Here’s How To Mix Automotive Paint

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? Marvelous! But you’re overwhelmed by the variety of paints available and how to mix them? Rest easy, you’ve come to the right place.

Automotive paint formulas vary by decade, with lacquers, enamels, and urethanes making up the major paint types available. Older lacquer formulas are more susceptible to fading than modern mixtures but are easy to apply and period-correct for classic cars like that Trans Am. Modern urethane formulas are long-lasting but require specific mixing and application steps that may be challenging for DIYers. 

The bottom line is your car’s paint affects its value. If you’re willing to adhere to the proper mixing methods, you can do it yourself and save money. The Drive’s crack How-To team is here to help, so let’s get your car looking factory-fresh. Stirrers at the ready!

How To Mix Auto Paint Basics

Estimated Time Needed: 30 minutes

Skill Level: Intermediate to Garage Hero

Vehicle System: Exterior

Auto Paint Mixing Safety

Working on your car can be messy. It can also be dangerous. Paint, solvents, and other hydrocarbons can irritate the skin. Here’s what you’ll need to ensure you keep your jeans, shirt, and skin spotless, and your bones intact.

• Nitrile gloves (to repel chemicals used).
• Long-sleeve shirt to protect your arms.
• Eye protection.
• Mask or ventilator (optional).

Organizing your tools and gear so everything is easily reachable will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the paint stirrer or blowtorch. (You won’t need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)

You’ll also need a flat, well-ventilated, enclosed workspace such as your garage’s workbench. The key is to prevent particulates from getting into the paint, which will thwart your Concours d’Elegance dreams, while ensuring ample ventilation, which will keep you upright (paint fumes are noxious). 

Everything You’ll Need To Mix Automotive Paint

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

Tool List 

• Pre-marked paint mixing buckets 
• Paint stirrers

Parts List

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

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 consult your owner’s manual or your local dealership to determine the right paint for your car and follow the instructions carefully. 

Here’s a rundown of the types of paint and how to mix each properly.

Acrylic Lacquer

Acrylic lacquer was an early industry standard that was phased out by the 1980s.  In states regulating the use of harmful volatile organic compounds, or VOCs (hello California), acrylic lacquer paints are illegal. Acrylic lacquer paints are easy to use and produce a glossy finish, but are more susceptible to damage from UV rays than a modern urethane-based paint-and-clearcoat treatment is. Some classic-car restorers still use acrylic lacquers to maintain a factory-correct look on vintage cars that aren’t used as daily drivers.

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 several minutes, making sure the consistency is uniform. 
6. You did it!

Acrylic Enamel 

Acrylic enamel creates a hard exterior shell-like acrylic lacquer, but lasts longer and provides better UV protection.

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.

Mixing Acrylic Enamel One 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 as 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 together. 
7. At the indicated time, add the hardener, filling the container to the right 8:1:1 level.
8. Stir the mixture together.
9. You’re ready!

Mixing 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. Wipe it out if necessary.
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 together. 
6. Done!

Clear Coat

1. In a second pre-marked container, inspect for any dust and debris. Wipe it out if necessary.
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. You’re done!

Urethane

Urethane paint is extremely resistant to rock chips and fading, and looks fantastic when applied correctly, but those properties come at a cost, which is generally higher than other automotive paints. 

Urethane is also 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 total wanted paint thickness, which may require you to use paint thinner, and isn’t usually recommended for weekend warriors. 

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. Wipe it out if necessary.
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.
7. All done!

Clear Coat

1. In a second pre-marked container, inspect for any dust and debris. Wipe it out if necessary.
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. You’re done!

Acrylic Urethane

Acrylic Urethane is now the industry standard as it provides long-lasting UV protection, excellent resistance to chips and dings, and is cheaper. 

But like Urethane, ambient temperatures will affect what types of urethane activator is 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. Wipe it out if necessary.
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.
7. All done!

Clear Coat

1. In a second pre-marked container, inspect for any dust and debris. Wipe it out if necessary.
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. You made it, congrats!

Pro Tips For How to Mix Automotive Paint

Here are pro tips for mixing paint:

• Mix a small amount of paint ahead of the full amount. You can then apply this small batch to a test site to ensure your ratios are good and have the effect you wanted, all while not potentially ruining the rest of the paint.
• 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. 

How Much Does It Cost To Paint Your Car

Paint pricing can vary depending on how much paint is required, 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, depending on if you have the time and tools to finish the job. Large-scale resprays where a certified professional is required can cost many thousands of dollars, again depending on a number of factors.

Credit: Jonathon Klein, The Drive