How To Mix Auto Paint

Like cooking, the right ingredients at the right times will make all the difference.

byRobert Bacon| UPDATED Jan 20, 2022 5:40 PM
How To Mix Auto Paint
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So, your Pontiac Trans-Am is no longer as bitchin’ as it once was, and you want to return it to glory with a fresh coat of paint? Fantastic news, but mixing auto paint isn’t as straightforward as one might think. Luckily, you’ve got The Drive’s crack how-to team to back you up. Mixing automotive paint can be broken down into four main categories, and we’ll detail the process for each type.

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How to Mix Auto Paint Basics

Estimated Time Needed: 30 minutes

Skill Level: Intermediate to advanced (depending on paint type and conditions)

Vehicle System: Exterior

Auto Paints, Depositphotos

What Is Auto Paint?

Automotive paint is the type of paint used on vehicles for both protection and decoration. It’s made up of three main ingredients: pigment, thinner, and binder.

Mixing Auto Paint Safety

Working on your car can be dangerous and messy, so here’s exactly what you’ll need to ensure you don’t die, get maimed, or lose a finger and that you keep your jeans, shirt, and skin spotless—hopefully.

Everything You’ll Need To Mix Auto Paint

We’re not psychic, nor are we snooping through your toolbox or garage, so here’s exactly what you’ll need to get the job done.

Tool List

Parts List

  • Paint
  • Thinner (also called reducer)
  • Hardener
  • Activator (urethane paints)

Organizing your tools and gear so everything is easily reachable will save precious time in any job. You’ll also need a well-ventilated flat workspace, such as a garage floor, driveway, or street parking. Check your local laws to make sure you’re not violating any codes when using the street because we aren’t getting your ride out of the clink.

Apply the paint., Depositphotos

Here’s How To Mix Auto Paint

Automotive paint can be broken down into four basic categories: acrylic lacquer, acrylic enamel, urethane, and acrylic urethane. Each type requires a slightly different recipe and mixing method, so here’s a breakdown of all four methods.

Mixing Acrylic Lacquer (Ratio 1:1 Paint/Thinner)

  1. Inspect the pre-marked mixing container for dust and debris. Wipe it out, if necessary.
  2. Find the 1:1 ratio markers on the container; pour in the paint.
  3. Using a stirrer, mix the paint to blend the pigments fully.
  4. Using the 1:1 ratio markers as a guide, pour in the thinner.
  5. Mix the paint and thinner together for minutes, until the consistency is uniform.

Mixing Acrylic Enamel 

Acrylic enamels are separated into two categories: single-stage, which dries to a glossy finish, and two-stage, which includes a base layer of pigmented paint and a separate clear coat. The clear coat adds a glossy finish and extra protection.

Acrylic Enamel Single Stage (Ratio 8:1:1 Paint/Thinner/Hardener)

  1. Inspect the pre-marked mixing container for any dust and debris. Wipe it out, if necessary.
  2. Read the paint’s instructions on when to add each ingredient since some require the hardener to be added at a specific time.
  3. After you find the 8:1:1 ratio markers, pour in the paint.
  4. Using a stirrer, mix the paint to blend the pigments fully.
  5. Using the 8:1:1 ratio markers, pour in the thinner.
  6. Mix the paint and thinner. 
  7. At the indicated time, add the hardener, filling the container to the right 8:1:1 level.
  8. Stir the mixture together until its consistency is uniform.

Acrylic Enamel Two Stage (Base Coat Ratio 1:1 Paint/Thinner, Clear Coat Ratio 4:1 Paint/Hardener)

Base Coat

  1. Inspect the pre-marked mixing container for any dust and debris. 
  2. After you find the 1:1 ratio markers, pour in the paint.
  3. Using a stirrer, mix the paint to blend the pigments fully.
  4. Using the 1:1 ratio markers, pour in the thinner.
  5. Mix the paint and thinner. 

Clear Coat 

  1. In a second pre-marked container, inspect for any dust and debris. 
  2. After you find the 4:1 ratio markers, pour in the clear coat.
  3. Stir the clear coat to make sure consistency is correct.
  4. Using the 4:1 ratio markers, add the hardener at the indicated time.
  5. Stir it until the hardener is blended evenly.

Urethane

Urethane is tricky to mix and apply, as ambient temperatures will determine which type of urethane activator is needed (fast, medium, or slow). Other factors that affect urethane application are humidity, airflow, and desired paint thickness, which may require you to use paint thinner, making this a job for someone with advanced knowledge of mixing paint.

Mixing Urethane Multi-Stage (Base Coat Ratio 4:1 Paint/Activator, Clear Coat Ratio 4:1 Paint/Hardener)

Base Coat
  1. Inspect the pre-marked mixing container for any dust and debris. 
  2. Find the 4:1 ratio marker and pour in the paint.
  3. Using a stirrer, mix the paint to blend the pigments fully. 
  4. Using the 4:1 ratio marker, pour in the correct activator (fast: below 70 degrees; medium: 70 to 80 degrees; and slow: above 80 degrees).
  5. Stir the paint and activator to combine.
  6. Repeat the process, allowing for drying times, if further base coats are required.
Clear Coat
  1. In a second pre-marked container, inspect for any dust and debris. 
  2. After you find the 4:1 ratio markers, pour in the clear coat.
  3. Stir the clear coat to make sure consistency is correct.
  4. Using the 4:1 ratio markers, add the hardener at the indicated time.
  5. Stir until consistent throughout.

Acrylic Urethane

Like urethane, ambient temperatures will affect what type of urethane activator needs to be used (fast, medium, or slow), and humidity, airflow, and total wanted paint thickness can require additional steps and considerations. This isn’t recommended for weekend warriors.

Mixing Acrylic Urethane (Base Coat Ratio 4:1 Paint/Activator, Clear Coat Ratio 4:1 Paint/Hardener)

Base Coat
  1. Inspect the pre-marked mixing container for any dust and debris. 
  2. Find the 4:1 ratio marker and pour in the paint.
  3. Using a stirrer, mix the paint to blend the pigments fully.
  4. Using the 4:1 ratio marker, pour in the correct activator (fast: below 70 degrees; medium: 80 to 70 degrees; and slow: above 80 degrees).
  5. Stir the paint and activator to combine.
  6. Repeat the process if further base coats are required, allowing for drying times.
Clear Coat
  1. In a second pre-marked container, inspect for any dust and debris. 
  2. After you find the 4:1 ratio markers, pour in the clear coat.
  3. Stir the clear coat to make sure consistency is correct.
  4. Using the 4:1 ratio markers, add the hardener at the indicated time.
  5. Stir until both liquids have mixed thoroughly.
Mixing Colors, Depositphotos

Pro Tips for Mixing Auto Paint 

Here are pro tips for mixing paint:

  • Mix a small amount of paint ahead of the full amount. You can then apply this batch to a test site to ensure your ratios are good and have the effect you desire. This could save you time and money.
  • Car manufacturers often have car-coded paints available through dealerships or online. They tend to be pricier than aftermarket paints, but using these paints ensures an even hue. 

Video

In the video below, Kevin Tetz from Eastwood shows you exactly how to mix automotive paint using a mixing cup.

FAQs About Mixing Auto Paint

You’ve got questions. The Drive has answers.

Q. How Much Does it Cost to Paint Your Car?

A: The cost of painting your car can vary, depending on how much paint is required, the type of paint used, and whether or not you’re doing it yourself or using a professional. Smaller, DIY paint jobs can cost as little as a few hundred dollars, but large-scale resprays where a certified professional is required can cost thousands of dollars.

Q. How Long Does Clear Coat Paint Last After Activating?

A: Once you’ve mixed the ingredients, your clear coat should have a pot life of 6-8 hours. 

Q. Does Paint Hardener Spoil?

A: Yes. Once you’ve opened the container of paint hardener, or activator, it will start to go bad. How much air in the container and the ambient temperature of the room will determine how quickly the hardener spoils. 

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