At the turn of the 20th century, the automobile industry was in its infancy. Auto paint at that time was inherited from horse carriage production, but new paints became necessary as the automobile grew in popularity and performance. Auto paint has changed throughout history from varnishes applied by hand to high-tech paint and overcoats used today. As the composition of paints changed, so did the application methods and equipment.
Varnishes
According to J.G. Dickson's article "50 Years of Epon Paints" in PCI Magazine, auto paint initially consisted of the varnishes used to paint horse carriages. That method took as many as 16 coats, each applied by hand with brushes. Those varnishes were slow to dry, and it take up to a month to paint one vehicle. One advantage to varnishing was that an automobile owner could perform touchups and patching himself. Varnish finishes, called India enamel, were dark earth tones with few colors on the palette. Those finishes were fairly weak and prone to fading in the sun.
Nitrocellulose
Early in the 1920s, paints based on nitrocellulose appeared. Based on purified cellulose from wood, the paint was then soaked in a combination of nitric acid and sulfuric acid. According to AutoInc Magazine's online edition from May 16, 2001, nitrocellulose paints dried much more quickly than previous paints and varnishes, and many more colors were available.
Alkyd resins
Next in the development of auto paint, in the early 1930s, were alkyd resins used in the manufacture of alkyd enamels, according to the Learning Center at TCPGlobal.com. Those enamels were made from animal- and vegetable-fat glycerin that was used in solvents and explosives. Alkyd enamels could be called the first stage of contemporary automotive paint and painting techniques. They provided a high gloss finish and fairly large selection of colors. They were more durable than the earlier generation of paint, and also dried faster.
Lacquers
World War II interrupted car production for a time, but afterward auto manufacturers began using acrylic lacquers. Lacquers were a huge advancement because of immensely shorter drying times, and that resulted in faster assembly-line production. The number of available colors also increased dramatically. Lacquers, however, had to be buffed after drying to bring out the shine.
Up to the 1950s, Detroit-based auto paint companies were the major players in the industry. According to George Barris in vol. 4 of his "Barris Kustom Techniques of the 50's" series (Thaxton Press, 1997), at that time several California individuals and companies entered the arena, adding various dyes, inks and toners to clear lacquers to achieve a show quality. They often called the bright colors "candy" or "kandy," as in "candy apple red."
Acrylic resins
Improvements in using acrylic resins in enamels came along several years later. Those paints did not require buffing for a high gloss and also provided better resistance to harmful ultraviolet rays from sunlight. They were more durable as well. Shortly after introducing those enamels, developers incorporated catalysts that increased durability even more.
Primers and overcoats
Primer substances improved as well, especially the use of electrophoretic deposition (a form of "electroplating") to apply the primer paint directly to the metal so that rusting was almost eliminated. In that process, an electric current runs through metal submerged in a chemical bath, producing a coating on the metal's surface.
In the 1980s, finishing techniques began to include applying a basecoat under the color as well as a clearcoat finish on top, which provided a durable finish for high gloss and resistance to chipping.
Green technology
The latest technology involved in auto paint is abatement of harmful chemicals getting into the environment. According to an article in PCI Magazine on April 26, 2002, titled, "Transparent Iron Oxide Pigments for Automotive Applications," because of environmental restrictions, there is continual pressure for the development of water-based paints and other products that do not leach harmful solvents into the environment.
0 comments:
Post a Comment