Equipping For Waterborne: An Alternative For Low VOCs

Governments in North America and Europe are taking an environmental approach in passing laws restricting the quantity of volatile organic compounds (VOCs) in paint materials. Because of more stringent air quality regulations, low VOC requirements are making it necessary for paint technicians to switch to compliant coatings.

One alternative is waterborne paint, in which water becomes the major ingredient. According to paint manufacturers who provide waterborne products, there are several advantages to using water-base coatings: they contain and emit less organic solvent into the atmosphere; they may lower insurance costs (since water is the major solvent, the product is less flammable); and they presumably provide certain refinishing benefits and offer lower toxicity.

VOCs, or solvents, that are emitted from paint products react in the lower atmosphere to form ozone gas. This reaction creates smog, visible as a brown haze seen over most of our major cities. The paint companies agree that a certain amount of pollution will be reduced by replacing VOC solvents with water.

According to one paint company, waterborne products were initially introduced to body shops and paint repairers in California during the early 1990s, in anticipation of lower-VOC regulations. Few repairers see any improvement in the way today's waterborne primer/sealer covers. Some paint manufacturers suggest that a waterborne primer/sealer offers less shrinkage than solvent-borne, and that it forms a solid barrier under topcoats as a safeguard against basecoat lifting.

Body shops that have switched, or plan to switch, to waterborne coatings generally fall into one of the following categories:

Innovators - those who want to be first with the next generation of technology and look for new opportunities to help grow their business.

Environmentalists - those who are concerned about the quality of our environment and about improving the working conditions for their employees. They want to market their body shops as being "green."

Mandated by legislators - those who are forced to switch because of state VOC regulations or local by-laws.

There are three categories of waterborne products being used in today's body shops: cleaners, primers and basecoats. Since waterborne coatings are being utilized by body shops in certain geographical areas, it is important to understand both the benefits they produce and the specific equipment requirements for their use, storage and disposal. Some paint companies maintain that the benefits are substantial:

* Reduced solvent fumes means cleaner air and a healthier work environment. The painter will not have to inhale the dangerous and strong-smelling solvents.

* Waterborne paints are nonflammable; therefore, they reduce the risk of fire.

* Basecoat color match, metallic control and the ability to blend meet or exceed that of solvent-borne basecoats.

Some waterborne basecoat systems will not settle in the container and therefore will not require agitation, eliminating the need for expensive mixing machines and electrical connections. In comparison, poorly agitated solvent-borne systems will result in color match problems from pigment settling.

Any waterborne paint spilled on a painter's hand can be simply washed off with soap and water. However, gloves are recommended when handling all paint products.

Waterborne products can be applied with either conventional or high volume, low pressure (HVLP) guns.

Equipment And Requirements

When applying waterborne coatings, the first consideration should be equipment. Waterborne coatings can be applied with all of the usual application equipment. However, should you want to use electrostatic technology, the shop will have to isolate the electrostatic system from the ground.

It is important to keep the equipment and parts to be painted very clean. Waterborne paint is not tolerant of oils and dirt. Molded parts can carry residual mold release agents, stamped parts (commonly steel) can retain oils, and plastic parts can attract dust from the air through static buildup. Craters or fisheyes are a common result of these types of contamination. The shop may not need to drastically change anything it is presently using, but since water is a highly corrosive material, plastic or stainless steel internal parts are recommended.

Extra caution should be maintained when using equipment not specifically designed for water. The system should be thoroughly cleaned and flushed to prevent corrosion. If solvent-based paint is being used as well, the system must be flushed with a solvent (e.g., glycol ether or butyl cellosolve) and then flushed thoroughly with water. After applying waterborne coating, the opposite is necessary: flush the equipment with water and follow up with a solvent purge.

There are several minor adjustments required in order for a body shop to convert to waterborne coatings. The following equipment and other requirements for body shops that switch to waterborne products are fairly modest and will not necessarily break the bank.

Storage Temperature: Because the principle solvent is water, these coatings will freeze if exposed to freezing temperatures for a period of time. It is important to maintain storage temperatures above the freezing point, although it will take several hours before the product will actually "hard freeze."

Air Movement: To accelerate the dry time of waterborne coatings, an air movement system should be installed in the ceiling of a spraybooth for large paint repairs. A smaller, hand-held unit can be used for small spot repairs. A good unit runs on the same compressed air as the spraygun. When the painter is finished spraying each coat of basecoat, the unit is turned on for several minutes to flash off between coats. A unit can be equipped with a series of specific nozzles that direct a high volume of air at the surface of the vehicle in order to help evaporate the water from the basecoat.

Heat: Conventional or infrared heat lamps can be used to increase the drying time of waterborne primers or basecoats. They can be used alone or, preferably, in conjunction with air movement systems. When used alone, heat systems are not as effective, because they create a layer of water-saturated air just above the surface of the refinished area. Unless this water-saturated layer is removed by air movement, the effectiveness of heat application is reduced and drying is slowed down.

Cleanup and Disposal: It is poor practice and against the law to pour waterborne waste down the drain. Sprayguns and equipment should be cleaned with waterborne cleaners, specified by the supplier, in a separate system. A separate waste collection system dedicated to waterborne wastes should be used because solvent and waterborne wastes do not mix well and should be separated. There is no problem disposing of waterborne wastes as long as it is executed through a fully licensed waste hauler.

Health and Safety Equipment: Waterborne products can offer a number of benefits to the paint refinish industry. However, paint manufacturers recommend that paint technicians who handle and spray waterborne products use the personal protective equipment specified on the suppliers' MSDSs and labels. If the body shop does not have MSDSs for the products being handled, they can be easily obtained through a jobber or paint supplier. It is important that the technician read all instructions and cautions before using waterborne products. It is to the benefit of the technician's health and safety.

Spraybooths: In order to ensure the highest quality of work with any waterborne system, a spraybooth should be used, preferably a down-draft style booth. Paint companies may often recommend a down-draft spraybooth to obtain the best paint repair results from the solvent-borne urethane systems. However, it is not necessary to apply waterborne primer/sealers in spraybooths, because the drying time is not as significant as with basecoat or clearcoat products. Waterborne primers can be sprayed in well-ventilated prep decks. As with solvent-borne products, waterborne requires specific conditions and lighting, as well as climate-controlled spraybooths.

At least one recycling manufacturing company is offering a method of collecting water-base overspray in order to help the environment. Accordingly, they have developed and marketed a long-lasting, non-soluble collector that can provide high-efficiency filtering of water-base coatings.

Paper and cardboard water-soluble overspray collectors can break down as they filter water-base paint particles from vented air, and quickly become matted and block essential air flow. It is important to research all equipment necessary for water-base coatings.

The durability of waterborne products may equal that of solvent-borne, but paint companies suggest that waterborne basecoats may use less material for coverage. However, this varies from shop to shop.

Notwithstanding, waterborne products are recommended for, and used in, geographical areas where the climate and humidity make them more suitable because of their water base. Waterborne products are not recommended in extremely humid areas, because the high humidity will impede the drying time.

Profit And Productivity

And then there is that other issue--cost. Costs per sprayable pint/quart/gallon for low-VOC waterborne products may be significantly lower than for solvent-bornes. This is the kind of difference that can put a severe dent in a repair shop's profitability.

According to one paint manufacturer, the owners and managers of successful collision repair businesses understand that numbers do not lie when it comes to productivity and profitability. When one product allows the repairer to put more vehicles through the shop per day, at a greater profit margin, and with equal or better quality, that is the kind of business decision that makes an immediate impact on the bottom line.

However, even though waterbornes may be economically easier, storage and hazardous waste removal is just the opposite. Water-base products have an unstable shelf life. They become contaminated more easily and more quickly, and it is more costly to dispose of the hazardous waste material.

Water-base products will build pressure within the can when stored. Unlike solvent-borne waste which is easier to burn off and recycle, water-base products can not burn off or be distilled without serious modifications to the recycler. In addition, some waste haulers are charging a higher rate to remove water-base waste materials.

Are We Ready For Waterborne?

Waterborne products require some new equipment, some modifications to existing solvent-borne equipment, and a lot of patience. With waterborne coatings, good clean-air movement is necessary for proper drying in order to achieve a quality finish.

A good and reliable filtered down-draft spraybooth is ideal. However, some paint manufacturers suggest using a cross-draft spraybooth. Conventional booths do not offer the proper air movement necessary for appropriate water evaporation. Without suitable movement and infrared heat, the water-base will just sit on the paint surface, creating a crude, uneven finish and prolonged drying time.

As with any new product, there are benefits and drawbacks. Water-based products give us a cleaner environment, but is it worth the conversion investment? Only shops experimenting with waterbornes can answer that question. Some have raised the following concerns:

First, shipping water-based products is a serious obstacle. Because the material is considered unstable, it must be shipped in heat-controlled trucks to avoid freezing. This expense is inevitably passed on to the repairer. And, eventually, to the consumer.

Second, storage can also be problematic because of the potential for freezing and contamination to the product. Because water-base products will not replace all solvent-borne materials, there must be two prescribed areas for product storage.

Third, converting to waterborne coatings may not be all that economical for every repairer, because the product must be applied in a controlled environment. Perhaps only 50 percent of collision repair/paint shops would consider converting because of the necessary climatic conditions.

Fourth, there are no water-base clearcoats: vehicles still require a solvent-borne finish coat. This not only requires two areas of storage, but also two procedures for hazardous waste management.

Finally, it is imperative that water-base spray equipment be cleaned and purged between each color change.

Even waterborne manufacturers admit that waterborne primers can become seedy and coarse, and the top coatings do not offer the texture of solvent-borne finishes.

Opposing Views On Waterborne

Some manufacturers maintain that waterbornes provide a viable route to achieving compliance. However, this is only one such alternative.

Several body shops in California were surveyed about their use of waterborne products as a means of complying with low-VOC regulations. Most said they are not using any water-base products, and have no plans to switch from solvent-borne. Low-VOC surveys conducted throughout the state may be quoting false waterborne percentages, since there are several solvent-borne alternatives that offer low-VOC primer/sealers, as well as high-solid paints. Waterborne products are only one example.

The shops that have experimented with water-base primer/sealers and basecoats share negative views about the products. Water-base coatings dry slowly, usually leaving a blushing or seedy finish, and some shops are experiencing complications in blending. Problems with blending, basecoat coverage, drying and experimenting with spraybooth acceleration all affect production. Waterborne products, as well as low-VOC solvent-bornes, require a longer flash time between coats. This is a definite concern in regard to daily paint and assembly production. Sometimes it is important to lose some quantity in order to achieve quality.

As countries strive to improve air quality, the use of alternatives such as waterborne coatings will likely increase. It is no coincidence that some carmakers have already switched from solvent-bornes to waterbornes. The benefits can be substantial,but some modifications to equipment and work practices will be necessary to achieve maximum productivity from these systems. Waterborne products may not be the answer for everyone, but they are one alternative to low VOCs.