WoodDigest.com |

If you attended the IWF show in Atlanta this August, you probably heard a lot of buzz about water-based finishing. The latest trends in finishing are quickly moving in the direction of “eco-friendly” water-based coating technology.

If you want to be on the cutting edge of the green finishing revolution, you will need to consider how to move from solvent-based coatings into water-based finishing processes. Whether you are a small or large manufacturer, there are new water-based finishes that meet the most demanding finishing requirements. These coating system technologies range from UV-cured materials, pre- and post-catalyzed coatings, to mono-component finishes. As a general rule, most of these coating systems and application processes are significantly different from solvent-based systems. To be successful in water-based finishing, the finisher will need to rethink the process from start to finish. Here are some key points to consider before switching from solvent-based to water-based finishing systems.

SUBSTRATE SURFACE PREPARATION

The average final whitewood sanding abrasive material grit for solvent-based finishes ranges between 150 to 220 grit. When using water-based finishes, the final whitewood sanding abrasive grit ranges between 220 to 280 grit. Moving to a higher abrasive grit for water-based will allow for a higher polish of the wood to reduce fiber raise and minimize stain blotching of the wood. Remember, water is a very effective solvent for opening up the pores of the wood, which allows for good adhesion of the finish, whereas solvent-based stains and finishes will not have sufficient penetration at this level of sanding. One advantage of water-based finishes is that variations in stain color will not be as problematic as in solvent stains when the sanding and polishing preparation of the wood is inconsistent. Softer species of wood will stain best when up to 280-grit sanding abrasive is used. Harder tight-grained species of wood may need to be sanded with an abrasive as low as 220 grit.

WOOD STAINING PROCESSES

Traditionally, finishers have used solvent-based wiping stains as the most commonly used material for color development when using solvent-based finishing systems. Many water-based wiping stains do not produce the same effect in color development as do solvent-based stains. Some water-based wiping stains can be harder to apply and wipe to achieve a uniform stain color. Although, newer water-based wiping stains are much easier to use, it may be difficult to achieve an exact match when trying to switch from a solvent-based to water-based stain formulation.

This is not to say water-based wiping stains are not aesthetically pleasing. Some water-based stains have great clarity and a clean look that is different from solvent stains. It is our recommendation to create a new color pallet, if possible, to avoid attempting to exactly match a solvent-based stain system.

Rather than using water wiping stain, most stained finishes can be successfully achieved by a spray-only no-wipe stain. These new water-based spray and no wipe stains are very easy to apply and can closely resemble the look of a solvent-based wiping stain. These stains use super finely ground dyes and pigments that provide a clean look but will also enhance the definition of the grain like a solvent-based wiping stain. Another advantage is these spray-to-color stains generally tend to give a more uniform look with less blotching of the grain and darkening of the end grain.

WATER-BASED GLAZES

New technology and formulations have greatly increased the workability and desirable aesthetic effects that can be achieved with a water-based glaze. Unlike the old formulations, these new glaze technologies are usually fairly workable and have good open time to allow for wiping and brushing the glaze. However, with most of these glazes, they will wipe and hang in the crevices and profiles differently than long oil glazes. The finisher should not have the same expectations for water-based and solvent-based long oil glaze materials. Some very pleasing effects can be achieved using a water-based glaze; however, the effect will not exactly replicate the look of a long oil glaze.