Much of the information in this article comes from an article by Terry Freiberg of Proper Auto Care. The material is being used here with the permission of the author.
If you are like most detailers you have probably had customers ask you if the clear coat on their German car is softer than the clear coat on American cars.
Soft clear coat? What kind of question is that? Paint finishes, especially clear coat finishes, are supposed to be hard.
If you do not really know the answer and you did your due diligence and called a BMW dealer, for example, you probably would find it a fruitless exercise, because no one would be able to tell you anything about the paint system on the cars.
Freiberg encountered that, but was more tenacious in his search for information. He then contacted his suppliers, one in Germany, and that generated three industry contacts.
One was a paint consultant to BMW-Munich; a second was a paint consultant to Mercedes-Benz-Stuttgart; and the third a recently retired paint consultant that worked for Chrysler in the United States.
Fortunately for Freiberg, both German people spoke perfect English. All three contacts did ask to remain anonymous due to confidentiality agreements, but here is what he found out about German paints.
From his research Freiberg found out that German paints really are different. Why? Because German paints use a “solvent package” (mix of base solvents) that cannot be used in the United States, due to regulations regarding solvent emissions dictated by the Clean Air Act and administered by the Federal EPA.
Asking why German companies continue to use high V.O.C. (volatile organic compounds) solvents in their paints, he received two candid answers:
• One, the Germans feel their paints have an intensity and vividness that U.S. paints lack. As one of the German contacts told him, “German paints have passion!”
• Two, the other German consultant simply said: “That’s the way we do it.”
So are German clear coats “soft?” Yes, they are — at least, they are softer than U.S. clear coat finishes.
In the United States there are a number of paint suppliers to the automakers, but only three are considered major: PPG (#1), DuPont (#2), and BASF (a distant #3). Both PPG and DuPont have focused on creating super-hard clear coats. These “rigid” clear coats are more resistant to chemical etching, which makes them less susceptible to acid-rain etching and swirls created by improper washing/drying and improper buffing and polishing. The major disadvantage of these rigid clear coats is their propensity to chip when struck by stones or road debris.
One theory suggested that perhaps, because the German Autobahn has higher speed limits, the German automakers have settled on a less rigid, or more elastic, clear coat to avoid chip damage. German clear coats are less likely to chip when impacted by stones and road debris, but are more susceptible to swirls if improper compounds, incorrect buffing pads, and poor buffing techniques are used.
POLISHES AND WAXES TO MATCH
Are some polishes and waxes better for German paints? With regard to waxes or protective sealants, all three experts said “no,” but added one caveat: After the paint is cured, the choice of what wax or sealant to use is an aesthetic or ease-of-application decision.
As far as the paint is concerned, neither German specialist felt that one wax or sealant was any “better” than another. For what it’s worth, the BMW consultant used a carnauba wax and the Mercedes consultant preferred a paint sealant. Both consultants indicated that if a one-step, cleaner/wax was used, it should be a solvent cleaner, not one that contains abrasives.
However, with regard to compounds and polishes, some are better suited than others for German clear coats. Both consultants felt that many American-made compounds and polishes contain abrasives that are too large and too aggressive for German clear coats. They also felt American detailers are in too much of a hurry buffing and polishing at too high a rate of speed.
Their recommendations for compounding or polishing German clear-coat finishes are:
• Use water-based or mild solvent products
• Use a non-abrasive polish for routine cleaning or a polish with only micro-fine abrasives for defect, swirl, scratch, and oxidation removal
• If using a rotary buffer, keep the speed below 1,000 rpm
• Use a microfiber applicator if polishing by hand and a foam pad designed for German clear coats if using a buffer (more later)
TOOLS TO MATCH
BMW and Mercedes-Benz use both the dual-action or orbital and the rotary buffer on the assembly line for polishing and defect removal. The trend, however, is to move away from rotary buffers toward the dual-action/orbital machines.
This trend is also occurring in the United States but there are varieties of dual-action machines on the market that are different. For example, the Porter Cable 7424 is different from the more professional dual-action machines made by Flex, Festool, and Rupes — not to mention air-powered dual-action polishers. These have a “throw” of up to 1/2 inch as compared to the “wiggle” of the 7424 PC orbital.
These professional tools claim 95 percent of the defect removal of rotary buffers without creating any swirls in the finish. These are professional tools being used by professional paint technicians on paint right out of the oven.
Of course, keep in mind that they are working on defects that are on brand-new paint, which are different from defects in a paint finish that might be two or three years old.
All three consultants felt that dual-action machines like the Porter Cable 7424 or the others mentioned, when used with the proper foam pads, are not only safe for the softer German clear-coat finishes but also recommended for maintaining the very highest paint gloss.
Only the BMW consultant waxed his car by hand, but uses the Flex tool to remove swirls and restore maximum gloss.
Both German paint consultants agreed that:
• Compounding and polishing softer German clear coats are more difficult because these finishes are less forgiving.
• Molded urethane, flexible-backing plates are vastly superior to the rigid backing plates commonly used in the United States. These backer plates eliminate spontaneous heat build-up that can occur when transitioning over curves or when working with the edge of the pad. Flexible backer plates are also particularly valuable when using a professional, rotary buffer for compounding and polishing.
• The newer dual-sided foam pads, which attach to the tool by a chrome screw-on attachment, are even better.
• Both BMW and Mercedes-Benz use flexible backing plates on assembly line machines, the very best coming out of Europe.
• Only thermally reticulated urethane foam pads with “exploded” or open cell structures should be used.
Both German consultants also recommend using the Swiss-made orange power pad for compounding and scratch removal rather than traditional (yellow) compounding pads. They feel U.S. compounding pads are best reserved for the rigid clears used by U.S. automakers.
There are also thick, green pads developed by Mercedes-Benz and used on their assembly line in Stuttgart. Mercedes, in particular, has done extensive research into pad technology. The polishing pad they use in Stuttgart on the Mercedes assembly line for polishing is three inches thick.
It should be clear then that a detailer can no longer view every car and every paint finish in the same way. This article only “scratches” the surface of what you need to know about paint finishes. Certainly, it does make you aware in a basic way that there are differences between German paint systems and American paint systems. But what about other European manufacturers such as Land-Rover, Rolls Royce, Bentley, Ferrari, Lamborghini, Fiat, Volvo, Renault and the all of the Japanese and Korean manufacturers? You need to know what you are dealing with before taking a buffer to a car.
Unfortunately, there is no single source available to help you find all of this information; you have to be tenacious in your search for knowledge. Among other sources, the Internet is a marvelous tool for education.
Bud Abraham is a 40-plus-year veteran in the car wash and detailing industries as a manufacturer, distributor, operator, and consultant. He was a founding member of both the Professional Detailing Association and the current International Detailing Association and their first executive director. He conducts seminars on detailing at industry events and consults worldwide. You can contact Bud at firstname.lastname@example.org.