Prepping a Car for Paint

Posted: December 18, 2015 By: Eastwood

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 do it yourself, and see if you can’t knock a couple hundred 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 for painting. 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.


Wash the Car


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, finger prints and what have you. These things can cause “fish eye” among other paint issues if not cleaned off beforehand.

Before actually washing the car make sure you roll it outside and get all the dust out with a blow gun attached to an air compressor. Sanding dust likes to hide in corners and cracks where you wont even see.  It 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.

Just wash it like you normally would wash a car, but make sure to use soapy water and wash off any grease, engine oil, and the oily residue from your fingers. 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 solvent. 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


Scuffing for Adhesion


Now the time has come to start in on the labor intensive sanding. 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.  You will also get a lot of different recommendations of what grit sandpaper to start with; everything from 400 to 1200 grit sand paper. 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 sand (dunking the sandpaper in a bucket of water frequently) and the job will go faster and easier, and you will use less sandpaper. Wipe down once again with PRE the sanding is done.


Prime Time


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 primer out there, so make sure to use a primer recommended for the surface you are stating 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 often times a coat of a primer sealer will be applied to avoid any possible chemical interactions between the old paint and the new.


Once the bare areas are covered, put 2-3 coats of primer over the whole car. Follow the direction for the primer as far as time between coats. Wet sand the primer, making sure to sand out any drips, scratches or other rough spots with 800-1200 grit sand paper. Wipe the car down again with solvent and a clean rag, 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, paint within an hour of priming, or after 24 hours drying time.


Ready, Steady, Paint


Now you are ready. It’s time to drop off your project with the pros at the body shop for paint. Or, 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.


Prepping isn’t rocket science, and if you have the inclination and the time to spare, you can learn to do a good job in no time. Remember its 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 proper planning will almost guarantee amazing results.  Of course paint work like this wont come to you over night but everyone needs to start somewhere.  Eastwood has all the painting information you need to start painting in your own garage.


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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One thought on Prepping a Car for Paint

  • I have a feeling that trying to paint your car yourself would result in… less than optimal results.

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