Door maker converts to water-based finishes.

New coating system unlocks the benefits of waterborne technology for Northwest Door and Supply.

Switching from a solvent-based to a waterborne wood finishing system requires a good deal of research and planning. While there are obstacles to incorporating a waterborne finishing system into almost any wood products operation, doing so can result in a number of significant health benefits, as illustrated by the experience of Northwest Door and Supply Inc. of Tualatin, Ore.

Northwest Door's first brush with waterborne coatings was in 1993 when the company implemented a system comprised of Sher-Wood Wiping Stain Concentrates from Sherwin-Williams combined with a water-reducible lacquer. After an initial adjustment period, the company found that the new system enabled it to meet current and future federal and state air quality regulations while providing customers with an attractive and durable finish, improving the working environment for employees and eliminating hazardous waste disposal costs.

Sound strategy

Northwest Door is no stranger to risk. The company was started in 1981 with just three employees, used equipment, one truck and a rented 8,000-square-foot facility. Its four founders - Tom Holmes, Chuck Sauvain, Merle Lundel and Bob Greig - all had left stable jobs to form the start-up venture, organized to supply Portland-area contractors with custom-made, pre-hung interior and exterior doors, window surrounds, mouldings and handrails for homes, apartment complexes and light commercial facilities. The company also distributes windows and garage doors.

Double-digit sales growth for each of its years in business has enabled Northwest Door to grow to a point where it now employs 56 and occupies 50,000 square feet of space. Nine sales representatives cover more than 300 miles of territory in Oregon and southwest Washington, visiting every job site to measure openings to ensure an accurate fit.

Northwest Door purchases door models or door blanks from three suppliers, which allows the company to offer more than 200 types of exterior wood and metal doors and interior doors in species ranging from mahogany to oak. The company also maintains a half-million dollar inventory, which it turns twice a month. This allows Northwest Door to supply contractors quickly.

Production & finishing

After receiving an order and measuring the door opening for the project, a door is pulled from stock, cut to dimension and finished to specification. A Norfield Magnum pre-hung door machine is used to bevel doors, bore holes for locks and mortise hinge and door jambs. Northwest Door also will add headers and door jambs to the frames and insert glass if ordered.

Before the finishing process begins, all door components are hand sanded. All doors, mouldings, window surrounds and handrails for a given order are finished collectively to assure a consistent finish.

Northwest Door has 15 finishers covering three shifts. Door components are attached to hooks and hung on a 60-degree automated conveyor system controlled by the finishers. Stain is applied in a 16-foot by 5 1/2-foot spray booth before the components enter an adjacent drying room in which the temperature is maintained between 85F and 90F.

After the stain has dried, the lacquer is applied in the same booth with airless spray equipment before the components are sent back to the drying room. After the lacquer has dried, each component is sanded by hand with 220-grit sandpaper before the second and final coat of lacquer is applied. Once the final coat dries, the door systems are assembled and door hardware is installed. A lineal coater is used to apply the finish to window surrounds and mouldings. The coater also is capable of capturing overspray for reuse.

Lessons learned

One concern of Greig's was that the waterborne system would be harder to work with than traditional nitrocellulose lacquers, a fear that proved to be largely unfounded. "While we did have a learning curve and had to make some adjustments to our processes, we found that the more we used the water-based system, the better we got at it and the better it performed for us," he said.

As part of the system implementation, the company purchased Graco airless spray equipment and added a 20-foot by 15-foot drying room. Northwest Door also stopped heating its spray guns, a practice which had improved the application of the previous finishing system but adversely affected the flow of the waterborne system.

One problem that occurred initially was black spotting when oak was handled soon after the application of lacquer. "We found that the spots occurred when the tenons in the oak combine with the water-based system and fingerprints," Greig said. The problem was solved by having employees don rubber gloves when handling oak doors.

According to Greig, Northwest Door decided to switch from solvent-based coatings to a waterborne finishing system to be prepared for current and future changes in VOC regulations. "We also knew that water-based systems offered lower odor for a better working environment for our employees and would eliminate the costs associated with hazardous waste disposal," Greig said. "But we decided that if we couldn't find a waterborne system that would produce a quality finish, we wouldn't use one. We would have opted to find other ways to meet VOC regulations rather than let a poor-quality finish hurt our business."

Greig said he was pleased to discover that advances in waterborne technology, primarily in resin chemistry, have resulted in the creation of new waterborne coatings that provide clarity, indistinguishable to the eye from solvent-based wood finishes. The six primary concentrated pigment stains and 10 additional colors he selected accent and highlight the woodgrain while providing clarity and workability. The lacquer is an acrylic latex system that also provides film clarity and resistance to yellowing. It dries quickly so finished products can be handled and recoated in one hour at 50 percent relative humidity and 77F.

"While switching to a waterborne system wasn't simple, it was well worth it," Greig said. "We now have a high-quality, efficient wood finishing operation for the future."