Automotive News - August 11, 2008 - (Page 36k) INSIGHT continued from previous page AUGUST 11, 2008 • 36K der system in these plants is primarily in response to new VOC regulations,” she says. Lis says GM is one of the first companies to use color-specific primer surfacers. The primers, used at Lordstown, match the color of the base coat. Color-matching the primer reduces the amount of base coat required to cover the vehicle. Last December, GM installed its own version of a three-wet paint operation at its assembly plant in Toluca, Mexico. Toluca’s three-wet system also uses a high-solids primer that eliminates the need for a primer spray booth and oven. The plant builds medium-duty commercial trucks and the Chevrolet Silverado and GMC Sierra pickup trucks. The high-solids primer used at Toluca is solvent-based. Lis says GM is developing a water-based version of a three-wet paint. While one strategy to reduce VOC emissions involves conversion to powder- or water-based coatings, Lis says, GM’s larger goal is to reduce total emissions. “A large part of this is not targeted specifically at VOC emissions but more at reducing energy load and overall emissions of carbon dioxide,” she says. the automotive industry for more than 15 years. Effy Carpenter, PPG global product manager, says the demand for powder coatings is increasing. ‘Greenest of green’ “Powder coating is VOC-free,” she says. “It’s the greenest of green.” General Motors uses a powder primer surfacer at five assembly plants. Three of them — in Lansing, Mich.; Lordstown, Ohio; and Oshawa, Ontario — converted to powdered primer in the past two years, says Karen Lis, a GM advanced technology engineer. “The implementation of the pow- Measuring footprints Ford’s Weingartz says the total environmental impact of a given paint or coating can only be accurately evaluated with a life cycle analysis. Such an analysis shows that the carbon footprint of water-based coatings is larger than that of the solvent-based three-wet system. The carbon footprint measures the impact of human activities on the environment in terms of the amount of greenhouse gases produced. “The carbon footprint of a paint operation really comes from the processing side rather than the material,” Weingartz says. “Water-based paints need to be dehydrated and force-flashed, which requires moving a lot of air through a football-field-sized drying booth. There’s a huge energy consumption.” Reducing waste is another way to make a paint operation more environmentally friendly. Gage Products Co. recently developed a VOC-free purge solvent that is used at Ford’s truck plant in Louisville, Ky. The solvent is used to clean the plant’s paint lines. Ford had used a VOC-based solvent to purge the paint lines, but the resulting residue had to be disposed as a hazardous waste. In switching to a VOC-free purge solvent, Ford eliminated more than 260,000 gallons of hazardous waste, saving over $300,000 in disposal costs annually. Mark Weisman, Gage’s sales manager, says the plant’s acceptance of the new purge solvent ultimately rested on its effectiveness. “Green is great,” Weisman says, “but the challenge was to prove this worked as good as or better than the old VOC-based solvent.”c From left, Tim Weingartz, paint engineer; Mary Ellen Rosenberger, paint manager at Ford’s Avon Lake, Ohio, assembly plant; and Dennis Havlin, another paint engineer, led the team that installed the environmentally responsible paint process at the plant. Pick your paint poison Both water-based and solventbased paints offer environmental advantages and disadvantages. Here’s a summary of their strengths and weaknesses. Solvent-based Pro: Coating layers require less heat and energy to dry, leading to a possible overall reduction in greenhouse gas emissions Con: Contain volatile organic compounds, or VOCs, that readily evaporate and contribute to air pollution Water-based Pro: Contain no or smaller amounts of VOCs Con: Generally require controlled humidity, temperature and movement of large volumes of air to dry properly, which may result in an overall increase in greenhouse gas emissions As we open Nucor Steel Memphis, Inc., champagne, ribbon cutting, and fireworks do not concern us. The only celebration we want is the roar from the electric arc furnace recycling its first batch of Special Bar Quality steel. Because with every ton of steel, we roll out a new era in Special Bar Quality steel manufacturing: the widest range of SBQ products, engineered precisely to specification, with a commitment to on-time delivery. Now that should be something for you to celebrate, but pardon us if we skip the brouhaha. We’ve got orders to fill. www.nucor.com/sbq It’s Our Nature.® http://www.nucor.com/sbq
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