Modern car coatings strongly resist scratching, fading and discoloration under ordinary circumstances, but the open road is a hazardous environment. Small stones fly at high speed after being kicked up by the tires of other vehicles, and even quiet parking lots carry the danger of accidental damage from metal shopping carts and car doors from nearby vehicles. Outdoor dust contains billions of hardened, microscopic particles that can gradually erode the factory sheen of even the sturdiest coating. Scratches and dings are unavoidable.
Fortunately, minor scratching often can be repaired at home with the right tools and supplies. The instructions in this guide will cover repairing the most common problems with damaged car coatings.
Car Paint Layers and How to Identify the Type of Car Scratch
A newly manufactured car typically sports many square yards of exposed steel surfaces. First, a special, neutral coat, known as primer, is applied to the car. After that, a color scheme chosen for that specific car is added – this layer is known as basecoat. Because the basecoat is optimized for beauty rather than durability, a hard, clear coating meant to protect the layer of colorants, the underlying primer and the innermost steel surfaces is added at the very end.
By design, this final layer, known as clearcoat, can sustain a certain amount of routine scratching and microscopic wear without suffering much more than aesthetic degradation, but overuse of abrasive polishes can wear away even the strongest material.
Repairing a scratch begins with identifying how deeply it has penetrated these multiple layers. The clear, permanent protective layer is the most critical. Industry experts commonly grade scratches by their depth.
- Level 1A scratching is the minimum damage to the surface of the clearcoat, and it closely resembles the fogging that much-used eyeglasses accumulate from repeated, unprotected contact with tabletops.
- Level 1B scratching is a somewhat more severe degree of damage to the clearcoat, possibly resulting from a hardened object such as a bicycle protrusion or metal tool scraping across the surface.
- Level 2 scratching goes beyond the clearcoat and often damages the basecoat as well, but the primer is still in tact.
- Level 3 scratching is severe enough to reach the primer layer, but the bare metal itself is still covered.
- Level 4 scratching is the worst sort of damage, reaching all the way to metal and exposing it to oxygen, moisture, road salt and other corrosive influences. Rust is virtually guaranteed with untreated level 4 scratching.
Tools and Materials for Fixing Car Scratches
The severity and extent of the scratch to be repaired bears heavily on the tools and materials required. However, the following items will address most coating damage likely to occur under ordinary circumstances. Truly extensive damage demands professional treatment and falls beyond the scope of this guide. In order to fix car scratches, you will need the following tools:
- Orbital buffer – can also be used for work other than automobile repairs
- Disposable buffer pads
- Disposable sanding pads
- Sheets of 1000-, 1500- and 2000-grit wet-or-dry sandpaper
- Rubber block – such as a cheap school eraser.
- Rubbing compound – strongly abrasive
- Polishing compound – weakly abrasive
- Automobile waxing treatment – optional but recommended
- Masking tape
- Disposable cloths – very clean rags or microfiber shop towels
- Degreasing solvent
- Spray bottle
- Soap – just about any kind of non-abrasive soap or detergent
- Water – the universal solvent and cleaning agent
Step-by-Step Guide to Removing Car Scratches
No matter how deep the scratch goes, the beginning of the process is the same: the area to be repaired should be thoroughly cleaned with soap and water and then dried with a cloth before proceeding further. A water-filled spray bottle will help considerably with removing fine grit. Nearby trim, such as chromed plastic, can be protected against accidental damage with a temporary application of masking tape.
Levels 1A and 1B Damage
Repairing superficial damage to the vehicle’s clear, outermost factory coating typically calls only for a few sessions of light buffing with polishing compound, a small amount of which should first be spread evenly over the buffer pad.
- Step One: Clean the area and apply a little bit of polishing compound onto the buffer pad.
- Step Two: Make sure the area is completely clean and start buffing. Each buffing session will remove a little of the original coating, so it’s best to keep buffing sessions short. Individual power-buffing sessions should run to ten seconds, and manual buffing sessions should end after a couple of dozen strokes.
- Step Three: After each session, clear the area of remnant compound with a clean, dry cloth to check on progress. Bearing down too hard or too long on any particular spot risks completely wearing away the original clear coating.
Tip: For deeper scratches in the factory-applied clear coating, start with the more abrasive rubbing compound until the deeper scratches have faded into the background and then finish up with polishing compound.
Finishing: When the scratch has receded into near invisibility, use the water-filled spray bottle and a clean cloth to completely remove any remaining buffing compound. After the area has completely dried, automobile wax may be applied to protect the newly smoothed patch.
Levels 2, 3 and 4 Damage
A scratch that reaches the colorant layer, the primer layer or even bare metal calls for replacing the missing primer or colorant.
- Step One: Begin by applying a degreasing solvent to remove oils and waxes, which can seriously disrupt the tight chemical bond needed for a durable repair.
- Step Two: If primer is missing, then apply new primer. Some minor slop-over from the actual scratch is to be expected. Let the replacement primer dry.
- Step Three: Once dry, use a rubber-block-backed patch of 1000-grit sandpaper to carefully wet-sand excess primer until it matches the normal level of the factory primer layer. Peeking frequently at progress helps to avoid over-sanding and unnecessary removal of original coating material.
- Important: Neglecting to replace missing primer likely will result in poor colorant adhesion and a significant risk of hidden rust.
- Step Four: After any missing primer has been replaced, it’s time to add the replacement body. The procedure is the same as for the primer, but degreasing is not needed if the area is still clean and dry.
- Step Five: Apply rubbing compound as recommended for level 1B damage and then stand back for a moment to see how the affected area looks from different angles. If the replacement paint seems sunken, try again with a little more paint, and repeat the level 1B procedure.
- Step Six: Once the scratched area appears reasonably even and the last bout of buffing is finished, let the fresh paint cure overnight or longer within a protected environment such as an indoor garage. Wait a few weeks for remnant solvents to evaporate before waxing the affected surfaces.
Applying Replacement Clear Coating
Factory-applied coatings have relied heavily on applications of catalyzed enamel for outstanding durability and resistance to scratching. Catalyzed enamel doesn’t dry as regular spray coating; it’s artificially hardened with chemicals. A deeply scratched area, such as from levels 2, 3 and 4 of damage, almost certainly will need replacement clear coating after the first stage of repair.
Applying catalyzed enamel at home is not possible, as the methods of application require professional tools that are unavailable outside factory settings. Home repairers must rely instead on spray cans of lacquer that have been specially designed for automobile repairs. The lacquer dries by means of evaporation and are safer to use at home. Here’s how to apply the clear coat:
- Step One: If necessary, degrease the affected areas with an appropriate solvent. If a newly repainted area has not been subsequently exposed to oils or waxes, this step may be skipped.
- Step Two: Use strategically placed strips of masking tape or a large sheet of thick paper with a hole cut into it to protect surrounding areas from unneeded spray coating.
- Step Three: Lightly spray the area to be recoated, holding the spray can at least six inches away to avoid puddling and dripping.
- Step Four: Use a rubber-block-backed patch of 1000-grit sandpaper to gently remove excess material and bring the replacement coating to the same level as the surrounding surface. Paying insufficient attention to this step may result in an annoying and unsightly patch of clear coating that sprawls above the originally scratched area.
- Step Five: Let each coat dry for at least 24 hours before adding another. A grand total of three coats will suffice for durability.
- Important: As before, subsequent applications of automobile wax are best left until all remnant solvents have evaporated, which may take up to four weeks.
Finding the Right Replacement Color
Replicating a vehicle’s original factory color doesn’t have to be the sort of pounding headache experienced by house painters facing unique color schemes. Most currently operating vehicles have the factory paint code on an external sticker somewhere on the body or on a metal plaque hidden under the engine compartment hood or inside a doorsill. Should you not find the code there, most local car-paint dealers and many online paint stores have accumulated considerable experience with manufacturing custom mixes that closely match a desired result.
Detailing the Coat: Preservation versus Correction
Needless to say, avoiding accumulated coating damage with careful preservation techniques beats fixing what’s been broken by cruder correction techniques. A cautious vehicle owner minimizes gradual fogging and dulling by paying attention to regular smoothing polishes with finishing glazes, which fill in fine scratches and reduce optical distortions from reflected light.
Hand polishing can be a relaxing exercise, but a fair number of car owners prefer to use an inexpensive orbital buffer that finishes the job quickly. Gentler treatments of this sort avoid the erosion of the original factory coatings that results from too forceful polishing with high-speed rotary-buffing machines.
Vintage cars in particular decline substantially in value if they must be entirely repainted after years of rough polishing. Regardless of the collectible value of a car, harsher corrective techniques are best reserved for deep scratches that demand stern measures.
Today, vehicle owners have easy access to a full toolkit for fighting scratching, fogging and dulling that inevitably results from driving freely through a risk-filled world. With a little effort, any car can remain bright and attractive over many years of operation. The straightforward techniques offered by this guide do little justice to the imaginative techniques that tens of thousands of enthusiastic car owners have devised for preserving their babies against the ravages of time.
Have you ever fixed a scratch on your car?
Do you polish regularly?
What tools did you use?
Please share your experiences and thoughts on tackling car scratches with various tools and approaches!