I’ll admit I’m car proud, I recently returned to my Volvo to find some extra paint on my bumper. Truthfully, I lost my s@~* for a moment, what a waste of energy. So instead, I thought, I know, I’ll make lemonade.
So how do you remove scratches from a car bumper? First, wash the affected area with soapy water. Rub the scraped area with a compound cutting paste. Buff to remove the paste and using a paint stick, apply 2 coats of touch-up primer, 3 coats of paint, and one clear coat to the scrape.
All bumper scrapes aren’t the same, some are deep, some are fine light scratches, others may just have a black rub mark. I cover repairing all in this guide.
Wash The Scraped Car Bumper
Washing a car before rubbing a cloth on the paintwork prevents small grit particulars from scratching the paint.
Waxing without washing the paintwork causes those fine scratch swirls in the paint, most commonly seen in black paintwork. Rubbing the paintwork with a clay bar is the best way to prepare the paint surface refinishing, it gathers any grit from the surface.
Although household detergent does a good job cleaning a car, it’s too aggressive. It strips off the protective layers of wax, instead use proper car washing detergent.
Use A Compound Cutting Paste
Compound is an abrasive rubbing paste that’s designed to clean away layers of damaged paint. The reason for using it here is to clean down the scraped area and allow us to see the extent of the damage.
Often when a bumper is scraped, it will be a combination of rubber, from saying another car bumper, plus the other car bumper paint, and in addition, a paint penetrating scrape to your bumper paintwork.
The compound rubbing paste will clean away the rubber and foreign paint and will leave you with just the broken paint scratch.
Scratches often look much worse than they actually are but you’ll see that the rubbing compound will take most and sometimes all the rub scrape marks away.
I use Farecla rubbing paste, which I have been done for years. It comes in different grades, the real course pastes for extra cutting used for removing layers of heavily oxidized paint on older cars.
For car, bumper scratches the lighter white cutting paste is just the right balance of abrasive. Apply the paste in an up and down motion using a wet cloth, this creates a lubricant so the paste can be easily spread and improves its cutting performance.
As the paste starts to dry, apply more water, I use a spray bottle to allow greater control over quantity.
You’ll notice some if not all the rub marks come off the bumper. A soft cloth is best to remove the paste. Buff the area, so all the paste is removed.
The alternative to hand rubbing is an orbital buffing machine. These aren’t very expensive and are not necessary for just a scrape.
But if you’re tempted to do complete paintwork deep cleanse by hand, be warned, it’s a labor-intensive job.
A buffing machine will leave a superior finish in about half the time and it’s a real pleasure to use. I’m buffing cars for about twenty years and the before and after transformation still amazes me.
Using A Touch-Up Paint Stick
If you have broken paint, you’ll need a primer, color match paint stick, and a clear coat.
I use a touch-up stick kit that includes all three, you’ll get a kit specifically for your vehicle color.
We begin with primer, its function is to fill the deep crack of the scratch and to help the paint stick to the bumper.
I apply two to three coats, depending on how deep the scratch is. Fill just the crack of the scratch and not too far outside it.
The primer will require about 20-30 minutes between coats and if the temperatures are low, postpone to a warmer day or move to a heated garage.
Sanding The Primer
Now I understand some people might not want to go to this extent and that’s OK. Your scratch may be very low down on the bumper, it won’t be noticed that it’s deep. If that’s the case, go ahead to the painting stage.
When the crack has been filled by the primer, allow an hour to harden. I use a small sanding block with 600 grit paper to flatten the primer out, use some soapy water to help lubricate the sanding block.
Try using a cloth or a newspaper that works great, now examine the crack, if the primer has sunk into the crack, you can apply more primer and repeat this process. The better the primer fills the crack, the better the finish.
If you do choose to block flatten the primer, use the white paste to bring the surrounding paintwork back to life.
When you’re happy with the primer results and the area is clean and dry, prepare your paint by shaking your stick vigorously.
Avoid applying paint in damp conditions, it will trap moisture in the paint and cause a cloudy finish.
Applying The Paint
The paint stick can sometimes be a little big for the job at hand, if so, trim it at an angle, you’ll have greater control.
Pro-tip, I use a selection of artists’ brushes for touch-up, the bristles are far better quality and you’ll have real control of the paint flow. I don’t usually use the brush applicator.
Apply one thin coat of paint, cover the primed area and just outside it. Repeat this for three coats, allow 15 minutes between coats.
The paint will need several hours to harden and that will vary depending on your weather conditions and how much paint you’ve applied.
I like to use 1200 grit paper and soapy water to block sand the paint to smooth out any imperfections, a light rub does the job.
We’ll need to use the cutting paste once again to bring the paint back to life after the 1200 grit paper block flattening.
As with the block sanding of the primer this stage may be skipped if you are happy enough with the results, you can move straight to clear coating.
Applying The Clear Coat
As with the paint, the clear coat stick needs to be shaken vigorously for a couple of minutes. The bumper needs to be clean and really dry
The same rules apply to the clear coat brush, if it’s too big, cut it to suit. Don’t be tempted to use the paint stick brush on the clear coat without first cleaning it.
Apply two even thin coats of clear coat and allow 15 minutes between coats, after one-hour drying, you’re ready for polish.
Polishing & Waxing
Now comes the polish, but not all polish is the same. Polish is traditionally used to clean the paint surface, not protect it. For protection we use car wax, the very best is Carnauba wax also known as palm wax.
Some polish formulations are a cross between polish and wax, they clean the surface and protect it. If your car has a few years on it, then the paint will have fine swirl scratches.
Can’t really be helped, comes from everyday use, dust, flying debris, car washing.
I use a special polish & wax formulated for this type of damage. You pick the polish color the matches your car color, it’s not like an exact paint match, it’s more like in the ballpark.
The polish/wax is a rich creamy formulation with a color dye of your choice. This stuff works really well, the polish/wax and dye fill the micro swirls and make them invisible, it also protects and shines the paintwork.
Apply and remove the formulation with a soft microfiber cloth, or if you’re using a buffer use a lambswool head or equivalent.
Like all wax, it won’t last forever, but if you used it once a month, your paintwork will be in great shape.
If your paintwork is faded, check out this article, it deals with red faded paint but really it works on all colors “Restore faded red car paint”.
How to fix a hole in a plastic bumper? A Fiberglas repair kit is the best repair solution for a hole in a plastic bumper. The kit comprises Fibreglass sheets, resin plus activator.
- The Fiberglas sheet is placed on the inside of the bumper, over the hole.
- The resin and activator are mixed together and painted onto the Fiberglas sheet.
- Within minutes the sheet is hard and can be sanded and painted.
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.