By Jeff Ford
There is more awareness and interest today in reducing carbon footprints to benefit the environment.
Automotive paint manufacturers have discovered that altering paint composition to reduce the use of solvents greatly limits volatile organic compounds (VOCs) emitted into the air. This technology led to the creation of waterborne basecoat and high-solids clear coat – two separate products that accomplish the same goal and are becoming standard in body shops nationwide.
Waterborne paints are the future of automotive paint because they contain no harmful chemicals and dramatically reduce VOCs. In addition, waterborne paint eliminates the need for drying between coats and partially mixed cans of paint can be reused.
The waterborne equivalent for clear coats is the high-solids clear. High-solids clears have been around for a couple of years and are becoming more prevalent as states continue to amend U.S. Environmental Protection Agency VOC regulations and adopt more stringent rules limiting VOC emissions.
For shops affected by new mandates, transitioning to high-solids clears may leave shops questioning whether their techniques and processes need adjustments to continue efficiently producing high-quality results. Transitioning to high-solids clears is relatively simple. However, body shops need to pay close attention to paint finishing techniques with low VOC clear coats to ensure final finishes are blemish- and swirl-free. Here are five paint finishing tips tailored for shops using high-solids clears.
Product selection
Body shops should stick with one line of products from one manufacturer. This takes advantage of the fact that products are specially designed to work with each other. Mixing and matching products from several manufacturers is not only time consuming , it can be frustrating and may leave you with less-than-ideal results. 3M, for example, has developed a comprehensive paint finishing system that takes you through the entire painting process from start to finish.
Finish sanding
After the vehicle is completely cooled, remove minor imperfections in the new paint job by sanding dust nibs and orange peel with a DA sander. Use a small amount of water on the disc and on the surface. To further refine sanding scratches and eliminate imperfections, sand again with a P3000-grade disc.
Additional sanding with P3000 is critical with high-solids clears. The high-solids composition makes the clear more difficult to cut than traditional higher solvent-based versions. Therefore it is essential to sand and refine scratches as much as possible to reduce the amount of compounding time needed. Shops commonly estimate that sanding with a P3000 grade disc reduces compounding time by as much as 50 percent. While P3000 sanding is a step many body shops skip, the time saved makes scratch refinement critical.
Compounding
Compounds remove the sand scratches from the sanding operation. Compound-ing is the most labor-intensive part of the finishing process. To make the job as painless as possible, it's essential that shops prepare properly and use the highest quality products.
Compound selection is critical because low-quality products that either cut too fast or too slow will yield unsatisfactory results. High-solids clears tend to slow down the compound. Select a trustworthy, high-quality compound.
Begin compounding by smoothing micro scratches and imperfections from sanding with liquid rubbing compound and a wool or foam pad. Work a two-foot by two-foot area and maintain a thin, wet slurry across the paint for one to two minutes before the compound begins to dry. To finish, clean the compounded surface and wipe with a detail cloth.
Machine polishing
After the compound has been applied, a machine polish is used to eliminate compounding swirl marks. Machine polishing is most effective when applied with a rotary polisher and foam pad. Work a two-foot by two-foot area and use medium pressure. To finish, clean the machine polish off with a detail cloth.
Fine swirl removal
Fine polishing the paint job is the final step for darker colored cars to ensure swirls are eliminated. The final glaze should be applied with a rotary polisher and a foam pad – softer than the pad used to apply the machine polish. Do not polish the dry coat, and use a detail cloth to remove remaining material. The result is a beautiful high-gloss shine.
The most important tips to remember about the paint finishing process are take your time and keep a close eye on the surface to ensure the proper results. It also is a good idea to use a lint-free, non-scratching detailing cloth between each finishing step to remove abrasive residues.
For additional information about creating swirl-free finishes with high-solids clears, visit 3M's Web site at www.3M.com/automotive.
Jeff Ford is the technical services manager for 3M's Automotive Aftermarket Division, a global, diversified technology company based in St. Paul, Minn.
