5 Tips for Using Paint Primer on Cars

A man puts primer on a car.

There are plenty of tips that can help you mix paint primer. Any car that has had the paint stripped down to the metal will require you to use a primer before painting the car your desired color. The main purpose of the primer is to smooth down the surface of the car, provide something for the topcoat to stick to, and keep the steel panels of your car together. All primer will need to be mixed before it can be applied. These tips will help you prime your car properly.

Prepare the Car

Before you apply primer you will need to properly prepare the car. This may include sanding and washing off any dirt or dust. The surface needs to be clean when you put on the primer. The car also needs to be completely dry. Make sure you prepare the car in a well-ventilated area so you do not have to keep moving it. There are three different types of primers you can use. Many times primer can also be used to reduce corrosion as well as a surface filler.

TIP: Ed Kimble, our painting expert, points out that it's important "to make the right choice on your primer otherwise you may experience paint bubbling."

A man primes a car.

Understand Different Primers

There are three different types of car primers: wash etches, etch primer, and high-build primers. Etch primers are used to reduce corrosion and are mainly phosphoric acid primers. They will protect your car even if the paint has chipped. Wash etches are a thin primer that you can brush directly onto the car and does not require a sprayer. This primer is perfect if the car has been stripped bare. A high-build primer is used at the end of repairs as it can be used for filling or flattening out marks. It is very thick and can be tricky to apply.

Tint Your Primer

You may also want to tint your primer if you think it will show through your base coat. Normally primer tints are available in gray, white, and beige. There are also spectral primers available if you need a specific color.

TIP: Ed suggests: "You can also tint your own primer by mixing in a small amount of the desired old paint to create a lighter color for your car."


Most primers will have their own recommended ratio of paint thinner to primer. Many people will use half thinner and then half primer. Primer normally has a ration of 2 to 1 so you need 2 parts primer to 1 part thinner.

TIP: Ed also adds: "It is very important that you follow the instructions otherwise you will not get the correct application. When mixing, it is best to use a calibrated mixing cup to be as accurate as possible. You can purchase special paint mixing cups at hardware and automotive stores."

A man primes a car.

Use a Spray Gun

Most people will use an automotive spray gun to apply the primer. For this, you will need to have a safety mask on when painting. Do not pour the primer directly into the spray gun cup but first place a strainer in the cup and then pour in the primer. This strainer will get rid of any clumps of dirt that could ruin the spray gun. You may not need to use a spray gun. Using one, though, ensures an even coat which is important when applying primer.