A Smooth Finish

Jan. 1, 2020
When it comes to buffing

When it comes to buffing—an essential step in turning out a first rate paint repair—there are two schools of thought. Some shop owners are of the opinion that their painters’ time is too valuable to be spent on this step in the repair process. They believe it should be left to those somewhat lower on the pay scale—detailers who put the final touches on the job, inside and out.

Mike Levasseur agrees with that theory, but only to a point. Levasseur is co-owner of Keenan Auto Body Centers in the Philadelphia area. At Keenan, buffing is usually done by one of the detail men, but not always.

“If the job has minor nibs, it goes to the detail department,” says Levasseur. “But if it has excessive runs in it, we have the painter buff them out. Otherwise, the painter turns over everything to the detailer. This way, he has to take responsibility for the kind of job he does with the spray gun.”

Fred Gunther takes a different view of the buffing/detailing task. Gunther owns seven Grand Sport Auto Body shops in the West Chester, Pa., area. He believes consistent, quality work is best achieved through specialization, which is why there are nine detailers in his seven shops who do all the buffing. “The buffing step is an integral part of our quality-control process, and we think you get the best results from someone who does the same job over and over again every day,” he says.

Gunther also points out that this task has taken on more importance in recent years. “Ten years ago, you buffed everything flat,” he explains. “Now [the technician] must be able to identify the gloss on the car and match that texture, because customer awareness has increased tremendously.”

Jorge Medina appreciates the importance of buffing. He’s been doing it for nine years, the last six of which he’s spent at the Keenan Auto Body Center in Clifton Heights, Pa. One characteristic of a good buffer/detailer, Medina believes, is patience. “Don’t sand the car right away, even if it feels dry,” he says. He advises waiting one or two hours, when most clears are cured enough for buffing. “You can smell when it’s dry,” he claims. Which makes sense: If you can smell the finish, it usually means the solvents are continuing to evaporate.

Wait—but not too long

Buffing too soon will cause the finish to dull back as evaporation continues, advises Jerry Goodson, instructional designer with I-CAR. “On the other hand,” Goodson adds, “don’t wait too long. With some urethane clears, they have to be buffed within a day or two or they will totally lock down and become very difficult to buff.” 

In fact, some low-VOC clears that must be used in parts of California will turn rock-hard in six hours or so. The even newer mar-resistant ceramic clears now on some DaimlerChrysler vehicles present an even harder surface.

Most detailers err on the side of impatience, however. And waiting for full cure is the only way to avoid the dreaded swirl marks, according to Medina. “The last thing you want to see are swirls. You have to be especially careful with black. It really shows swirls.” If the paint isn’t dry, the technician also runs the danger of “burning” the soft edges of the paint.

The other major mistake Medina has noticed also relates to patience. “They run the buffer too fast, especially when they start the job,” he says.

Medina takes pride in his work, and his procedures demonstrate that pride. He starts with a soft pad on a DA polisher at 1,200 rpm. Then he uses a wet pad at up to 3,000 rpm to bring up the gloss. (Note: Only technicians with vast buffing experience should go to this high rpm range.) He buffs with a wool pad and then a polishing pad to remove all the swirl marks. Finally, he washes and hand waxes the vehicle.

He also notes that while a skilled detailer can buff out small runs, he needs to know his limits. If it’s a big run, says Medina, the car should go back in the booth.

An effective tool

Used correctly by a skilled technician such as Medina, a buffer/polisher is one of the most effective and versatile tools in the auto body repair shop. In the hands of a professional, it can eliminate myriad flaws in the finish and produce a new car shine that will impress the most demanding customer.

Basically, the purpose of buffing is to remove surface imperfections such as runs, sags and dirt particles, and match the surface texture of the repaired part to the rest of the vehicle.

The buffing step has been aided by many developments in the past decade, according to Goodson. He ticks off three such developments: “Foam pads have gone a long way in helping technicians eliminate swirl marks caused by wool pads. Buffers are now equipped with rheostats for rpm control. You can simply set the speed you want, instead of controlling it through the trigger. And microfiber cloths are great for hand detailing and eliminating tiny scratches in the finish.”

Other than avoiding burning soft edges, there are some basic procedures and precautions technicians should observe when buffing. First, before picking up the buffer, inspect the repair area for tiny dirt nibs and level of orange peel, as well as more obvious surface flaws. Then make sure the pad is clean. A foam pad can be cleaned with a stiff-bristled brush. A wool pad is cleaned with a spur. A wool pad should be cleaned whether it’s been used or not, because cleaning a new wool pad reduces a lot of the lint flyoff. There are pad washers on the market that are very efficient. The pad stays on the buffer, and the lid of the washer is closed over the pad. This keeps the cleaning solution and the fly-off lint from the pad contained.

Now you’re ready to begin:

  • Buff “off” the edge of a panel or body line, not “into” it.
  • Keep the speed slow and keep moving.
  • Use light to medium pressure and never more than necessary.
  • Keep the polish on the surface. Don’t let it dry completely.
  • Buff in small areas—no more than two square feet. Don’t try to do a complete hood all at once.
  • When making a repair, remove as little of the paint as possible—just enough to correct the condition. Generally, car manufacturers require a color thickness of .3 to .5 mil, and warranties require at least 1.8 mils of clear. Buffing operations should not remove more than .2 mil (.002 inches) from the complete paint system. Suggests Goodson: “Sand a little, polish a little, but don’t go too far. You can’t put it back once you take it off.”
  • If you must use compound, make sure to use the correct cutting material for the size of the scratch. Some beginners use an abrasive that’s too coarse, thinking they’ll get the job done faster.

When you decide to polish, make sure to use the right glazing product for your paint. An addendum to this point is to avoid using glazing to fill scratches. Buff the scratches off; don’t use glazing. One industry expert has observed this procedure, and he says it looks fine until the car is washed. Then the glaze washes off, revealing the scratches.

A few words about buffing technique. Regarding safety: Wear vinyl gloves so you won’t get fingerprints on the surface. Also, some buffing products contain silica, a known carcinogen, so check the material safety data sheets to make sure you’re wearing the proper respiratory protection. A NIOSH-approved particle respirator, or at least an approved dust mask, is required. And always wear safety glasses. That goes for virtually any refinishing procedure.

Three application methods

There are three different methods of applying the buffing material. One way is to apply the material to the panel, then smear it over the panel with the buffing pad before turning the buffer on.

Another way is to apply the buffing material in stripes, then pull the material into the pad in one motion by starting the buffer, tipping it up slightly and sweeping over one stripe at a time in a counterclockwise, or right-to-left, direction. This direction prevents the material from splattering. This first sweeping-in action is quick. Then the buffing travel speed should be slowed down.

The third way is to apply the material directly to the pad.

No matter which method you use, be sure to use sufficient compound or polish to allow enough wet buffing time. In the words of one expert, “Wet it out. You want almost a slurry product, so that you have continuous wet foam.”

To keep the cord out of the way when buffing, hang it over your shoulder.

“Start slow,” advises Goodson, “and be patient. Stay within a one-to-one-and-a-half square foot area.” Experts also recommend overlapping 50 percent with each stroke.

Buff away from raised body lines, not into the raised area. This prevents the buffer from burning the raised area. You can do that section by hand later. 

Except in tight areas and when changing directions, generally keep the buffer as flat as possible.

Before moving to the next area, stop and clean the buffing pad. If you are switching materials, switch pads—when going from a compound to a polish, for example. And again, clean or replace the pad before starting.

Finally, use a film thickness gauge to measure the surface film and ensure that you haven’t removed too much clearcoat during the buffing procedure.

Basics for better buffing

Here’s a detailing checklist from Mike Levasseur, co-owner of Keenan Auto Body Centers in the Philadelphia area. Perhaps you can use it as a guideline for your own list. As the final note indicates, each job is different, so this is merely a guide.
  • Read the work order
  • Inspect the finish for defects (runs, direct, color match, etc.)
  • Sand if necessary (1,000 grit up to 2,000 grit)
  • Compound sanded areas completely to proper shine
  • Glaze with foam pad to eliminate swirl marks
  • Unmask vehicle completely
  • Buff adjacent panels for proper match
  • Wipe all excess compound and glaze from jambs
  • Blow out inside of vehicle, engine and luggage compartment
  • Wipe down upholstery (shampoo), dash, cup holders and trim
  • Wash vehicle exterior and jambs
  • Clean wheels and tires
  • Dry vehicle
  • Re-inspect vehicle for any defects
  • Apply any adhesive moldings, trim, stripes or ornaments
  • Hand glaze as necessary
  • Use touch up paint on nicks and scratches as a courtesy; touch up bolts
  • Rubber and vinyl dress as necessary

All vehicles and repairs are different. Use your best judgment. If anything seems unusual, consult with your supervisor.

About the Author

Bob Yearick

Bob Yearick recently retired from the DuPont Company after 34 years of service. He was editor of DuPont Refinisher News for nearly 20 years.

Sponsored Recommendations

Best Body Shop and the 360-Degree-Concept

Spanesi ‘360-Degree-Concept’ Enables Kansas Body Shop to Complete High-Quality Repairs

ADAS Applications: What They Are & What They Do

Learn how ADAS utilizes sensors such as radar, sonar, lidar and cameras to perceive the world around the vehicle, and either provide critical information to the driver or take...

Banking on Bigger Profits with a Heavy-Duty Truck Paint Booth

The addition of a heavy-duty paint booth for oversized trucks & vehicles can open the door to new or expanded service opportunities.

Boosting Your Shop's Bottom Line with an Extended Height Paint Booths

Discover how the investment in an extended-height paint booth is a game-changer for most collision shops with this Free Guide.