different, and there are different guns for different applications. Whether you are using DeVilbiss, Binks or Sharpe guns, you'll need to be familiar with the material they are each best at painting. On these models (and most others), two control knobs are typical: one controls the fan spray, while the other controls the volume of paint that leaves the nozzle. Set up a test panel (or use some of the masking paper) to see how your nozzle sprays. When the gun is held properly--approximately eight to 10 inches perpendicular from the surface to be painted--the sprayed pattern should resemble a straight line approximately one to two inches wide. A split spray is heavy on each end of the spray and light in the middle. It is caused by two high air pressure for the viscosity of the paint. A crescent shaped pattern is because there is a clog in one of the wind ports that restricts air passage through the gun. Dissolving the material with thinner will correct this pattern. While a spray pattern that is wider at the top or the bottom of the fan indicates that material has dried around the outside of the fluid tip and needs to be cleaned.

When painting, hold the gun perpendicular to the panel, lock your wrist and elbow and walk along the side of the car to ensure a right-angle position. Don't swing your arm or wrist back and forth; move your whole body instead. Each fan spray should overlap the previous one by at least half. For example, the center of the first spray should be centered on the masking line, half on and half off. The next pass should follow the masking line so that the top of the spray is on the line.

If you've practiced enough and feel confident, try it on the car. It should be free of runs and buildup spots. Runs are caused by too much paint landing on the surface at one time. Either your gun is too close or your pass is too slow. Painting a Volkswagen is a difficult thing, especially considering the various curves it has (roof, rear and front quarter panels and the pillars). This is why the doors, fenders and hoods are painted separately, to minimize the amount of corners the gun has to navigate. Plus the fan patterns will line up evenly with themselves on each piece instead of trying to match the whole car.

The Next Coat
Since solvents control the amount of time it takes a paint mixture to dry, it is important not to rush you coats and wait until the surface is completely dry. If you spray a new coat over a coat that hasn't had time to flash (dry) you'll be trapping solvents under the new coat. Those solvents will try to get through with unpleasant results (i.e. blistering, cracking, lifting or sags). Flash times are clearly indicated on the paint products. The flash times for subsequent coats may longer than the first, as they are not all the same.

The Clear Coat
The application of a clear coat helps reduce the amount of color material that has to be sprayed on car bodies, thus cutting down on the level of solvents in the atmosphere (good for the EPA). They are also good for smoothing out sharp paint lines left from custom edges as well as spot paint jobs. Its application is the same as it would be for any other paint (remember the clear coat is all of the paint chemicals without the pigment, or color). Again, wait for the base and color coats to flash before the clear coat is applied.

The Day After
Automotive paint has to dry, but how much? First off, to avoid contaminants, leave the car in the clean environment you painted it in. If you have the facilities available to you there, forced drying can be done with infrared heaters or basic heating elements. Lacquer paint systems need to "bake" the car for at 140 degrees Fahrenheit for 40 to 60 minutes or air dried in 70-degree environment for at least 16 hours. Urethane paint should bake at approximately 450 degrees, but they must be completely stripped, as all plastic and metal parts will melt at that temperature (otherwise they shouldn't exceed 160 degrees). Needless to say, whatever method you choose, allowing it to dry can be the difference between a good paint job and a bad one.

Wet Sanding
Wet Sanding is the process of polishing the top coat of paint, especially the clear coats, to bring out a much deeper shine and gloss (with controlled buffing and polishing). Use very fine 1000- to 1500-grit paper with water (perhaps even a splash of liquid dish soap) to smooth or remove minor blemishes on cured paint finishes. Only sandpaper designed to be used for wet sanding must be used. Not every type of paint can be wet sanded. Enamels, for example, cure with a haze that can be damaged if scratched with sandpaper, so you have to wait a couple of months before polishing. Lacquer paint cannot be sanded directly on the color coats, otherwise it will dull the color, distort the tint and leave a blemish. Wet sanding can be done only the clear coat.

Polishing
Rubbing compounds include relatively coarse polishing grit material that is designed to quickly remove blemishes and flatten paint finishes. Because of its coarseness, light scratches and swirl marks are left behind on the paint. After an application of compound to flatten orange peel or produce a higher surface luster, paint finishes need to be buffed or polished with a very fine grit material. If you're doing it by hand, use a soft, clean cloth for rubbing out and polishing. To cut down on swirls, follow a back and forth motion, from the front to the rear, instead of circular motions.

You're Done
Yes, you just finished. You're standing there looking at your Volkswagen, which is still probably in a million pieces, fenders here, doors there, etc. The next order of business is to put everything back together again, and that's where we leave you to your task.

Care of Your New Paint Job
It is recommended that you not wax or polish your VW in the first 90 days after painting. This will allow the finish to completely dry and cure. (When you are ready to wax, do not use waxes or polishes containing silicone or super polymers) It is recommended that you not use a commercial car wash in the first 30 days (or at all, ever). Stiff brushes or sponges could mar the finish and damage the surface. Wash the vehicle by hand with cool clean water only. Be sure to use a soft cloth or sponge.

Wash the vehicle in the shade only--Never in the sun.

·Do not dry wipe the vehicle... always use clean cool water. Dry wiping can cause scratches.
Extreme heat or cold should be avoided. Keep the vehicle parked in the shade whenever possible.
· Do not drive on gravel roads. Chipping the finish is easily done in the first 30 days.
·Do not park under trees which are known to drop sap or near factories with heavy smoke fallout. Sap and industrial fallout can mar or spot a new finish.
Keep in mind that trees attract birds. Bird droppings have a high acid content and will damage a new freshly painted surface.
· Do not spill gasoline, oil, antifreeze, transmission fluid or windshield solvent on the new finish. If you do...rinse it off immediately with water. Try not to wipe the area, pat dry.
·Do not scrape ice or snow from the surface. Your snow scraper will act very much like a paint scraper on a freshly painted surface.
·Use common sense... If you think some substance or action may be hard on the paint, it probably will.

Paint Pollution

Volatile organic compounds (VOCs) are chemical substances that rise into the atmosphere from paint overspray and solvent evaporation. They combine with nitrous oxide to form the dreaded ozone. To combat this, government mandates have required paint booths to be equipped with down-draft ventilation systems designed to filter out these harmful VOCs. One piece of equipment used to help fight overspray (paint that bounces off of the metal and becomes airborne) are high-volume, low-pressure spray guns. These guns use low pressure warmed air to apply the paint, effectively reducing the amount of overspray and waste.

Ah, Sandpaper

Cracks and blemishes don't fill themselves, folks. You'll have to sand them out. Rather than paint over them and magnify these imperfections, you'll have to spend as much time as necessary sanding the coats of primer to smooth perfection.

Sandpaper is rated according to its coarseness, 36-grit paper is extremely coarse, while 1200 is almost smooth itself. There are types for dry sanding and those for wet sanding. You must use a block to achieve a flat sanding, as your hand only will cause low spots or grooves.

PAINT GLOSSARY
ACETONE --A very fast evaporating paint solvent.
ACRYLIC--A monomer or polymer component exhibiting excellent durability, clarity, gloss and color retention.
ADDITIVE--Chemicals or substances added to a formulation to alter or improve its properties.
BASECOAT--A colorcoat which is designed to be used with a clearcoat.
BLEEDING--Color seeping through or otherwise visible through a topcoat color.
BLUSHING--Hazing or clouding of a finish caused by the absorption of atmospheric moisture while drying.
BRONZING--A surface flaw characterized by a metallic appearing haze on a finish.
BUILD--The level of depth or thickness of paint on a surface.
BUTYL ACETATE--A solvent commonly used in lacquer.
BUTYL ALCOHOL--A medium evaporating paint solvent.
CATALYST--Any component which accelerates a chemical reaction between two or more other components.
CHALKING--A change of a finishes appearance caused by weathering.
CHROMA--The term which defines the level of intensity or richness of a color.
CLEARCOAT--A paint which has transparent pigments or no pigments at all.
CLOUDING--Hazing of a finish.
CRATERING--A flaw caused by paint failing to adhere to a surface due to contaminants.
CRAWLING--A flaw characterized by dry areas of a finish pulling or floating away from wet areas.
CRAZING--A flaw characterized by a distorted surface or cracking.
CURING--The drying of paint by a chemical reaction rather than evaporation.
DILUENT--A liquid filler of thinner formulas.
DRIER--A paint catalyst used to accelerate drying time.
EPOXY--A durable resin characterized by excellent resistance to chemicals.
FISH EYE--A flaw characterized by small openings or craters on a finish surface.
FLASH--The initial drying of solvents characterized by a high gloss appearance changing to a normal gloss.
FLOODING--A flaw caused by color pigments on the surface of wet paint accumulating in an uneven pattern.
FLOP--The change in appearance of a paint finish when it is viewed from varying angles.
FROSTING--A flaw characterized by hazing or clouding of a finish. GLOSS--The quality referring to light reflectivity from a surface. HARDENER--Additive used to accelerate the curing time of an enamel finish.
HAZE--Cloudy appearance of a finish.
HUE--Color.
INHIBITOR--Additive used to slow down a chemical process.
LACQUER--A paint characterized by drying through solvent evaporation only.
LEAFING--The positioning and concentration of metal flakes in a metallic paint.
LIFTING--The distortion of undercoat components from the solvent reaction of an applied topcoat.
LIGHT FASTNESS--The ability of a paint to resist fading from exposure to light.
LUSTER--Gloss.
MONOMER--A simple chemical with the ability to react with itself or other monomers to form polymers.
ORANGE PEEL--A rough surface pattern on a finish caused by poor application conditions or poor flow.
OVERSPRAY--Paint from a spray which has overlapped onto adjacent areas not intended to be sprayed.
OXIDATION--Damage to dry paint caused by atmospheric conditions.
PARTICLE SIZE--Size of pigments in paint measured in mils or microns.
PIGMENT--An insoluble component used to color or affect the color of paint.
PINHOLE--A hole defect on a finish surface caused by paint bubbles.
PLASTICIZER--A component added to a finish to give the finish flexibility when dry.
POLYMER--A chemical combination of monomer components.
PRIMER--Initial undercoat designed for protection of the surface area and adhesion of the topcoat.
PRIMER-SEALER--Primer used to improve adhesion of a topcoat which also seals a previously painted surface.
PRIMER-SURFACER--A high solid primer used to fill small surface imperfections. Designed to be sanded.
REDUCER--A solvent used to thin paints.
RUBBING COMPOUND--An abrasive formula that smoothes and polishes paint finishes.
SAGGING--Excessive paint flow resulting in running or dripping flaws.
SHOW THROUGH--Sanding scratches or imperfections of an undercoat which are visible on a topcoat.
SEALER--A type of undercoat used for even color hold out and leveling of topcoats.
SEEDING--Insoluble particles which may form over time in stored paint.
SHEEN--The quality of surface gloss seen when a surface is viewed from an angle.
SOLVENT--A dissolving liquid.
SOLVENT POPPING--Blistering of a finish caused by trapped solvents evaporating through a dry surface.
STABILIZER--An additive used to prevent chemical breakdowns of paints.
SUBSTRATE--The surface of an area to be painted.
THINNER--A solvent, diluent, or a mixture of solvents or diluents used to reduce paint density.
TOPCOAT--The final layer or layers of paint on a finish.
UNDERCOAT --The first primer, sealer, or surfacer coat of a finish.
VEHICLE--The liquid components of a paint other than the color pigments.
VEILING--Also called cob webbing; webs or strings formed from paint drying while spraying from an airbrush.
VISCOSITY--The consistency level of a liquid measured by its resistance to flow.
WET SPOTTING--Discoloration flaw caused by paint failing to adhere to contaminants on a surface.
WRINKLING--Surface distortion caused by topcoats drying before undercoats have fully dried.
YELLOWING--Discoloration flaw caused by excessive exposure of a finish to light or airborne contaminants.