Application Techniques For Clear Wood Finishes

The movement toward “green” products that reduce harm to the environment is far from a fickle fashion — it is the basis for a new way of life in the paints and coatings industry. And one of the strongest examples is the development of waterborne clear wood finishes that are low in volatile organic compounds.

When it comes to clear wood finishes, the big green revolution is in interior applications. Inside homes and businesses the low odor and fast-drying qualities of waterborne finishes are highly valued.

However, these same qualities call for some adjustments in application techniques by professionals who are accustomed to applying oil-based varnishes.

Acrylics dry faster and form a thinner film than old-style varnishes. This means that more coats may need to be applied to reach the desired thickness, while at the same time, they can be applied more quickly. Joel Hamberg, president of Joel Hamberg Painting Inc., Portland, Ore., says this factor is a benefit in scheduling work. “Think of how efficient you can be with scheduling when you have predictable drying times and less down time. Your customers will be so pleased to put their rooms back into use within hours instead of days.”

Over the course of one restaurant renovation, Hamberg’s crew refinished wood surfaces on the front door, sidelights, vestibule, window panels, accordion doors, grand staircases, trim, wall paneling, fireplace and art framework without interfering with the restaurant’s regular hours. “Drying times were so predictable that we could tell the restaurant staff exactly which areas we would need readied for each night’s work,” Hamberg says.

Faster dry times mean some painters will have to change their brushing techniques. Work needs to keep up a pace that will maintain a wet edge so the finish will be smooth. Ron Franklin, owner of Ron Franklin Painting & Decorating in Sacramento, Calif., warns against letting fresh material go over material that is starting to set up. “It won’t be smooth,” he says. “Get the material on fast and don’t overwork it trying to get it even. Lay it off with the brush one time and get away from it because it’s already drying and getting stiffer. Get it on nice and even and fast.”

Franklin gives an example of a colleague who applied a waterborne finish to a large section of wood paneling using the same technique he had always used with oil-based finishes. He finished the top half first and then moved down to do the bottom. The result was a lap mark that ran all the way across the middle of the paneling. The problem with using that previously successful technique was the waterborne coating’s faster dry time, or shorter “open” time.

When using a waterborne on a project like this, Franklin recommends taking the brush from the top down the complete length of the panel or door, then repeating the process all the way across so there is always a single wet edge that can be brushed into before the coating dries.

Softer tools
Waterborne coatings require using different tools to avoid showing brush marks and other imperfections. “For low-VOC finishes you’ll want a tool that’s very soft. Anything with coarse ends will show brush strokes,” explains Reid Parks, PSB product manager for Bestt Liebco, a division of Sherwin-Williams. White china bristle brushes, widely used with oil-based finishes, are soft, but they absorb water and become spongy. Instead, Parks recommends synthetics like nylon. For example, Syntox brushes from Purdy are made with a blend of nylon and Chinex filaments. Syntox filaments are tipped and flagged, making the brush ends very soft. While brushes like these were developed to simulate natural bristle or ox hair, they have the added advantage of longer life because the filaments don’t get brittle or break off. “I used to buy bristle brushes — ox-hair or china,” says Franklin. “Now I buy more nylon.”

Brushing is usually the preferred technique, but Parks says rollers can be used for larger areas. “With a roller, you want to use something with a low nap height to get a smooth finish. Try to find 1/4 inch or less. Also, choose something that won’t leave lint behind. Mohair or a mohair blend is what we recommend for a high-glass, smooth surface. Also, high-density white-foam minirollers will leave a nice smooth finish.”

The water’s fine
With these simple adjustments in application techniques, painters are ready to take advantage of all the improvements waterborne finishes deliver. In an article posted to the Painting and Decorating Contractors of America Web site, Hamberg writes about the advantages of waterbornes for painting contractors and their employees. “Say goodbye to respirator fit testing, suffocating respirators or off-gassing. You won’t miss getting lightheaded and headaches from fumes, will you? What a relief to your family to not be distressed by clinging odors on your breath and clothing! Have you noticed how many in the industry are becoming chemically sensitive from being exposed to current formulations? Your employees’ health and your personal health are worth the cost of switching.”

There are efficiency advantages too. Setup and cleanup are faster, simpler and less costly with waterborne finishes. No containment tents or ventilation fans are needed. Brushes can be cleaned with soap and water. And disposal is simple because it involves no solvents or hazardous wastes. Finally, the lack of solvent odors means the space can be occupied in just a few hours.

Waterbornes also deliver an attractive finish. Bob Jones, technical marketing representative in Seattle, Wash., for Kelly-Moore Paints, says, “There is a long-standing trend toward more satin finishes — they’ve been popular for a long time now. People also like waterbornes for their clarity. And they are less likely than oil-based or alkyd varnishes to yellow. The trend to waterborne will continue to grow.”

Hamberg sees this as a great opportunity for the industry. “This is a good time to be a painter. It’s an exciting time. You don’t have to sacrifice your health — there are great choices for your workforces and customers. We’re getting some energy going. A lot of the oil-based finishes are going to be dinosaurs with the next wave of low-VOC products, so make changes now.”