Prepping a Car for Paint

Whether you are planning on painting your car yourself or paying to have it done, it is essential that the prep is done right. For the most part, it is a time-consuming job consisting of mostly grunt work. There is not really that much to learn about prepping correctly. So learn how to prep a car for paint yourself and see if you can’t knock a couple hundred dollars off the labor bill for the next paint job at the body shop.

For the sake of this post, I’m not going to go into dent pulling, rust repair and body filler application. Those things really all happen before you start prep. So let’s pick up at the point where the body is all smooth, but there is a mixture of old paint, bare metal and body filler on it. We’ll go over each step of the process along with the tools and supplies needed to prepare a car for painting.

Step 1: Wash the Car

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Just like Mister Miyagi told Daniel, wash the car. Before applying any finish to the surface, first you need to clean off all the old dirt, wax, oil, grease, fingerprints and what have you. These things can cause “fish eye” among other paint issues if not cleaned off beforehand.

Before washing the car, make sure you roll it outside and get all the dust out. This can be done using a blow gun attached to an air compressor. Sanding dust likes to hide in corners and cracks where you won’t even see it. The car may look clean and dirt-free until you pull the trigger on your paint gun and see a cloud of dust, taking you back to square one.

Once you’ve removed the dust, wash it like you normally would wash a car. Be sure to use soapy water and wash off any grease and engine oil along with the oily residue from your fingers. We sell a variety of car washing supplies from such companies as Griot’s Garage and the Chemical Guys that will get the vehicle nice and clean.

After the soap and water scrubbing, and after the water has all dried, use a fresh rag and wipe the surface down again with a cleaning solvent to remove any residual grease or polish. Some people use mineral spirits, acetone, lacquer thinner or other cleaners, but Eastwood sells a formula called PRE Paint Prep specifically for this stage. Wipe the body down completely with a tack rag and let it dry. Eastwood even offers a 50 State Compliant version of Pre called Pre Green Paint Prep.

Step 2: Scuffing for Adhesion

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The next step in car painting preparation is more labor intensive. Sanding the old finish or bare metal to “scuff it up” will help the new primer and paint stick. There are all sorts of vibratory and other sanders that can quicken the job, but certain parts will always have to be sanded by hand due to the complex shapes of most cars. If this is your first major sanding job, we recommend you do it all by hand using a variety of sanding blocks. Just because the pros use a DA Sander to level filler it doesn’t mean you should, too — it takes a lot of practice to get an even finish with any kind of powered sander. If you do have some experience, you can utilize a power sander or the Eastwood Contour SCT® surface conditioning tool to abrase the finish.

You will also get a lot of different recommendations of what grit sandpaper to start with; everything from 400 to 1200 grit sandpaper. Generally, you would start with 400 grit if there is body filler or old paint to feather or 600-800 if you are just scuffing an overall good-but-faded original paint job. Wet sanding (dunking the sandpaper in a bucket of water frequently) will help the job go faster and easier, and you will use less sandpaper. Wipe down once again with PRE after the sanding is done.

Step 3: Prime Time

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Now you can shoot the first coat of primer. Start with any areas that have been sanded to bare metal and the areas with body filler. There are several varieties of automotive primer out there, including epoxy, urethane, self-etching and polyester primer. Use our video guide for assistance and ensure you use a primer recommended for the surface you are starting with. Bare metal typically needs at least one coat of self-etching primer but that type of primer is not recommended for use over body filler. When painting over old paint, a coat of a primer sealer will often be applied to avoid any possible chemical interactions between the old paint and the new.

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Once the bare areas are covered, put 2-3 coats of primer over the whole car. Follow the directions on the primer container as far as time between coats and drying time. When the final coat has dried, wet-sand the primer with 800-1200 grit sandpaper. Be sure to sand out any drips, scratches or other rough spots. Wipe the car down again with PRE solvent and a clean rag but be careful not to use too much, or it can wipe off the primer.

Before moving on to paint, check the primer instructions. Some have a window during which you shouldn’t paint. For instance, the instructions might recommend painting within an hour of priming or after 24 hours drying time. Others also have a time limit after which the paint won’t adhere as well to the primer. Schedule your project accordingly to hit these time windows.

Step 4: Ready, Steady, Paint

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Now you are ready. The automotive paint prep process is done and it’s time to drop off your project with the pros at the body shop for paint. Or maybe it’s time to tape off a home spray booth with plastic sheeting and a few ventilation fans and go for it yourself. Eastwood has a variety of high-quality consumer paint guns that perform near equally when compared to some pro models. The Concours LT can even run off a small home compressor without hurting performance.

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Car paint prepping isn’t rocket science, and if you have the inclination, you can learn to do a good job in a relatively short time. Remember, it’s your car, and chances are you’ll pay a lot closer attention to detail than the prep guy at the body shop who may see multiple cars a day.

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You’ll be amazed by what you can do in your own garage. Taking your time and doing proper planning will almost guarantee amazing results. Of course, paint work like you see here won’t come to you overnight, but everyone needs to start somewhere. Eastwood has all the painting information and supplies you need to start painting and doing car paint prep in your own garage. We back them with a 100% customer satisfaction guarantee and free lifetime tech support by phone, email or in a brick-and-mortar store.

Check out the Eastwood Blog and How-To Center for more tips and tricks to help you with all your automotive projects. If you have a recommendation for future articles or have a project you want explained, don’t hesitate to leave a comment.

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