Finishes

BLEACHING

Most hardwood species can be bleached to complement a decorative motif, but darker hardwoods like red oak, hickory and ash are particularly suited for this application. Bleached, antiqued, pickled and colored hardwoods are preferred for decorative applications like mouldings, mantels, paneling, chair rails and decorative millwork. Experts recommend that you avoid bleaching hardwood floors, however. This process often weakens wood fibers, making floors more susceptible to the wear of regular foot traffic (For more information, see Quick Tips below).

The preferred method for bleaching hardwoods is a two-step process:

1. Brushing the wood with caustic soda or ammonia; and
2. Applying hydrogen peroxide.

In the first step, apply the caustic soda solution with a synthetic brush, evenly and liberally in the direction of the grain. Let the solution set for 10-20 minutes. The longer the set time, the whiter your wood will be. Do NOT let the caustic soda set for more than 20 minutes, however, because it will cause uneven bleaching.

Next, use a clean synthetic brush to apply the hydrogen peroxide. A foaming action will take place as the two solutions react. This is the actual bleaching process, and usually takes 30 minutes to an hour to complete. If the wood is not white enough apply the hydrogen peroxide again.

When the wood is sufficiently bleached, wash it down with clean running water, using a brush to supplement chemical removal. Dry the hardwood with paper towels and repeat the rinsing process again in 20 minutes. Rinse out all traces of the bleach or you'll experience problems when finishing. Let the wood dry in a well-ventilated area for at least 24 hours. Do not dry the material in direct sunlight, since this will intensify the bleaching process and lead to uneven coloring.

Preparing Bleached Woods for Finishing.

Bleaching causes the wood grain to rise. Smooth the surface again with a 180 grit sandpaper, and wipe away the sanding residue. Now the wood is ready for sealing (if you plan to leave it bleached), or for antiquing, pickling or coloring.