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Clearcoat finishes: Tips from a master detailer
Today, on many makes and models of cars, there is a whole new system of finishes, high-tech car paints which differ fundamentally from their predecessors in construction and in the way they must be cared for and detailed.
In simplest terms, the final, top layer of finish on all cars of the past, and still on some today, is a pigmented paint. Detailing these conventional finishes, you work directly on the car's color-the paint layer that gives a car its color. Using polish or cleaner, color actually comes off on your polishing cloth or buffing pad if the paint, aging, is oxidized. But this does not happen if your car is clear-coated.
On cars with a clearcoat finish, the paint's color layer lies protected by a clear, colorless, usually urethane or polyurethane final finish. The urethanes are part of a new family of high-tech car finishes.
The urethanes and polyurethanes--often called the 'clearcoat' because they comprise the clear, see-through final top finish overlying the pigmented paint layers-are more forgiving than conventional finishes, yet, oddly, they need more care.
Faults in the clearcoat finish can be more easily corrected than in such pigmented finishes as enamel, acrylic, lacquer, or other conventional car paints. Scuffs or scratches in these pigmented paint layers are difficult to correct. For one reason, a scratch or deep scuff actually penetrates, and likely mars or even discolors, the finish's pigmented color layers, since the paint's color layers are the finish's top layers.
In the clearcoat, many scuffs-minor scratches, for example-never reach the paint layers. And while in the clearcoat they may be visible, they are usually not nearly as obvious as would he damage to the finish's color layers.
Still, the clearcoat is vulnerable not only to casual damage, but to environmental damage and degradation. The clearcoat, to maintain its luster and impregnability, demands more frequent washing: once a week, certainly.
An example of casual damage is the scuffing and scratching that happens when somebody uses his or her car as a shelf for a shopping bag. Slide the bag off the clearcoat, and you leave a scuff mark. With clear-coating, a scuff mark like that is relatively easier to repair than when the damage is in the top, color layer of conventional paint.
Protecting clearcoat from environmental damage
Environmental damage is a clear and present danger to the clearcoat. And even more so than for conventional finishes. If you live in an area where there's a lot of traffic or you commute long distances, carbon black from other car exhausts builds up on the clear-coat. Live or drive near an airport and there's fallout from jet fuel. In industrial zones of the Eastern and Northeastern states, and moving farther south every year, is industrial pollution, including acid rain. Acid fog is common in Southern California. So, in the industrial north, is acid snow. Include, too, early morning's acid mist. Every form of precipitation carries the threat of acid fallout and clearcoat damage.
What happens is this: If your car isn't frequently washed, it becomes coated with acid fallout. A light rain, a morning mist, fog, or dew mixes with the acid particles, putting them into solution. Now your car's finish is wetted with an acid solution. All that's needed for catalytic activity-an increase in finish-destroying chemical action-is heat. It doesn't take much sunlight to supply it. And you have all the ingredients for acid-burning the finish. It probably won't happen in one day, or two. Or even a week. But the damaging process, unless you frequently wash your car, goes on day after day: more acid fallout, an ever stronger acid solution, more catalytic action spurred, day after day, by the sun's heat and light.
Only washing the car to rid it of acid fallout breaks this potentially damaging cycle. That's why it's so important, especially with the clearcoats, to wash your car frequently.
Washing your car's clearcoat
The key to washing a car to rid it of acid build up is to use the right techniques, the right products, and the right tools.
Two things are basic: (1) you don't ever want to wash your car in sunlight, and (2) you don't ever want to wash a hot car.
Before you use a wash product on a sun-warmed hot car, rinse it with cool, clear water. Rinsing washes away the heaviest concentrations of atmospheric pollutants. And, just as important, pre-rinsing cools the finish.
Neglect the pre-rinse, and you aid and abet chemical activity. The reason is basic: the chemical activity of many car wash solutions, among them the detergents, is accelerated by a car's body heat. A chemical reaction is produced which can either streak or burn the finish, especially if it's a clearcoat. Before you use a wash product, rinse the car with a flood of cool water. Rinsing quick-cools a hot car. Also, a clean water pre-rinse also gets rid of possibly abrasive materials.
Basic clearcoat systems
Understanding your car's clearcoat is a first step toward properly caring for-and detailing-it.
Currently, there are four basic clearcoat 'systems,' although the technology is changing rapidly. There are urethane, polyurethane, polyester, and fluorine high-tech clearcoat systems. All are pretty much built up, layer by layer, in the same way: you've got a primer coat (the first coat on the car's bare metal skin), then one color coat or several (this is the 'base coat,' which is often surprisingly thin), and lastly, the far thicker final clearcoat.
The color coat can be quite thin in clearcoat finishes because all it does is introduce the color. When, in conventional finishes, the color is contained in the final paint layer, the color layer is quite thick because it serves both as the color-carrying layer and as the final, protective top coat. Today's clearcoat is probably twice as thick as the combined thickness of the primer and colored base coats. It's not unusual for the clearcoat to have three times the thickness of the color (pigment) coat-and sometimes more.
Clearcoat: A see-through solar window
Consider the clearcoat as a kind of window. As viewed through the clearcoat 'window,' the base coat is dull. What illuminates and adds luster to it are properties in the clearcoat--among them screening agents which screen out ultraviolet rays, which, in conventional car finishes, bleach and fade the color layer. The clear-coat's ultraviolet screening agents also protect the color coat from fading. Conventional finishes have no such protection. So, what you have in the clearcoat is not just a window, but a 'solar window.'
You've got to keep that solar window clean to maintain, in the color finish, what the industry calls 'DOI,'-Distinction of Image. In essence, DOI is the deep gloss you are trying to maintain in your car's finish.
To test for this reflective depth of image, hold a newspaper over the finish. If you can read it from its reflection in the finish, you have depth and clarity in the finish. The same thing happens when, polishing or waxing the clearcoat, you look into the finish for a reflection of yourself. Detailing or clearcoat flaws show up when your reflected image is wavy or imperfect.
In detailing, you aim to achieve a 'slippery wet look' in the finish. One example is the wet look of those faddish cars painted with 'neon' colors. The dazzle colors you see are the result of looking through the finish's clearcoat window. For most cars, however, the wet look achieved by the clearcoat is harder to describe precisely-even though it's one of the beauties you get with a clearcoat finish.
Abrasives: Clearcoat's kiss of death
But you can destroy that look if you use the wrong products in detailing the clearcoat. The clearcoat is not designed to have anything-let me repeat and emphasize, anything-used on it which is abrasive. Anything abrasive used on the clearcoat can scuff and scar its surface. Abrasives are the kiss of death to a clearcoat finish.
Now, when I emphasize no abrasives, I'm talking about products used by the do-it-yourself detailer. Paint service centers, in repairing clearcoats and when finishing a newly repainted/clear-coated car or repair, do use 'abrasive' products and techniques. Commonly used by pro-detailers is ultra-fine wet sanding paper, with an almost non-abrasive 1500-2000 grit rating. Wet-sanding enhances the clearcoat finish by removing sags, dust, and other flaws. Flaws removed, the new clearcoat finish is allowed to dry anywhere from 72 hours to 30 days, and then, when cured and dry, is cleaned with a non-abrasive cleaner and then polished. Finally, the clearcoat is waxed.
Certainly the skilled weekend detailer can wet sand a clearcoat when virtually everything else has failed to restore its original, 'new car' look. But you need skill and a 'feel' for the clearcoat to do it without further surface damage.
Choosing the right wash product
Now, in washing the clearcoat--and, in fact any automotive paint finish-you should use a wash product specifically formulated for car finishes.
I know, dishwashing detergents have been recommended for car washing. On the basis of overwhelming evidence, I totally disagree. Dishwashing detergent is formulated to wash dishes-specifically, to remove grease. That same formulation is going to remove the wax from the car's finish and also any protective silicones. Silicones are contained in many car polishes and in some car waxes. Use dishwashing detergent and you remove them-which means, at the very least, that every time the car is washed with detergent you have to reapply polish and wax.
The same de-waxing occurs when you put your car through some commercial or coin-op washes: the detergents generally used, because these wash places' main goal is to turn out clean cars, are strong enough to remove most of a finish's waxes and silicones.
Saying this, I have to again concede that some professional detailers use all-purpose cleaners and dishwashing detergents. They do so for the very reason the do-it-yourself detailer should seldom, if ever, use them. The professional detailer wants to strip all the wax from the finish. This enables him, starting from scratch, to better polish and wax the car. Eliminated by using those products is one of the chores he'd normally have to do-remove the wax.
Unless, after washing the car, you intend to polish (glaze) and wax it, you don't want to remove the wax. You don't because the wax's purpose isn't simply to 'shine' a car's finish. Wax forms a protective barrier and also a slipperiness which tends to deflect street debris, such as stones, which might otherwise chip the finish. It also resists scuffing, caused, for example, by somebody rubbing against the car in a parking lot. The wax, being slippery, reduces possible abrasive damage. The analogy is the difference between a waxed kitchen floor and one that's unwaxed. Drag something across an unwaxed floor and you leave scratches. Drag something across your car's unwaxed finish and it scratches.
If you've waxed the car, you certainly don't want to undo what you've done by washing it with an aggressive, all-purpose cleaner. If a wash solution degreases the finish or body parts, you can be sure it will also 'de-wax' the finish.
To wash clearcoats, use any of a number of products specially formulated for clearcoat washing. Almost all are liquids, not powders. Powders may not completely dissolve in your wash water. The tiny, undissolved granules have the potential to become abrasives.
Defining the just-right clearcoat wash product
The proper and ideal slippery, soapy solution for frictionless dirt removal from an automotive finish, including clearcoat, can be defined by a number of characteristics:
- High-foaming-inherent cleaning action
- High lubricity-slipperiness, like a lubricant
- Free-rinsing-a solution which, in itself, leaves no residue
- pH balance-a product with an acid-alkaline balance which is slightly alkaline to counter the acidic nature of a finish's collected fallout pollutants
What commonly available wash products fit these criteria? There are several available (check labels carefully). The choice comes down to personal preference.
Clearcoats must also be critically washed in a specific way. The 'tools' you use should be just as critically designed for clearcoat washing. Among these tools are natural fiber body brushes, synthetic-wool washing mitts, sponges, and terry cloth towels.
Washing clearcoat finish
Whatever washing tools you use, the basic washing techniques for clearcoat are the same. First, you hose and clean-water flush the finish to remove any loose dirt or pollutants. Then you wash the finish with a free-rinsing wash solution.
The first step-flushing with water-purges the surface of anything loose that can be quickly and easily removed.
If any dirt remains, it's got to be removed with a minimum of friction. What is likely holding dirt on the clearcoat finish is surface tension. To remove stubborn dirt or other stick-to-surface materials-bird and tree droppings being the most common-you've got to disturb the surface tension without creating friction enough to scratch the clearcoat.
Ideally, what you want your wash solution-your wash water-to do is 'free-rinse,' that is, to dislodge and rinse all pollutants, including abrasives, from the clearcoat and hold them in frictionless, non-abrasive suspension within the wash water. What does it is a soapy, slippery wash solution that meets the criteria for an ideal clearcoat wash product.
Keep these same criteria in mind when choosing your washing 'tool.' A sponge is not a free-rinsing tool, because grit and dirt can get caught in the sponge's pores. You're going to trap dirt and grit in the sponge, even if you wash with a soapy solution that has high lubricity and is high-foaming, two of the more important criteria of a clearcoat wash solution.
The ideal tool for washing clearcoat finishes is a natural fiber body brush. This usually imported, bleached pig's hair brush is super soft. Commonly, the hair is set into a mahogany block with epoxy cement.
Natural fiber body brushes (they're designed for car washing) are user-friendly tools for washing clear-coats. Using them, you need exert only minimal pressure. That means less friction on the clearcoat-and less washing effort, too.
The brush has a nap that's about 3 inches (76mm) deep. You use only the tips of the brush's super-fine hairs- just the first 1/4 to 3/4 inch of the nap. You use very little pressure. All you want to do is loosen the dirt's surface tension and get the dirt into the carrier solution-your soapy wash water or finish shampoo. If you can't find a body brush, then use the second-choice 'ideal' clearcoat washing tool: a synthetic wool mitt.
One caution: Not all car wash brushes are the hog hair-China bristle natural fiber kind I'm describing. Some, with coarser hair, may be too aggressive-too abrasive-for clearcoat finishes.
You may have to settle for something less than the ideal clearcoat washing tool. A terry cloth towel, perhaps, or even a sponge. If you keep them forever lubricated in your wash water to make sure they are clean, and if you use them carefully and with minimum pressure, they'll generally do a satisfactory service on clearcoat finishes.
Clearcoat polishes and cleaners
The use of abrasive compounds on clearcoat can be fatal to the finish.
Polish. A lot of detailing pros use the words 'polish' and 'glaze' interchangeably. As if they are the same things. Generally, they are not. A polish is a polish. A glaze is a glaze. And a cleaner is a cleaner. Whatever the product, use the least 'aggressive'-the least abrasive. A more abrasive product generally gets the polishing service done faster. But an overly aggressive polishing/cleaning product also risks scratching, and in fact removing, some of the finish-such as the clearcoat.
A polish is a minimally abrasive cleaner and lusterizer. A cleaner, more aggressive than a polish, contains chemical cleaning agents. Even more abrasive-often very abrasive-are compounding products. Compounds are sometimes the preferred products for treating heavily oxidized conventional finishes. Using a compound-called 'compounding'-you are apt to remove paint as well as oxidation. Today, the cleaners-far less abrasive than compounds-are usually all you need to work with on even the most oxidized conventional finishes.
While compounds can be used-and still often are-on conventional paints, their use on clearcoat finishes risks major damage. The minute particles of pumice, which give the compounds their cutting action, cut little holes in the clearcoat. The result: 'swirl' marks which are difficult, and sometimes impossible, to remove from the clearcoat.
'Swirls' are residual evidences of abrasive polishing. There should, of course, be no evidences in a finish that it has been polished-just an even, unbroken, reflective shine. Hand-polish swirls are irregular, non-reflective blotches in the finish's polished surface. Machine-polish swirls-evidence of machine buffing- tend to be circular blotches. Swirl marks are the nemesis of detailers, whether pros or weekenders.
If you get swirl marks when you buff a finish by hand, it means there are abrasive particles in the product you're using. Or, perhaps, some abrasives in whatever you're using to apply the product-a rough towel, for example. Or a foam sponge applicator that's not clean and has some grit or hardened cleaner in its pores. In short, there are only two ways that swirls develop when cleaning, polishing or buffing a clearcoat. finish: (1) the product you're using, whether hand-or machine-applied, is too abrasive; (2) the polishing tool is abrasive.
In machine polishing, the problem is often a wool buffing pad. Wool buffing pads are, by their very nature, abrasive. Wool buffing pads are an anachronism in today's era of high-tech car finishes, as clearcoat. They are plainly out of date, although wool buffing pads are still being used on conventional finishes. But not on clearcoats. There's no question about it: in machine buffing, wool buffer pads are the number one swirl-maker.
Today's preferred and widely used machine polishing pads for clearcoat are made of synthetic foam. They all but eliminate swirl marks, and they can be used on both conventional and clearcoat finishes.
How do you know if it's clear-coated?
One vexing question: How do you know, in this era of fast-changing technology, whether your car has a conventional or clearcoat finish?
It isn't always easy to tell. One test is to gently rub an out-of-sight place on the finish with a mild cleaner. If color comes off on your cloth, you can be fairly sure it's conventional finish. If no color comes off, you can be almost as sure it's clear-coated.
Still, there's only one sure-sale rule-of-thumb: When in doubt, treat it as a clearcoat finish. Obviously, if your car is clear-coated, it needs special handling and special care.
The advent of "no-wax" clearcoat finishes
The newest technological advancement in clearcoat finishes is a fluorine-type clearcoat that needs little or no waxing. Currently available on Nissan Motor Corporation's Infiniti luxury automobile, "no-wax" clear-coats are likely to be available on other cars and from other manufacturers in the future.
The fluorine-type clearcoat finish requires special detailing, especially to correct damage to the clearcoat, and should be treated exactly per the manufacturer's instructions in the owner's manual. Polishing and waxing in the usual detailing sense are not appropriate for these high-tech finishes.
For the Infiniti, the manufacturer outlines particular procedures and brand-name products for buffing out fine scratches in the clearcoat finish and for wet-sanding finish damage that remains after buffing. Because no-wax/minimum-wax finishes are so different from conventional finishes and from most other clear-coat finishes that have been available to date, it is likely that each manufacturer that produces such a finish in the future will also include very specific product and procedure recommendations for its individual formulation of no-wax clearcoat.
Detailing a scratched or nicked windshield
Most windshield scratches or nicks defy do-it-yourself fixing. And, in fact, fixing at all. Pro-detailers and windshield glass specialists have a "rule of thumbnail": if, rubbing a thumbnail across the scratch, you can feel the scratch, it's probably too deep to fix.
A tiny surface scratch can sometimes be rubbed or buffed out with very fine powdered pumice or with jeweler's rouge (both are available from glass shops). Make a heavy paste using water and pumice (or jeweler's rouge). Spread the paste on and around the scratch. If machine buffing, use a non-abrasive foam buffing pad on a low-speed orbital buffer. Use very gentle pressure while buffing. You may have to re-apply the paste and rebuff several times to buff out the scratch.
Rubbing out the scratch manually involves the same water and pumice/rouge technique, only you use a very soft, non-abrasive cotton cloth as your rubbing tool.
While deeper scratches can sometimes be removed by machine buffing, the result is seldom satisfactory. Although you may rid the windshield of the scratch, deep buffing causes a concave place where the scratch was. Result: Vision through the former scratch area is distorted. Far better to keep the scratch than to cause windshield-and vision-distortion.
On the market are a number of "fixit" kits for reducing the visibility of windshield nicks, rock pocks, and scratches. Generally, the results are not very satisfactory. The patch places are often as obvious as the windshield damage they "correct". In most cases, it's not detailing that an injured windshield needs, but replacement.
Aside from detailing the windshield for visibility and cleanliness, a number of products are available to (I) help keep it clean and clear; (2) reduce fogging or steaming; and (3) disperse rain, snow, ice and sleet.
Rain-X, originally named Repcon and developed for the U.S. Air Force to keep jet fighter windshields rain-free, is a wipe-on liquid that quick-dries to coat the windshield with an optically clear, transparent polymer (plastic) coating, which disperses rain, snow, ice and sleet. Used on windshields, it largely eliminates the "vision tunnels" produced by wipers. In fact, it is often not necessary to operate wipers on a windshield treated with Rain-X. The film causes an aerodynamic runoff of rainwater and snow, clearing the windshield without any, or only infrequent, wiper assist-thus its claim to being "the invisible windshield wiper."
Applied to rear and side windows, and on rear-view mirrors, Rain-X provides greater visibility in rainy or snowy weather. It is also effective on many convertible and off-road car plastic windows. The product is not, however, a defogger. Its useful life varies, depending in part on a car's speed and use. If you commute several hours daily at superhighway speeds, Rain-X may have to be reapplied every few weeks.
Snow skiers have long used anti-fog, chemically impregnated cloths to keep their goggles clean. Larger versions of the anti-fog cloths work well on windshields. You should be able to find them at local ski shops. There are also interior window defogging formulas available.
While there are many useful glass cleaners available, from household glass cleaners to auto-specialized pre-moistened towelettes for quick-cleaning windshields, what cleans them about as well as most commercial products is ammonia and water. The mix: 1 part ammonia to 4 parts water.
To rid windshields of stubborn grime, stains, and bugs, many pro-detailers use super-fine 0000 (be sure it's 4-0) steel wool. The same super-fine, non-scratch grade of steel wool is also frequently used by pro-detailers to polish windshields, especially those streaked by hard-water residues.
The nemesis of interior glass and, in fact, all interior surfaces is vinyl vapor residue: the oily vapor given off by vinyl (upholstery, vinyl dashes, other interior vinyls), especially as vinyl grows older, when exposed to sunlight. The hotter the weather-and the hotter a car's interior-the greater the vaporization of the vinyl. Not all vinyls vaporize as readily as others; nor do all give off equal amounts of vapor.
Most people seeing a vinyl-vapor-smudged windshield or windows assume the driver is a smoker. Maybe, but vinyl vapor leaves a far more bothersome residue on glass-and on the car's entire interior- than any dozen packs of cigarettes. In sunbelt states, especially in summer with the windows shut, vinyl residue can come close to coating interior glass in a single day. Not only is the residue car-disfiguring, it is dangerous, limiting visibility.
To remove vinyl residue, use any good household or automotive window cleaner, an ammonia-water solution, or all-purpose cleaner.
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©1998 W. G. Nichols - Chilton's Easy Car Care