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Waterborne Paints: What You and Your Customers Need to Know

By Mark Clark

New regulations will require paint companies to use water as a solvent in base coat paints. How will this affect you and your customers?

The buzz in auto body these days is about new California regulations that will require paint companies to use water as a solvent in base coat paints. Because southern California’s air quality is so poor, the South Coast Air Quality Management District (SCAQMD) has amended its famous “Rule 1151,” effective July 1, 2008. Rule 1151 was created in 1987 when these same government regulators called for body shops within its jurisdiction to apply paint with spray equipment that had at least 65 percent transfer efficiency. High-volume, low pressure (HVLP) spray guns not only complied with that new rule but became the industry standard nationwide.

Will these requirements reach you, wherever you are in the U.S.? HVLP spray guns did. While mandated for only a few areas, the merit in less overspray, more paint on the car worked for everyone. When I started writing this story I thought it was unlikely this waterborne paint technology would spread across the country. Now I’m not so sure. California and other Air Quality Management Districts either have, or will soon have, similar rules to the South Coast rule. Canada has plans to require similar limits in 2010. The UK adopted limits that require water resins on January 1. Spain, Germany, Belgium and the Netherlands have used similar low-VOC coatings for several years successfully.

Most of the air pollutants still come from internal combustion engines, but 12 percent comes from paints and solvents. Because Southern California’s smog problem is so severe, SCAQMD often finds itself at the forefront of the nation’s emission reduction efforts. On many days, the ozone that forms pollution makes the air so hazy that any view, toward any horizon, has visibly brown air between a person and his objective. Like Jimmy Buffet sings, “I just spent four lonely days in a brown L.A. haze.”

The SCAQMD board effectively made HVLP an industry standard nationwide. Will the same thing happen with the new amendments for even lower volatile organic compounds (VOCs)? Time will tell. For now, those body shops within the SCAQMD must be using a paint system that complies with the more stringent VOC rules by next summer. And this will affect the jobbers and WDs that service them.

Previous regulations allowed painters within the SCAQMD to comply by stacking VOC emissions among a system of coatings. For example, the combination of base color and clear coat couldn’t exceed 3.5 pounds of VOC per gallon of paint under the old rules. New rules will ultimately call for each paint component (primer, surfacer, sealer, color, clear, bed liner, etc.) to meet set VOC limits on its own. On July 1, 2008, the first two product changes become effective. Clear coat must not exceed 2.1 lbs of VOC per gallon and color coats must be below 3.5 lbs of VOC. A gallon of auto paint weighs roughly 10 lbs, a VOC limit of 3.5 lbs means that 6.5 pounds of the gallon must be solids and only 3.5 lbs. can be solvents. A limit of 2.1 lbs means that roughly 7.9 lbs must be solids and only 2.1 lbs can be solvent. To get the base color coat under the required 3.5 lbs VOC by itself, paint manufacturers must use some combination of exempt solvents, co-solvents and water to reach the 3.5 lbs VOC goal.

Solvents like acetone aren’t counted in the VOC total because the Federal EPA has said they are exempt because they don’t contribute to the formation of ground-level ozone buildup. The SCAQMD’s primary concern is that volatile, organic material be removed from paint coatings so that it can’t evaporate into the atmosphere and react with sunlight to form that noxious brown air. All auto paint manufacturers selling in Southern California will have less than 3.5 pounds of volatile organic compounds in their versions. Some of them will have much less than 3.5 lbs per gallon. Not everyone has the same approach to compliance. Some manufacturers even have patented technologies in the hopes of making their compliant offerings more desirable than the other guys.’
How each manufacturer chemically constructs its color coatings affects its product’s properties. Every paint company I spoke with will employ some combination of co-solvents (works with water, acts similarly to current auto body solvent technology), exempt solvents (not counted in the VOC total) and/or treated, de-ionized water (no VOC by itself) to blend the compliant offerings. Your current paint brand is surely working on its compliant version. As always, following the exact directions for your particular brand is the surest road to success with any auto paint finish.

Water-compatible resin has some issues in auto body that it doesn’t have in house paints. First, understand that this isn’t tap water in either case. The water the chemists want to use in paint is the purest possible. No minerals. It’s filtered, purged, distilled, de-ionized and electrocuted. Water is a one-speed solvent; the ability to switch to fast or slow evaporating solvents to accommodate changes in the local weather isn’t possible if your reducer is water. Unless the humidity exceeds 100 percent, water will evaporate. Heat helps, along with lower humidity, but the most important element appears to be air movement. Southern California shops will have to increase their air movement while keeping the heat up. What moving air and heat combination will be required for your brand to work best? Ask your paint reps; they’ll know just what their particular chemistries require.

Some pigments respond differently in water than they do in solvent-based resins. Some systems suspend their pigments in a ‘micro gel’ that resists settling, some use tints very much like their current solvent system but then add water in the final reduction. That method requires mechanical agitation just like mixing tints. Some other technologies require only a light hand agitation. A simple rocking back and forth is correct for those brands. Too vigorously whipping the mixing tint like a rattle can will cause you to whip air into the resin. Air and water together make foam — a foamy resin doesn’t readily intermix with other components. You can wait for the foam (air) to settle out, but it’s better not to ignore the directions. In every case, some agitation is necessary for mixing tints — understand what your brand will require.

Water is susceptible to freezing in transport. The duration of the sub-freezing temperatures matters. One brand said its product is unaffected by a freeze of less than four hours. In some brands this would not affect the product and in others it would ruin it. Several manufacturers intend to monitor the environments in which their products pass through on the way to the shop. By attaching a hi/lo peak thermometer to all winter shipments, they could record the lowest (and highest) temperatures a pallet of product had been exposed to. Other tell-tale signs include ink capsules that break below freezing and even credit-card sized devices that check and record the temperature every 10 minutes, downloading the data via a USB port. High temperatures can affect water-based paints too. Over 120 degrees, at least in some brands, can cause problems with the resin. And yes, it will cost more to ship freezable resins in heated trucks — but not that much more.

Everyone I spoke with was pricing their compliant product lines competitively. The new stuff will likely be ‘comparable’ in price to the old stuff. Having heard about the extraordinary expenditures paint companies have and will have to outlay in an effort to help shops comply, I’m thinking there’s going to be some R&D expenses they’d like to recover. Developing new resin bases, reformatting many color matching tools and conducting shop tests, all add to their cost of goods, not to mention training costs.

Everyone I interviewed has training classes to get their shop customers up to speed before the July 1 deadline. It’s a huge cost to the paint manufacturer to develop and present the training to the techs who must be away from work to attend. However, everyone agrees that training the painters to use new technology is the single biggest key to success. Training programs for jobbers are an important part of the paint manufacturer’s implementation plans too. Well informed jobber salespeople are always a key to successful market changes. Educated jobbers will make the transition to new SCAQMD requirements much smoother for everyone.

Cleaning waterborne paints from spray guns is also an issue. The painter will need to clean the gun as soon as possible. In some cases, with some brands, if you let the paint dry and set inside the spray gun it can be very difficult to remove. The dry film is impervious to solvent (it’s water-based), sticks to metal gun parts better than solvent base and is no longer very water soluble. Getting it out of a gun could be tough. Every manufacturer will sell or recommend a particular cleaning solution for their resins.

Shops will need to keep the waste stream separate from the solvent waste too, all the other coatings are still solvent base. Any shop that is permitted by the EPA to generate waste will not need another permit for waterborne waste. The hauler may charge more to remove water-based waste, in part because it won’t have the same BTU content when burned as fuel, which is what happens to much of the current solvent-based waste.

In general, the water resins require a dedicated spray gun that doesn’t shoot solvent-based anything. That gun must have stainless steel, brass or plastic parts to prevent rust. Some manufacturers are suggesting a move to smaller fluid tips, others suggest a change in air caps. For certain, water resins atomize, flow and spray somewhat differently from solvent resins. Specially designed air caps and correct fluid tips will help get the best results.

Compressed air will have to be maintained much better in many shops. Moisture in compressed air lines will affect dry times, finish quality and even durability of water resins. A desiccant dryer or refrigerated air dryer and clean and functioning moisture traps are necessities to make the new paints work well.

Bombarding the waterborne color coat with lots of moving air will make it dry faster. Some shops are investigating a spray booth retrofit that puts big fans inside the booth or mounts air jets all around the car. Other shops intend to succeed with just hand-held air vortex guns. These venturis, either pistol-grip or mounted on a multi-holder stand, increase the volume of air by pulling in ambient air when the compressed air rushes through the funnel. European auto painters have used waterborne paints for almost 10 years with minimum modification to spray booths. The shops I spoke with found they could employ the handheld air blasters easily and the water resins looked very nice.

Other paint-shop changes might include the quality of the prep work. If it is true that the opacity (ability to hide) is higher in these new paints, then you will reach color and appearance match with less material. If so, painters will have to learn to mix less. Better surface prep is essential. It will be necessary to sand with finer grits if the paint isn’t as thick.

Populated and potentially polluted areas like the northeast United States, the industrial states that surround the Great Lakes and other populated areas, are likely to take a turn to become ‘greener’ and the SCAQMD regs will likely become the model legislation for those areas. At some point, if enough of the US population is regulated by low VOC requirements, the paint companies and jobbers will opt to carry and promote one paint line. And it’s likely to contain some water.

What’s the good news? These new finishes are better for the environment and potentially provide a healthier workplace. Color match appears to be more than acceptable. Your customers will need a new spray gun with rust-proof parts and specific fluid tips and air caps, a method to blast a bunch of air at the car to dry the paint film, a new gun washer with special cleaning solvent, some training on mixing ratios and agitation requirements, and most importantly a willingness to change.

I predict great success. The auto body industry has proven time and again that no matter what the change, driven from the DOT, the EPA, OSHA or any other scary government acronym, they can and will figure out how to make it work. Low VOC color coatings will be no exception. It’ll take a little while. Any product switch in an auto body paint shop is likely to cause an initial decrease in production. You knew all the shortcuts with the old stuff and it will take a while to uncover the shortcuts with the new stuff. I’ll wager that by July 2009 the shops in the SCAQMD will be turning out great looking work in a hurry, with a product that helps keep the brown air at bay.

  Previous Comments
avatar   ANA LAURA   star   8/27/2009   4:53 PM

In my personal opinion, it is very important to be well informed about waterborne. Not just the body shops and body man, but also the people who work at a paint store. It is important because we can give the most recent information about waterborne.

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