The paint that protects and beautifies cars have changed a great deal in the last 100 years. Not only have they evolved from naturally-based products to fully synthetic ones, the method of applying them has changed from hand brushing to being applied by robots. Thanks to information we gleaned from the body shop guys at Fletcher in Franklin, IN, a Dodge, Chrysler, Jeep, Ram dealer, we have put together a great article here that follows the history of automotive paints and finishes.
Originally done by hand
In the early part of the 20th century, automobiles were painted by hand. The paints consisted of natural products (often linseed oil with natural pigments) and the painting process took many days. It probably goes without explanation that this part of the process created a serious bottleneck for the production plant. The car manufacturers soon leaned on the paint companies to come up with a quicker process.
DuPont rose to the occasion in the early 1920s with its new lacquer paint product. These paints were based on nitrocellulose and were applied via spray guns. The car manufacturers were thrilled as this speeded up vehicle assembly time a great deal. While lacquers were a major step forward, multiple coats were still needed and drying had to occur in between coats. Lacquers also have poor resistance to common automobile fluids. Repeated exposures to gasoline spills, for example around the filler cap, can damage lacquer finishes.
Then in the 1930s, enamel paints began to appear. Enamels were sprayed on vehicles via spray guns and then were baked in ovens. This greatly speeded up the manufacturing process and produced a rock hard finish which was resistant to solvents. However, enamel paints weren’t perfect. While they looked beautiful on the show room floor, they oxidized when exposed to direct sunlight for long periods and this caused the colors to fade. This tendency was improved considerably with the introduction of “acrylic enamels” in the early 1960’s. Acrylic enamels were far more resistant to oxidation and available a wider range of bright, pleasing colors – especially metallics.
In the late 1970s, a new type of finish started to appear on European cars. It was called “basecoat/clearcoat.” Basically this type of paint consisted of a colored enamel basecoat topped by an ultra-hard clear enamel. This two coat process allowed a great deal more flexibility in the composition of the base coat (more colors and metallics) because the top clear coat functioned as a protectant. By the late 1980’s this paint system had become widespread in the US. In fact, only a small percentage of cars manufactured today, do not use basecoat/clearcoat paint systems.
While the basecoat/clearcoat paint system is far superior to conventional one-coat enamel paints in many respects, it has a few disadvantages. The clearcoat has a greater tendency to show erode when rubbed by foreign materials. Overtime, the clearcoat can deteriorate too and it can’t be “buffed out” like the older enamels could.
Note: It is important for car owners to realize that waxing and buffing is not a process that is normally performed on basecoat/clearcoated cars. You can still wax your car but you need a special non-abrasive formulation so the clearcoat isn’t eroded. Check with your local car dealer for further information.