Waterborne Automotive Coatings
Solvent-based paints, paint strippers, equpiment cleaning solvents, used in the collision repair industry contain toxic materials, in some cases at very high levels. As of 2018, as many as 64 percent of collision repair shops had converted to waterborne paint (Autobody News, 2018).
Waterborne paints are a practical, environmentally friendly alternative to solvent-based paint. Transitioning is relatively painless, but there are some subtle differences in spray nozzles, air pressure, dry time, thinning, spray technique, and stirring; all easily incorporated with minor training and assistance from suppliers.
Waterborne requires dedicated spray equipment, including optimized tip size, and resistance to water corrosion.
“It wasn’t a difficult decision. The common thought is that it’s difficult to make the switch, or people think it’s too expensive to switch – it’s not.” Lisa Thompson, President, Heitzman Body & Paint, Ecobiz Certified
Why switch? There are many reasons, but here are some of the most compelling with respect to human and environmental health:
Personal Risk: Most solvent-based automotive paints contain isocyanates. Isocyanates include compounds classified as potential human carcinogens and known to cause cancer in animals. Solvents may cause occupational asthma and other lung problems, as well as irritation of the eyes, nose, throat, and skin. Isocyanates, and some solvents can penetrate the skin, sometimes even through latex gloves. While today’s personal protective equipment has never been better, it is common to see career auto painters with chronic exposure issues such as asthma or central nervous system damage (e.g., shaky hands). Less obvious impacts can be liver or kidney damage and impaired coordination.
Business Risk: Most collision repair shops are located near other businesses or even near residential areas. Odor complaints are common and occasionally neighborhood groups petition to have the business relocate. Also, states have been increasing permit costs for shops that continue to use solvent-based paints.
Environmental Risk: Solvent-based paints release VOCs and regulated hazardous air pollutants (HAPs) during application and cleanup. Automotive painting releases about 70,000 tons of VOCs annually, which are contributors to smog and poor air quality. In 1999, when nearly all auto painting was solvent-based, collision repair shops released 45,500 tons of known and suspected cancer causing chemicals into the air.
While waterborne house paint has been safe and effective for nearly six decades, waterborne automotive paint has a more dubious history. Waterborne auto paints had the unfortunate experience of being brought to market before they were really ready. As a result, the decade of the 1980’s saw numerous coating failures, most prominently poor adhesion that caused peeling, that was mostly attributable to improper drying of primer coats. This resulted in the perception, that has proven hard to dispel, among many painters, that waterborne paints were the the cause of the problem. The fact is, that while waterborne paints are less tolerant of surface imperfections, adhesion to a properly prepared surface is every bit as good as solvent-based paints.
Waterborne paints cost more up front, but any excess does not have to be immediately thrown away, may not have to be treated as hazardous waste, and more often than not, waterborne requires fewer coats than solvent-based paints.
There have been complaints of changes in the paint drying or curing time and equipment. Low-cost dryers that create turbulent airflow can result in drying times that compete with solvent-based paint drying times.
Some OEM’s are using waterborne clear coats at the factory and they are becoming available as an aftermarket product. Clear coats will continue to improve with time, while waterborne primers and basecoats are effective.
Finish Quality: Waterborne primers and basecoats achieve excellent penetration. Color match ability is excellent. There is consensus that waterborne paints provide a superior color match and have better metallic lay-down on autobody surfaces.
Avoid Future Regulations and Costs: States are cracking down on VOC and HAP emissions. In particular, VOC emissions in the auto body industry are regulated under the “National Volatile Organic Compound Emission Standards for Automotive Refinish Coating”. The U.S. Environmental Protection Agency (EPA) has developed the Collision Repair Campaign, a voluntary effort aimed at reducing exposure to toxic air emissions from collision repair shops. The campaign helps shops work toward compliance with EPA’s Auto Body Rule.
In high-smog states like California, regulations requiring low-VOCs technologies have been in place for years, with many other states considering similar laws. Some HAPs are regulated under EPA’s 6H NESHAP rule, which requires extra documentation and painter training. Making the transition sooner rather then later may save many businesses time, money, and regulatory burdens.
Waterborne paints are significantly less flammable, and some shops have been able to reduce insurance premiums.
Reduce Employee Exposure: While waterborne is not completely free of harmful chemicals, it is less toxic then solvent-based. In fact, VOC exposure when painting with waterborne paints can be up to 56 times lower. (Liao 2015). Painters, other shop employees and customers all enjoy the absence of strong solvent smell. Using waterborne and proper personal protective equipment (PPE) can eliminate both acute and chronic overexposure issues for painters such as asthma and kidney, liver and central nervous system damage.
Improve the Bottom Line: Waterborne paint tends to have higher pigmentation then solvent paints, which improves the base coats ability to hide what is underneath. A job that requires three to four coats of solvent-based paint will only need two coats of waterborne.. Many waterborne paints do not require mixing systems, only a slight shake before straining. Perhaps most important for a business, shops report that with the right drying systems, their throughput increases.
Preconceived Notions About Waterborne Automotive Paint
Spray Efficiency Training (PPRC): Learn about and practice technique refinements that can reduce paint overspray for waterborne (or solvent-based) applications, save money, and achieve NESHAP 6H compliant training for operators. To sign up for spray efficiency training or learn more, message Ken Grimm.
Safely Switching from Solvent-Based to Waterborne Paint (EcoTech Systems, LLC, 2021)
Waterborne Coating Technologies Steadily Advance Despite Challenges (American Coatings, 2020)