Step One in Finishing 11/8/2011 5:05:00 PM 
So what is the first step in the finishing process? Is it staining? Or surface preparation? Well, even if you’re making paint grade cabinets, isn’t wood selection really the first step?
Wood selection must take into account several factors:
- What is our target market and what is our customer’s preference? Some customers are looking for a painted wood finish. Others want what’s generally referred to as a “clear” wood finish. The word clear in this context distinguishes this type of finish from a painted finish in that the wood grain is visible. The degree of clarity varies greatly by the type of coloration that’s applied to it. A “natural” finish is a clear wood finish with no colorants added.
- What are the skills of our workers? Once we select woods for high-end applications, our workers must arrange them on our products in an aesthetically pleasing manner. This can mean anything from blueprint matching veneers in a whole room to selecting boards of solid wood for color and figure compatibility on a piece of furniture.
- What are the cost considerations? High-end finishes require more careful selection and the cost is substantially higher no matter how it’s done. If selection is done by your supplier, the cost will be significantly higher per unit. If you or your employee goes to the supplier and selects it, the cost in time spent may be even greater.
Even when using wood for what is to be a painted surface, wood selection plays a significant role. If you want the texture of the wood to telegraph through, you’ll be looking for a wood where the grain is distinctive. Pine, for example, will show raised areas where the annual rings define the difference in density between the softer spring growth and harder summer growth. If you don’t want any of these features to show through, you’ll pick a wood that minimizes the texture of the grain, such as poplar or even a composite such as MDF where applicable. Another consideration is the overall absorbency of the wood. More absorbent woods will require more finishing effort to achieve a full, even luster.
Wood selection becomes more critical when we’re looking to create a clear wood finish. This type of finish varies greatly and the wood we select can determine a lot about what we are able to achieve as a final result. At one end of the spectrum is a finish colored by semi-opaque, pigmented colorants and finished off with a matte finish. At its extreme, it resembles a painted finish. On the other end of the spectrum is a finish colored by a dye that penetrates the grain and finished off with a high gloss, hand rubbed finish. This is the ultimate finish for showing off highly prized, figured woods. Most finishes lie somewhere in between. A natural finish is near the high end of the spectrum.
With clear finishes, the wood provides not only the base for the texture of the finish as with painted finishes but the first step in coloration as well. The fact that this coloration is not consistent is one of the characteristics of wood that make it unique and beautiful. On the other hand, this variation in color may be seen as a handicap in some situations and that’s why we find such variations in finishing techniques.
The more opaque end of the spectrum requires a less stringent wood selection. Only the defects that show a lot of contrast need to be eliminated. These defects may include knots, mineral deposits, splits, and high contrast figure that’s inconsistent. Especially obvious are mismatched edges of adjacent boards or leaves of veneer. The more opaque the finish, the less fussy the selection needs to be. We see a lot of these finishes on furniture over the last century and a half. It lends itself to low cost, high production operations.
At the other end of the spectrum is the finish designed to enhance and magnify the grain characteristics of the wood. A lot of care must be taken in wood selection since defects and mismatched grain will be obvious, especially when dyes are used to accentuate the grain. Surface preparation is also critical since machining or sanding defects will be magnified along with the grain. The features of the grain not only produce variations in color but appear three dimensional. The color and contrast actually change as the angle of view and/or the light sources change. This phenomenon has been documented and terms used to describe it include: chatoyance, birefringence, and metamerism. It’s important to be aware of these things when selecting wood since they can cause a color mismatch in adjacent pieces of wood that otherwise appear to be a good match. But for the right customer, it’s all worth it.
Wood selection needs to be appropriate for the job. Knowing your customer’s preference is critical in making the right choices. You also need to know how the finishing process can be used to enhance and/or mask the attributes of the wood.
