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When automobiles were first built in the 1890s, the builders adopted coatings used at that time for painting horse drawn carriages. These coatings were made from natural oil-based materials like linseed or soybean oils. These paints would take weeks to dry. After World War 1 when the popularity and acceptance of the automobile was really taking off, paint companies started to use alkyds, which are chemically modified oils. Dry times for these coatings were reduced from weeks to days for the entire painting operation. This was still a major problem for manufacturing because the paint application and dry time took longer than the time it took to build the vehicle. Automobile manufacturers began baking the vehicle body shells at higher and higher temperatures to shorten dry times. This was the beginning of OEM paint processes differing from refinish operations. |
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By the 1930s, automobiles started becoming status symbols. Because of that, the appearance and the durability of the paint finish became increasingly important. Some automobile manufacturers used nitrocellulose lacquer to achieve a deep rich color and glossy finish. This type of lacquer required multiple coats to build the correct film thickness because the paint was diluted with a lot of solvent. After the paint film dried, the finish had to be buffed and rubbed to obtain a high luster. The disadvantage with lacquer is that it tends to dull over time and often requires extra buffing to restore the gloss and richness of the color. In older movies, think of how often the chauffeur was shown polishing the finish of the limousines. The same type of paint was used in the refinish industry to repair these nitrocellulose lacquer factory finishes. After WW II, some vehicle manufacturers began to use acrylic lacquer for the paint finish. Acrylic lacquer was better than “Nitro,” but still used high volumes of solvent to thin the paint to sprayable consistencies. Because the paint was thin, multiple coats were required to achieve the required film thickness. Even though acrylic lacquer was an improvement over nitrocellulose lacquer, the drying time was still over an hour after the application of multiple coats. Neither Nitro nor acrylic lacquer “cures.” Either finish can be dissolved months after application with a strong solvent. These lacquers became popular for hot rod enthusiasts. Vehicles with this type of finish were refinished using the same paint that is used in production. |
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