a worker sanding a car for painting

How to Sand a Car Before Painting

You might have done some painting in the past; like painting a wall, painting wooden furniture or even your ceiling.

Well, great! It is quite a different thing for you to paint a car and that is why you need a handful of guidelines on how to sand a car before painting. It is arguably the most crucial stage of the repainting process.

The first thing you need is time; you need to create time for it. As for materials, you will need 1,200 – 2,000 grit wet-and-dry sandpaper or an excellent sanding machine, abrasion-resistant film.  You will also need abrasive discs if you are using a sanding machine.

So let’s quickly move into the process proper:

What Is Sanding?

Simply put…

…Sanding is one of the most critical aspects of paint preparation for a car, and it helps to remove the top layer of a car’s paint with the use of abrasive materials.

It’s important to invest all the time to do it properly to get the best possible results. Sanding can be done with either an electric orbital sander (like ) or sandpaper, depending on the job, and you’ll also need to use different paper grades depending on the task.

How to Sand a Car Before Painting

a worker sanding a car for painting
auto mechanic worker applying washing car body preparing for painting at automobile repair and renew service station

1. Preparation of the Surface

Before you begin the sanding process, you should start by removing any obstacle, as they will only make the job harder. By obstacles, I mean any dust, grease, or road grime. Of course, this can be quickly done by washing the car.

Also take off any loose fittings on the car’s body or any attachments like the side mirrors, headlight covers, and the badges. In short, remove all that can be removed. Everything else should be masked with the abrasion-resistant film.

2. Fix the Dents and Scratches

The next thing to do is that you should take care of any visible dents or scratches (whether deep or just a slight one). If you are going to make use of a filter, be sure that you get excellent adhesion.

This can be done easily by cleaning the inner part of the dent, the scratch or the chip (if present), which creates a rough surface, of course with the use of the abrasive.

3. Get the Sanding Machine Ready

sanding car before painting

Now that the car’s exterior is all prepped up, you can now attach the coarse abrasive disc onto the sanding machine. You can use the P60 grade for the first sanding process.

Do not get carried away by the sound the sanding machine produces; there is a pattern you must follow. You should not just use it anyhow.

You should start by using a smooth circular motion to remove the clearcoat, the topcoat, and the base coat completely. When sanding using the smooth circular motion, do not stop and also do not move too fast.

For you to reach the corners of the car’s body parts correctly, you would have to sand with your hand using sandpaper (watch the video below). If the coarse attachment cutting is turning out to be too hard, change to a lower grade.

For you to get the best result, sand the entire body till you get a perfectly smooth surface for the primer to adhere to.

It will take more time if you are using sandpaper, but make sure that you sand the entire surface as smooth and even as you possibly can.

4. Change the Abrasive Disc

Once you sand to the point where you get to the primer, change the coarse disc you started with and switch to one with the more delicate surface.

The essence of this is to completely get rid of the scratches that must have resulted from the initial sanding with the coarse disc.

Ideally, you must get to the bare metal, so you should continue to remove the primer as much as possible.

5. Finish it up!

One of the importance and purpose of the whole sanding process does not only make the surface of the car’s surface free from unwanted particles, but it is also to make the surface ready to have enough grip for the primer and the paint.

As a quick reminder, the best practice on how to sand a car before painting it is to remove the former paint and primer to get down the bare metal.

This will make ensure the finish is more even and provide a stronger and more durable adhesion when the new primer and paint are applied.

Finally, you are doing this indoors, make sure the floor is adequately swept, and there is enough space for you to work. Avoid any form of obstacles.

And if you are working outside, do it where there are not too many dust particles or other contaminants. And now, your car’s body is ready to get painted.

Watch the short video below for a better understanding of the process of sanding a car before painting:

Do you wet sand a car before painting?

Whether you’re talking about paint, primer, bare metal or anything in between, your car’s body can be smoothed by wet sanding. Wet sanding, also known as color sanding, adds shine to a finished paint job.

What grit sandpaper do you use to wet sand a car?

Jason recommends beginning with 1,000-grit sandpaper. Coarser paper works faster but you’ll eat up the time saved when it comes time to eliminate the sanding scratches. Finer paper, say 1,500, leaves finer sanding marks that are easier to remove but the job takes a lot longer.

What grit sandpaper should I use before painting car?

Dry sand using 180-grit sandpaper to remove rust or surface damage before moving on to a 320-grit paper to remove your previous 180-grit scratches. Whichever method that you decide, follow it up using 400- to 600-grit sandpaper to sand the paint to prep the existing paint surface for the new coatings to be applied.

Can I sand my car with an orbital sander?

An electric orbital sander is a great option for a beginner who needs a good tool to sand or polish their car. All you have to do is plug it in, and you’re good to go. Just keep in mind that the vibration that electric sanders give off can be unpleasant.

How long does it take to sand a car for paint?

You can separate the car into different panels: the doors, the roof, the hood, the trunk, the bumper, and the fender. In total, each panel will probably take about 2 hours to sand down completely. It might sound like a long time, but it’s totally worth it for a new, smooth paint job.

Should you sand old paint before repainting?

While sanding is not required for every paint project, rough spots on walls, whether they have been previously painted or not, need to be sanded before they are painted to ensure the paint goes on smoothly. For previously painted water-based paint, sand with a fine-grit sandpaper.

What happens if I don’t sand before painting?

If you don’t sand before painting you will likely end up with an uneven finish and a paint job that will likely end up peeling after a few months. You may also be able to see any lighter or darker patches of the book come through the paint which looks ugly and unprofessional.

What to do if you forgot to sand before painting?

Sand until everything is nice and smooth, checking for ridges or uneven parts. Wipe down the area well with a damp sponge, dry with a cloth and allow the area to dry. Then, you can prime and paint the patched areas. Be sure that the paint matches perfectly; otherwise, the repairs will look obvious.

What kind of sander is best for cars?

Electric sander for car bodywork- top 3 picks in the market

  • DEWALT Random Orbit Sander-5” (best budget unit)
  • Porter cable electric sander/polisher (6 inch)- best variable speed sander polisher combo.
  • Makita 5-Inch Random Orbit Sander BO5041K Kit – easiest to use.

Do I need to strip paint before painting car?

Either way, your first step before painting should be to use a metal-etching conditioner (i.e., Metal-prep), which also removes any minor surface rust, followed by a good etching primer. Don’t let stripped metal parts sit and rust. Don’t strip your car until you’re ready to do the rest of the job.

Sanding a Car Before Painting | Conclusion

Why should you hire a professional who would charge you exorbitantly for a job that is cheap and easy to do? Painting a car is not as hard you may have thought.

If you wish to learn how to sand a car before painting, this post is the complete information you need to help you achieve your desired goal.

Getting the necessary materials will be more cost-effective for you than trying to get a professional. Give it a try now and see how much you could save in the long run.