Technology in Action: The Evolution of Auto Paint
What’s the first thing you noticed about your car? It probably wasn’t the engine’s horsepower or the power steering. Was it the sparkling, shiny paint job? Whether your car is Anaconda Green, San Marino Red or Heaven Blue, its paint is one of its defining aesthetic characteristics.
You’ve likely painted the walls of a house or apartment before, but you’ve probably never taken a paint brush or a roller to your car’s paint job. But, that’s exactly how the first auto paint was applied more than 100 years ago. Automakers started painting cars around 1900, and it could take up to 40 days to apply a paint job. These early cars were brushed with varnish, which came from the era of horse-drawn carriages. After the varnish dried, the car was sanded, refinished and polished.
By the time the Roaring ’20s rolled around, the car painting process began to speed up. Automakers like Henry Ford began using nitrocellulose lacquer, which had a quicker drying time, on assembly lines. Then, in 1924, paint spray guns made their way onto the assembly lines, as well. The spray gun made it possible for workers to paint cars more quickly, and it also applied the finish in a more consistent manner. As a result, cars didn’t need as much sanding between coats, and a car could be painted from start to finish in a third of the time that it used to take.
The painting process was further refined within a decade, as car companies started using finishes known as stoving enamels, which boasted a glossier finish and quicker drying time.
General Motors started using a new acrylic coating in 1955, which further expedited the painting process. Vehicles were sprayed with the enamel and then baked in an oven, which resulted in a smooth and consistent finish. While this method was quicker and more cost-effective, it didn’t produce the same glossy finish as stoving enamels. Ford refined the process in 1960, when it began using acrylic stoving enamels, which were also painted on with a spray gun and oven-baked, resulting in a resilient, glossy finish.
By the 1970s, European and Japanese automakers had developed two-coat acrylic painting systems, as well as metal flake paint jobs that were popular in the U.S. However, it wasn’t long before automakers started to want harder, more durable paints that also dried more quickly. Many automakers started applying polyurethane and urethane finishes by the late 1980s, and they also began applying a clear coat to improve the color and luster of the vehicles rolling off the assembly line.
The painting process is even more advanced today. Carmakers like Hyundai use a process known as electrocoating, which involves submerging the chassis in primer or paint and using electricity to draw the finish to the sheet metal. Hyundai coats its vehicles 11 times in a primer bath before painting and assembly, and with the exception of final inspection and polishing, its methods are completed entirely by machines.
So, you may not have thought about it before, but a lot of technological advancement has gone into creating that eye-catching finish on your ride, no matter what color you choose.