In the 1920’s auto manufacturers had a problem. The only practical laquer or enamel that was usable was black in what was called the Japanning process. While varnishes in other colors were available the long application times and drying times precluded using them in mass production. In fact even the use of black was creating a production bottleneck for Ford.
Customers, though wanted more color in cars. Attempts though to use colors from woodworking and other uses just didn’t last. One customer complained that the finish peeled off in 90 days. That was a real problem when a brush painted finish could take longer than that to apply when drying time and sanding between coats is considered.
The problem is that unlike furniture which is not exposed to sunlight and weather or a railroad car which was essentially only painted on the car sides, an automobile is left out in the weather for long periods of time. Also, unlike a piece of furniture or railroad car, an automobile is made from thin sheet metal that is flexible. More flexible than varnish. This wasn’t as large a problem for luxury cars with their custom wooden coachwork, but for the mass production car to be colorful a new kind of paint was going to be needed.
Fortunately the paint manufacturers were ready to supply one.
The DuPont company came up with a nitrocellulose based lacquers that was more durable than the lacquers used before, held tint and most importantly for the auto industry dried fairly quickly.
DuPont began producing nitrocellulose-based pyroxylin lacquers after acquiring the International Smokeless Powder & Solvents Company in 1905. The purchase of the Arlington Company 10 years later deepened the company’s involvement. Although they were quick-drying and widely used on brass fixtures, conventional lacquers were too brittle for more demanding uses. By the 1920s, however, the automotive industry had become a huge potential market. Although mass production had vastly increased output, finishing remained a bottleneck because conventional paints took up to two weeks to dry.
In 1920, chemists working with film at DuPont’s Redpath Laboratory in Parlin, N.J., produced a thick pyroxylin lacquer which was quick-drying but durable and could be colored. DuPont marketed it under the name Viscolac in 1921. Assisted by General Motors (GM) engineers, DuPont refined the product further and renamed it Duco. The success of Duco led to further experimentation with finishes and late in the 1920s, DuPont developed Dulux, an even more effective alkyd finish. Duco retained a niche market, however, and DuPont continued to produce it at Parlin until the late 1960s.
DuPont has been using Dulux enamel in automotive coatings since 1926. Dulux actually owes its existence to a flaw in its more famous cousin, Duco. This nitrocellulose lacquer first brought color to automobiles when General Motors (GM) used it in 1923. It was thick and quick-drying, which pleased carmakers, but frustrating for consumers who couldn’t apply it like the oil-based paints they were used to. So DuPont researchers tried mixing synthetic alkyd resins with oil and found that the resulting enamel’s drying time was slower than Duco but faster than that of traditional oil paint. Dulux alkyd resin, named in 1926, also had a pleasing high-gloss look. By the early 1930s it won over consumers under the label Dulux “Brush” Duco.
Dulux high-gloss enamels were also used widely in the 1930s on refrigerators and washing machines, outdoor signs, gasoline service stations and pumps, and railroad cars. Once tried as an undercoating for Duco auto paint, Dulux also found a niche as a low-cost alternative to Duco auto finishes. In 1954 some automobile manufacturers chose an improved Dulux alkyd enamel over Duco, and over DuPont’s new water-based Lucite acrylic lacquer. However, Lucite soon pulled ahead in household sales, and after DuPont developed a new acrylic polymer in 1957, Lucite also outshone Dulux in the appliance and industrial markets. DuPont sold its consumer paint business in 1983.
The other issue was actually getting the paint on the car. The answer to that was the spraygun. The spraygun was first used at the Columbian Exhibition in Chicago where the painter needed to paint a lot of walls very quickly. It’s amazing how little the basic spraygun has changed over the years. For the auto companies the spraygun allowed finishes that were even, could be applied in controlled conditions and dried quickly. The difference in cars was immediate. Suddenly, in the 1920’s the roads became rainbows.
Since the 1920’s car finishes have become permanent and durable as car makers worked to finishes that provided ever greater protection from the elements. Where cars used to rust out in three to five years, these days it’s likely that a car will last a decade or more and it will be the powertrain, not the body or the finish that gives out.
Of course that durable finish may be one of the reasons that you can now just about buy any color you want on a car so long as it’s grey, white or black.
PS. Here’s an excellent reference on how color changed as technologies and styles developed.