Imperative to hardwood finishing is wood preparation. Allowing stain and finish to evenly settle in the surface pores evenly, the woodworker must remove all indentations, oil and other defects. Only then can dyes, stains or fillers be applied.
Keeping in mind the difference between close and open grains are imperative to understanding the nature of wood staining. Open grain hardwoods, such as elm, oak, and ash are ring-porous species with distinct figure and grain patterns. Close Grain hardwoods, such as cherry, maple, birch, and yellow poplar with small, dense and subsequently less distinct patterns.
With certain closed-grain woods, you will also experience finishing blotches thanks to textured grain. These will never disappear regardless of how well you prepare the wood. Aside from these imperfections, sponging the surface with water is also useful for exposing glue, marks or grease.
Producing deep, rich hardwood finishes is possible by performing a two-step staining process. Synthetic dye concentrates can be suspended in water or alcohol, and then sprayed onto the wood prior to using a pigmented wiping stain. This two-step process may be used on all species of hardwoods, and will provide depth and uniformity of color that is unachievable in a one-step pigmented stain process.
Subsequent to all of these coloring and staining steps, a toner may be sprayed over any of the previously discussed stain systems to develop the desired hardwood color. A toner may be mixed with one part pigmented wiping stain and four parts acetone. Toners will even out variations in the color of the wood, such as between plywoods and hardwoods, as well as add more depth and strength to the overall color.