How to Bleach Wood Furniture
Bleaching wood furniture lightens the overall color of the wood, giving it a clean, bright look. While bleaching isn't intended for removing stains, it will proportionally lighten the stains and reduce their visual impact. Bleach wood furniture to help restore it to a fresh, natural appearance for subsequent clear coating or staining.
What is Wood Bleaching?
Bleaching chemically degrades the oils in the wood that influence the color, thus lightening the wood or eliminating the color completely.
3 Ways to Bleach Wood Furniture
For a bleaching agent for your wood furniture, choose one that's mild, moderate, or strong: laundry bleach, oxalic acid, or two-part bleach.
Common household laundry bleach can be used at full strength to bleach wood. Your mildest option, laundry bleach will minimally lighten wood on the first pass, so several applications are needed
At $6 to $10 per gallon, household chlorine bleach is your best bet for saving money and for lightening the wood in less dramatic increments than with other methods.
Oxalic acid, an organic substance, is a powder or crystal that mixes up with hot water to create an effective overall wood bleaching solution. Oxalic acid can also be mixed with a small amount of water to create a paste for spot-lightening stains and blemishes.
Oxalic acid costs about $14 to $16 per gallon, after diluting with water.
Two-Part (A/B) Bleach
Also called A/B bleach, two-part bleach uses two solutions—sodium hydroxide and hydrogen peroxide—that are mixed to create a very strong solution. Two-part bleaches work well with heavily tannic woods, dark woods that need to be turned light, and with heavily stained or blemished woods.
Two-part bleaches can be prohibitively expensive. Two 1-gallon bottles, which must be purchased in tandem, cost over $100.
Observe safety precautions when handling chlorine bleach, oxalic acid, and two-part bleach. All substances are toxic and can be fatal if ingested.
What You'll Need
Equipment / Tools
- Synthetic-bristle paint brush
- Latex gloves
- Paint scraper or five-in-one tool
- Oscillating sander
- Putty knife
- Cotton rags
- Plastic dropcloth
- Tack cloth
- Glass container
- Breathing and eye protection
- 120-grit sandpaper
- Bleaching agent (Bleach, oxalic acid, or two-part bleach)
- Natural paint stripper
- White vinegar
Prepare Work Area
Work only in a well ventilated area. Working outside in the sunlight accelerates the bleaching action, plus it helps the wood dry out faster between coats. Lay down plastic below the wood furniture.
From paint strippers to bleaching agents, the ingredients used for bleaching wood furniture are toxic. Wear latex or latex-substitute waterproof gloves, eye protection, and breathing protection.
Remove Paint and Coatings From Furniture
Paint, stain, and other coatings on the wood act as barriers that prevent the bleaching agent from lightening the wood. Instead of using toxic paint strippers, try removing the coatings with non-toxic, less caustic citrus- or soy-based natural paint strippers or by scraping the wood while using a heat gun.
Sand the furniture thoroughly with 120 grit sandpaper to remove all coatings. Embedded stains and paints that were not removed by the paint stripper must be removed by sanding.
Clean Off Wood Dust
Clean the wood dust from the furniture with tack cloth.
Prepare Bleaching Solution
- Laundry bleach: Use laundry bleach at full strength, undiluted. Pour into a glass or plastic container, not a metal container.
- Oxalic acid: Dissolve 12 ounces of oxalic acid in 1 gallon of hot water. For smaller quantities, dissolve 3 ounces of oxalic acid in 32 ounces of hot water. Stir well since clumps of oxalic acid will lighten the wood in blotches.
- Two-part bleaches: In a glass or plastic container, mix one part of sodium hydroxide (Part A) to three parts of hydrogen peroxide (Part B). Do not add water.
Apply Bleaching Solution
Apply the bleaching solution to the furniture in a single coat. Avoid overlapping. Keep the brush continually moving. Apply the solution evenly across the entire piece. Do not apply more in one section than in other sections. On vertical surfaces, start at the bottom and work upward.
- Laundry bleach and oxalic acid: Use a sponge to apply a solution of one part white vinegar and one part cool water to neutralize the solution between coats.
- Two-part bleaches: Using a sponge, rinse with cool water between coats.
Apply Multiple Coats
Apply multiple coats of bleaching agent, interspersed with neutralizer or rinse, to achieve the level of desired wood lightness. Laundry bleach may require five or more coats to begin to lighten the wood.
Sand a final time with 120-grit paper, then switch to a finer grit, such as 220-grit sandpaper.
Avoid deep sanding after bleaching the wood as this removes the bleached wood cells and takes the surface back down to darker layers of wood.
When to Call a Professional
Cedar, chestnut, elm, redwood, and rosewood are difficult to bleach. Call a professional woodworker for help with lightening these wood species.
Occupational Health Guideline for Oxalic Acid. Centers For Disease Control