Get the Color Out With Wood Bleach

When it comes to altering the color of wood, woodworkers routinely turn to stains to give wood more-or a slightly different-color. But wood bleach lets you remove color from wood.

You'll find three kinds of products marketed as wood bleaches. But only one will remove the natural color from wood: a two-part wood bleach of sodium hydroxide (caustic soda) and hydrogen peroxide. Other wood bleaches are chlorine bleach and oxalic acid.

Chlorine bleach, which is like ordinary laundry bleach, will remove dye color from wood, but not the wood's natural color. Oxalic acid is commonly employed to bleach out water or rust stains. Teak stain remover sold by boat dealers is often based on oxalic acid.

All the bleaching chemicals pose health and safety hazards to varying degrees. So be sure to read the manufacturer's instructions and warnings before use. And always wear rubber gloves and eye protection around bleaches.

The Wood-Kote brand bleach we tried comes, like most, in two bottles. To use it, mix equal parts of the two liquids in a glass or plastic container. Never put either chemical into a metal vessel. (Some bleaches call for applying the two parts separately. Follow the instructions for the one you're using.)

Once mixed, a chemical reaction begins, wherein the hydrogen peroxide, an oxidizer, acts to neutralize the caustic sodium hydroxide. Neutralized, the solution loses its bleaching power, so mix only what you can use immediately.

Quickly apply the solution to the wood. A sponge makes a good applicator. Keep the surface uniformly wet to minimize streaking. (We held the board at an angle and worked from the bottom up.)

Rinse the solution off the wood with water. To ensure that no caustic soda remains behind, rinse the wood with a mild acid-white vinegar works well-then rinse it once more with water.

After the wood dries, assess the color. You can bleach wood as many times as needed to achieve the color you want. (We bleached the pale piece of red oak in the top photo, and made three applications to the walnut sample.)

Allow the wood to dry thoroughly. Sand with 320- or 400-grit sandpaper, just enough to remove the fuzzy grain from the surface.

• When the wood you have is too dark for a particular project. In this case, removing some of the color from the wood might make it more suitable, or would allow you to stain the wood to a lighter color.
• When you have several boards of the same wood for one project and they vary in color. In this case, you can bleach one or more of the boards to match the others. Or, you might bleach all the boards and stain them to a consistent color.
• When you want to stain one wood to look like another. Removing the natural color from a wood makes matching the color of another wood easier. If you bleach both woods, you can stain them both the same color.