Dings from car doors. Imprints from shopping carts. Dips from hail storms. Although aggravating to motorists, small cosmetic blemishes such as these can be repaired in a matter of minutes. Using a concept known as paintless dent removal (PDR), technicians access the area behind the dent and massage the metal back into place.
Dents--from the size of a dime to 2 or 3 inches in diameter and larger--disappear in a span of five to 15 minutes. In many cases, there is no evidence a dent ever existed. In other instances, only a small black plug in a door end indicates PDR was necessary.
PDR professionals say it's the least invasive way to repair a dent. Others say it doesn't compromise the vehicle as traditional repairs may. And for vehicles with custom paint jobs, PDR is often the only way to retain the design. Ten to 15 vehicles can be healed per day at the hands of an experienced technician.
Collision shops benefit from PDR by outsourcing small projects to these mobile businesses or by offering PDR as an additional service--a facility repairing a vehicle can efficiently and cost-effectively repair dents that may not be part of the original work order.
Not Always the Solution
Even though PDR can erase many offensive impressions, a number of factors restrict the technique. Limits vary among individuals, whose experiences shape opinions about which dings can be repaired.
Despite the lack of standardized guidelines, consider these factors:
* The size of a dent. Some individuals repair dents the size of dimes and quarters. Others repair much larger dings. An underlying concern is how much the vehicle's metal was stretched on impact. Pushing on overly stretched metal can further distort it and can lead to paint problems. Because of the weight of hail, repairs should be held to damaged areas less than 2 to 3 inches in diameter.
* The brittleness of the coating. Paint that is brittle may crack during the PDR process. Some vehicles' coatings take years to reach a brittle stage, while other paints emerge that way from the factory. If brittleness is a problem, warming a dented area with a heat gun is said to prevent cracking.
* Access limitations. Although nearly all dings can be reached, it isn't always worth it. Attempting to fix a small dent that is difficult to reach is more feasible than trying to repair a large damaged area that is hard to access. The finished results may not be satisfactory in the latter instance.
Learning the Technique
While dents, dings and creases vanish in a matter of minutes at the hands of a PDR technician, developing such skills is not an overnight feat. It takes about one month to learn the basics, but six to 12 months of continued training, observation and practice are usually necessary to prepare for solo work.
The characteristics of various vehicles' metals as well as the location of components inside doors are essential bits of knowledge--drilling an access hole through a window or a power lock motor does not satisfy customers. Learning how and which tools to use also requires time. These tools must then be directed to the wound and used to gauge the pressure necessary to restore the vehicle's original appearance.
Tools of the Trade
Tools serve one primary function: to provide access to the dents. A set of basic tools can cost $2,000, and investments of about $3,000 are required for more complete toolboxes. Most of the tools on the market share similar appearances--rods with multiple ends bent into various angles provide access to damaged panels.
To move beyond appearances and analyze a tool's value, determine whether it will access the necessary problem area; then, decide if it will be strong enough to push on the ding. Another necessity in the PDR toolbox is a fluorescent light or a reflective board. These show every wave, dent and mark on a vehicle's body. Use the light to observe the dents and to mark their progress. As the dings disappear, the light's reflection on the vehicle improves. With the light, the tool's path is also monitored.
Access the Dents
Before embarking on a paintless dent repair, verify that the technique will mend the vehicle. Severely gouged or chipped paint hinders the completeness of a job, as will metal that is too distorted.
Once feasibility is established, decide how to access the dent. Find the fastest and least intrusive route to the area behind the damage. Hoods and trunks are more open than doors, fenders and quarter panels. But repairing the hood or trunk often requires removal of noise dampening pads or carpeting and working through a brace. For front-end and rear-end damage, pull headlight and taillight assemblies to open access for PDR tools. Roof work entails dropping the headliner. Some technicians even remove the windshield when there is a lot of roof damage, such as from a hail storm.
When no obvious route exists, many PDR technicians drill small access holes in places such as wheel wells and door ends. Some shun this practice, while others insist that it's necessary. Holes are drilled to standard sizes of 1/4-, 3/8-, 1/2- and 3/4-in. and are plugged when the project is completed.
Under the Hood
The first step in hood work is to remove the noise dampening pad or to cut out a piece of the pad to access the dent. Then determine if a brace blocks the path to the damage. If so, examine the brace for existing holes or passageways. When no factory access path exists, the remaining option is to pierce the bonding caulk between the hood and the brace using a thin, double-edged blade. Run the blade along the upper and lower sides of the caulked area for a thorough break.
Next, secure the hood. One suggested way is to use an adjustable hood prop to establish optimum work height. Set the prop under the center of the hood and evenly space two bungee cords, 12 to 16 inches long, on each side of the prop. Tightly secure the bungee cords so no upward hood movement is possible. Now slide the selected dent removal tool through the brace, using the former obstacle to gain leverage.
Door Dings
If the damage is in the door panel, access is gained by going through water drain holes, wiring harness channels, reflectors and other holes made by the manufacturer. Removing the door panel is also a useful access method in some cases.
It is also possible to reach the damage by inserting the tool beside the window. For this, roll the window down and slide a piece of hard plastic next to the glass to protect it. Insert a wedge--like what is used when unlocking car doors--to open an access area about 1/2 in. wide. When applying pressure to the dent, be careful not to shatter the window.
When working with doors on unfamiliar or new vehicle models, slide a tool into the door parallel to the window and use the tool to gauge component location.
Fender Mender
Headlight and taillight assemblies provide access to fenders and quarter panels, but opening the trunk to reach taillight sockets may require the removal of some carpet. Another technique includes hanging an S-hook on the drain rail on the trunk's side and sliding a long tool through it to the quarter panel. Wheel wells offer another entrance alternative. Some have factory holes, while others require drilling. One method is to jack up the car and drill a hole in the splash guard.
Undoing the Damage
Once access is established, select the proper tool. Take into account the length, diameter and tip size when choosing.
Now the repair begins. The idea is to use repetitive movements to duplicate the pressure that caused the damage. By applying pressure over and over again, urge the metal and paint back into position and recreate the orange peel in the coating. It will take numerous soft pushes to reverse the damage because only a small amount of metal can be moved at a time.
Four types of damage require four plans of attack. Standard dents are reversed by massaging the center of the damage. To repair a crease, apply pressure to the center using a left to right motion. Double dings should be mended beginning with the smallest dent. Repair 90 percent of this damage, and then fix any distortion around the larger dent. Move on to repair the largest area and then return to the remaining 10 percent of the smaller ding. The bulk of teardrop-shaped damages should be repaired using the method for standard dents. The remainder is treated as a crease.
To start a repair, position the light perpendicular to the damage. Working at an angle creates an optical illusion and makes it more difficult to locate the tip of the tool, so stand perpendicular to the dent.
The next step is to locate the tip of the tool. As the tip moves along the back of the metal, it will be visible because of the light. To demonstrate this concept prior to working on a vehicle, use a piece of aluminum foil. Stretch the foil tightly, and run a fingernail along the underside, watching for an indentation. This same principle applies to vehicles.
Once the tip of the tool is located, move it to the center of the damage. Apply pressure in short, steady efforts. Watch the light's reflection on the vehicle. It should improve as the metal straightens.
To remove the damage surrounding the center, mentally picture the dent as a circle. Imagine a line cutting the circle in half. Select one point on the perimeter, and place the tool there. Apply pressure and drag the tool from the perimeter toward the center of the circle--where the line should be crossing. Increase the pressure as the tool nears the center.
As the dent decreases in size, more force is required to continue the repair. When the damage is extremely small, maximum pressure is necessary. But this must only be exerted on the center of the dent. Applying pressure off center has a number of adverse results, including distorting the metal, creating a wavy appearance and forming a high point. If too severe, it can prevent a complete repair.
There is little room for error in a PDR job. Tools that slip can wrinkle metal or push the material outward, forming an unwanted high point. Wrinkled metal is difficult--if not impossible--to repair, depending on the force behind the slip.
High points sometimes can be pushed back using a dent hammer and a tool that resembles a plastic punch or an oversized pencil. To help prevent high points, wrap the rod tip with several layers of duct tape. This softens the tool's force on the area. Just remember to remove the tape toward the end of the repair to pinpoint the remainder of the damage.
Except for correcting high points, there is rarely a second chance in PDR. Traditional collision repair procedures are the only way to mend severe errors.
Finishing Touches
If an entrance hole was drilled, mend it once the dent removal is complete. Apply sealant around the hole to protect the paint from harmful weather elements. Select the proper sized plug--1/4-, 3/8-, 1/2- or 3/4-in.--and place it into the hole.
Now examine the paint. Wet sanding is sometimes necessary to smooth surface imperfections caused by the damaging object. The process also hides high points that resulted from the PDR work.
The only step remaining is to return the vehicle to its owner. Then, sit back and enjoy the satisfaction of easing the shop's small-job process--while also boosting your sales figures.
