Knowing how to properly prepare a car for paint is one of the biggest and most important steps to enjoying a great looking paint job. Whether you are installing new body panels or a body kit, or simply doing some of your own repair and restoration work, before you take your car in for paint you need to take the proper steps to prepare it.
Professional auto body painters always say that 90 percent of painting a car or truck is prep work, while the last 10 percent is actually spraying the car. This is why so many people outsource or simply pay someone that knows how to prep car for paint.
This guide exists to help you prep your car so that you can get the best quality paint job possible. This guide already assumes you know the basics, but in case you forgot them check below.
- Remove all emblems and stickers
- Wash car completely
Why do I want to prep my own car for paint?
Painting your car isn’t exactly cheap and if you want to save money on the lowest price paint job but still have high quality, prepping your own car is the best way to do it. There are lots of paint shops that will simply spray your car for a relatively low price.
Buy your own paint or simply pick the paint that the shop has available, but either way you can get really good results when you know how to prep car for paint.
Inspect your Car
Once your car has been cleaned, carefully inspect the body for any imperfections or dents that may need to be addressed. Scratches and holes can be repaired using filler, but you want your sheet metal to be as perfect as humanly possible.
Running your hand along the bodylines of your car can help identify where you might need some attention. Because you want the sheet metal to be as smooth and extensively cleaned and sanded for an excellent paint job. When someone doesn’t prep a car for paint correctly, it will lead to an uneven finish and dull shine.
You can go about it one of two ways here depending on what you want out of your paint job. If you have an existing coat of paint that’s decent and just want to freshen your car up, using a scuff pad is okay for many jobs. However if you are building a car meant for the show circuit or you just want the best paint job possible, you can also sand down to the bare metal.
This will really depend on how old your car is, and how many previous layers or coats of paint already exist. If it’s your first time painting your car, you usually do not need to go down to the metal.
Regardless of which method you choose, the reality is you want your car to have the best possible surface for the high-build primer to adhere to. Without the proper prep work, your new paint job could peel or crack leading to a waste of time and effort.
This means that your entire car surface should be closely checked for problems. Clean, scuff and sand to eliminate and imperfections, because all scratches and existing paint problems should be addressed before panel reﬁnishing.
Any surface not meant to be painted should be blocked off and taped to prevent damage. Use larger sheets to tape over your wheels and fender liners and adjust the paint tape around your windshield and window moulding.
Never use your hands when sanding your car, always use a sanding block to avoid any unnatural dips or curves left by your fingers.
Using high-build primer, apply even coats to a test panel and make sure to work in a well ventilated area, with the proper breathing aids. If you want a quick list of how to stay safe when working on your vehicle, check our safety guide here.
Continue until you have applied several coats to your entire vehicle. Now it’s time to block sand your car, using gentle pressure to reveal any low spots or dings in your sheetmetal. Rinse and repeat to eliminate any of the low spots or issues that may arise when block sanding your car.
Use a different can of primer to give you a two-tone effect, this method is known as the guide coat. This really shows you where the low spots are, as your base primer color is different than the one you are applying.
Block sand the car until you are satisfied with the results, and you can then move onto the finishing primer.
Clean your car by wiping it free of any particulates and oils with a gentle cleaning solvent. When you are certain the car is cleaned and ready, apply your finishing primer layer to your car.
Sand It.. Again
Using 800 grit sandpaper or above, gently wet sand your final layer of primer to give you a nice smooth finish. For large surface areas like your hood or the top of your car, try to be uniform and even in your sanding.
Wipe down the car and clean it again, making sure it’s free of any oils or contaminants.
Now it’s time to spray your car with primer sealer to lock in the surface you have worked so hard for. This sealer should be sprayed uniformly to give the new paint the surface it needs to adhere to.
Primer sealer can help catalyze your base primer and seal the compounds for a perfect paintable surface. You do not need to sand this sealer, simply wipe and clean once done.
Your car is now ready for paint, look up your local paint shop and see what the best price for car paint is in your area. Use a clean tack rag before it heads into the booth, and prepare to be amazed when it emerges. You now know how to prep car for paint, and you just saved yourself some serious cash with our DIY paint prep guide.
Is it really worth it for me to prep my car?
If you don’t mind paying the body shop to perform the same amount of labor, then no. But remember that paint prep determines how your paint sits on your car, and your time and work doesn’t literally cost you anything.
Why do I want to sand down to metal when prepping my car?
Water vapor plays a huge role here, because it can penetrate the layers of your paint. If your car is freshly painted, this effect is even worsened. Humidity combined with the fresh layer of paint can speed this process up, until it reaches bare metal.
Once this water vapor seeps under your paint, pressure can build from the rise and fall of temperatures. This pressure can bubble up and cause blistering of your car paint. Even worse rust can form under your paint, which will cause your layer of paint to lose adhesion and strip away.