The prep stages that a car is put through before being painted must be methodically and precisely followed to get pro results. How to prep a car for paint is time consuming but rewarding.
Spray painting any automobile for whatever purpose, touch up, fixing it after an accident or a whole new paint job, is an art.
How to Prep a Car for Spray Painting
First, look over your cars finish and find any imperfections, rust, etc. and repair those areas. Look at your vehicle from all angles and in different lighting. The devil is in the details here, so take your time when spotting trouble areas. Here are the general steps you should take to get your car prepped for spray painting.
- Masking and taping
- Sanding or cutting
- Cleaning your work area
Masking and Taping
The first step to follow in prepping your car for paint would be to take time to mask and tape any areas that you don’t want affected by overspray. These areas include windows, windshield, headlights, taillights and any other areas of your vehicle you aren’t spraying.
You can mask your car with plastic sheeting or newspaper. This will protect those areas from overspray or accidental spray.
During this step, if any areas that you’re spraying are located near areas that shouldn’t be sprayed, these can either be masked and taped or removed. For instance, if you’re retouching a scratch on your door, you should tape up the window, side mirror and the handle to protect them from overspray.
Once done with the painting and the finishing, these parts are all unmasked or re-installed.
How to Take the Paint Off a Car
When prepping a car for paint, we recommend removing the old layer of paint. Down to bare metal is ideal for best results and bonding of your primer to your surface. Patience is key here because getting larger areas like panels and doors down to bare metal takes a bit of time.
The best 2 ways to remove paint off of your car, is by sanding (by hand or with an orbital sander) or using chemical paint strippers to take of the paint which is called "cutting".
What Will Take Paint Off a Car?
So, how do you prep a car for paint? There are two main options for prepping the surface of your car and removing old paint: Sanding or Cutting.
Sanding involves using elbow grease or a power sander and different grits of sandpaper depending on the stage you're at and what you’re sanding (old paint, primer, etc).
Cutting is when you use a chemical stripper to help remove old paint from your vehicle. Simply apply it with a cloth and watch the paint peel away. It is recommended to use these chemicals safely, so make sure you are wearing all the needed protective gear including a paint respirator.
How Long does it Take to Prep a Car for Paint?
Just prepping your car for paint (masking, taping, sanding/cutting and removing car parts etc.), checking for damage and repairing body work (if required) is time consuming. Sanding each panel properly can take up to 2 hours. Prepping your car for paint can take up to 20 hours, not including the actually priming and painting.
The next step after masking and taping, is to prepare the surface, or surfaces, of your car for painting. Prepping the surface of your vehicle is all about sanding or stripping the surface until the existing paint is removed.
If it’s a small area you need to prep, you can prep the surface by hand. Getting down to bare metal is the best option here. Make sure to get into all the crevices and corners that you need to spray.
You can use a power sander, but these are used mostly for bigger jobs like prepping an entire panel.
Power sanders speed up the process a ton but plan your project wisely. You will need to invest some time into your sanding: 1 panel can take up to 2 hours. If all you plan on spraying is small repairs, then you don’t need a power sander, but be prepared to invest a lot of elbow grease instead.
When you’re sanding your car, you’re improving the surface’s ability to grab and hold the primer and paint so that no defects appear once the paint has settled. A properly sanded and prepped surface means you’ll get a smooth consistent paint result. Defects include bubbles that might form in the paint because of a dirty surface, or the paint can flake if the surface isn’t smooth.
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What Grit of Sandpaper is Used to Prep a Car for Paint
You’re going to need to grab a few different grits of sandpaper for prepping your car for paint.
To strip the paint down to bare metal, we recommend you use 1200-grit sand paper or sander pads. Using anything finer and you won’t achieve the ideal level of prep on your surface to ensure paint adhesion.
To remove only the gloss or clear layer or for general sanding, you can use anything that is super fine and we recommend between a 2000-2500-grit.
Cutting: How to Strip Paint from/off a Car
Another option to prep your car for paint is to use paint stripping chemicals. This is called cutting.
Cutting uses an abrasive compound that is applied to the surface by hand or an orbital polisher. It can remove thin layers of paint or can be used to blend two paint jobs into each other after spraying.
It’s always good to follow the exact instructions before working with the cutting compound, as it can get into everything, especially when applied by a power tool.
There are different formulations for removing specific types of paint, so be sure to purchase the correct cutting compound; if unsure, consult the manufacturer of the paint you’re trying to remove. Using a clean, dry cloth, apply the compound to the surface in a smooth circular motion.
If the area to be painted is too big or the whole body is being resprayed, we recommend using the power of an orbital polisher. You should note that it requires practice and diligence to master cutting. Keep at it, and you will perform like a pro in no time. Focus on keeping the compound moving, spreading evenly.
Spending too much time in a specified area could lead to an uneven surface. To make your life easier, you can spray the area with water to keep it cool and the compound easy to spread.
Cleaning Your Work Area
It’s important to make sure that your work/painting area is completely clean before you start painting. You have to eliminate everything that might contaminate your paint or primer.
Proper ventilation in your spray booth or work area should remove most of the airborne contaminants but you should still do a thorough check and remove all dust from your working area.
Can You Paint Over Existing Auto Paint?
To try and save a lot of effort and time, you might be tempted to paint over your the existing paint on your car to eliminate the prep steps. Do you HAVE to remove old paint before repainting a car?
It’s possible to spray over existing auto paint finishes, but we don’t recommend it. When it comes to prepping a car for spray painting, particularly when the surface has been damaged, or the old paint is peeling, or worse, the paint has to be removed completely.
Removing the old paint and starting fresh with bare metal and primer will give you the best results.
How to Sand a Car for Primer
Deciding which of these methods, sanding or cutting, that you want to use is mostly up to you. The best way to sand a car for primer and paint is up to each individual painter. We recommend using a power sander to speed up the process.
Primers make sure that your paint bonds properly to your car and helps to ensure a smooth consistent surface. Colors are richer and your paint job will last longer if you prime your car before painting.
For best results on your car paint job, sanding and priming is so important.
Best Way To Remove Car Paint to Bare Metal
If you need to completely remove the paint from your panel, door etc., you will no doubt be looking for the best and fastest way to get down to bare metal.
Some reasons for preparing the car this extensively could include rust forming below the paint, or peeling from saltwater damage in coastal regions or damage from road salt in colder climates. To strip the paint off of the body down to bare metal, you can sand with an orbital sander until all the paint is removed, or use a stronger compound when cutting.
Our recommended method of getting your car down to bare metal is using a power sander.
How to Sand a Car Fast
To take the paint off a car quickly, we recommended to use an orbital sander. Pros have access to industrial sand blasting machines that crush sanding a car in way less time than At home DIYers.
We found a local business where you can rent out their sand blasting booth by the hour. For the fastest sanding check out your local business directory and see if there’s a shop like this in your town. For the rest of us, power sanders are the fastest way to get your car down to bare metal.
Sanding is one of the most important processes of prepping a car for spray painting, and it’s worth it to spend time and use the correct method for the best results.
Don’t think that you will master it overnight, but once you have it down, it will seem simple enough. You will need to use different grades of sanding paper for each specific job.
When sanding, do it in circular motions over your panel or area for the best results. If using an orbital sander, make sure that you move it in a circular motion with consistent pressure. This ensures that you take the same amount of paint off from each area that you’re prepping. You don’t want to end up sanding too much in one spot and creating dips and uneven areas on your car. Bummer.
If spraying your entire car, then move slowly over one to two feet of surface at a time, resting the machine in between.
Excessive dust will become a problem and can be harmful; wear the required safety gear for protection like goggles, gloves, and a respirator. With each pass of the sander’s motion, you should see the paint stripping from the surface, continue until all the gloss and seams have been sanded away, and the surface is bare and scuffed enough to be painted.
Run your hand over the area to double check for dips, bumps and uneven surfaces.
Practice Makes Perfect
Double-check your work, and if you find any spots that need attention, touch them up with your sander. It’s important to be sure that each surface is scuffed evenly and properly. Once the sanding is finished, it’s ready for priming.
Prepping a car for paint isn’t as hard as you think it is. While it is time consuming, our guide above along with one of our recommended best paint sprayers for cars will lead to pro results.