How to Prep a Car before Painting: Cutting, Sanding, Priming and Picking the Right Paint
Ask any automotive professional about painting a car, and they’ll tell you the same thing: it’s all in the preparation. Whether you’re repairing a chip or re-spraying the whole car, prepping the paintwork is just as important as applying the paint, and will massively impact upon the end results.
To help you prep like a pro, here are some tips on sanding, priming and picking the right paint for your car’s paint job.
Find Your Paint
Cutting is a term used to describe the use of an abrasive compound to remove thin layers of paint. Cutting can be carried out as a prep step before you apply paint or afterwards to blend the new paint into the old. There are different types of compound, each with a different cutting power. Be sure to choose the right one for the job – ask your local automotive store for help in choosing the right one for you.
When applying a cutting compound, always take care to mask off surrounding areas, especially if you’re applying it with a machine. The compound has a tendency to get everywhere, so work smart; wear old clothes or overalls, safety glasses, gloves and cover anything you don’t want to have to clean up afterwards.
Apply the compound in a random circular motion by hand using a clean cloth. For larger areas this can be too much effort to attack by hand so get an orbital polisher with the appropriate pads. Don’t press too hard at first and pause every now and then to inspect the area you’ve just treated.
When you first start out there’s a good deal of trial and error to this as paint type and hardness can dictate how long and how many applications will do the job. Always take care to move the compound around and don’t spend too long in any one area as this can heat up the paint and burn it, creating more damage than before you started. Sprinkle or spray water on the surface from time to time as this will cool the paint down and help to move the compound over the surface.
Sanding is one of the most important parts of paint preparation, and investing time to do it right will deliver professional results. Depending on the job, sanding can be done with either sand paper or an electric orbital sander, and you’ll need to use different grades of paper depending on the task.
If you plan to strip paint from the car’s bodywork, use 1200-grit paper or sanding pads to quickly remove the clear-coat and paint. There’s a good chance that you’ll need to remove the primer and expose the bare metal to avoid the headache of trying to match the paint you want to apply to the existing paint on the car. Paints, especially those on older cars, may be incompatible with modern water based paints and gel coats. Better to be safe than sorry – do it right and do it once.
Alternatively, if you don’t need to completely repaint the surface and you’re doing a quick repair or touch up, smooth the surface using 2000 – 2,500-grit wet and dry paper. Press lightly to remove minor light scratches in colour coats and clear coats quickly.
Priming is an essential step in painting metal surfaces, and you’ll need to prime before applying any top coat or colour to the car. Primers seal the surface and create a protective barrier. They also create the ideal surface for the colour coat paint to adhere to. High build primers contain high solids which help to smooth any imperfections on the bare metal.
Always choose a high quality automotive primer that’s developed for use on metal surfaces, and make sure the area you plan to paint is cleaned thoroughly before you start. Typically you should apply two or more coats of primer to ensure the bare metal is completely covered. If you’re painting plastic, you’ll need a specific plastic primer.
Pause and inspect the area. This is the ideal time to take stock of the situation and work out if any further surface prep, such as sanding, needs to be done. You can clearly see any surface imperfection once the primer has dried. Don’t skimp or rush this key stage. Remove any bumps or rough patches by re-sanding the area. Clean and re-apply the primer. It’s normal to have to repeat this stage a couple of times to get it right. This is the best tip for a flawless professional finish.
Choosing the Right Paint
Whether you’re giving your car a fresh new paint colour, or matching the existing paint you’ll need the correct shade. With thousands of different colours available this might sound tricky, but Holts Paint Match Pro makes it easy.
Using our clever paint match tool, you can quickly find the right paint for your car based on its manufacturer, colour and registration year. With over 8,000 vehicle colour matches across the range, you’re sure to find the paint that’s the perfect match for your car’s paintwork.