Choosing to pickle knotty pine is a great way to highlight the unique grain and imperfections in the wood. Pickling is a staining technique that can be done with either a pre-mixed pickle stain or a self-prepared mixture. Either way, the process of pickling knotty pine is exactly like staining any other wood surface.
If this is an existing piece, remove the existing finish entirely. Sand the surface with 120-grit sandpaper. Wipe clean with a tack cloth.
With a foam brush, apply pickling stain to the knotty pine. Be sure to force the stain into all grains on the surface. Let the pickling stain sit on the surface for 5-minutes, wipe excess stain off with a clean rag. If any of the areas are not sufficiently stained, repeat the process. If the stain is exceptionally thick in any area, remove more stain as desired. Allow the stain to dry for 24 hours.
After the pickling stain has dried completely, apply 1-coat of polyurethane with a natural bristle brush. Allow the polyurethane to dry for 24 hours. Lightly sand the surface with 220-grit sandpaper. Apply another coat of polyurethane. Continue until the desired finish is achieved. Allow the final coat to dry at least 48 hours, and then enjoy your pickled knotty pine piece.