No one wants to live in a cave for a home. Dark hardwood floors, deep-colored woodwork, too-intense wood wall paneling – if your home is consumed with dark colors, it can create a dingy, dark effect. Bleaching may be the solution to brighten a room.
Sanding simply won’t help. It removes the finish, but does nothing to lighten the color itself. The same is true with pet urine stains, ink splatters, coffee spills, water marks and other blemishes that have a tendency to occur. If the stain soaks into the wood, without sanding very deeply, you won’t get it out. Unless you use bleach. You simply need to know when and how to use it.
Choosing a Wood Bleach
Bleaching, the chemical process that removes color – is something of an art and a little bit of science. First, there are the chemicals that create the bleaches. Bleaches require neutralization with other substances to end the bleaching process. You also have to judge when the bleach has reached a point where it can do no more, know how to strip a finish (and how to reapply when you’re done), and which bleach will perform best to give the effect you want.
It’s also important to know which species of wood will react to which bleach in what manner. But ultimately you don’t have to become an expert on bleach. Instead you can test the bleach in an inconspicuous spot and use your best judgment from there. None of it’s truly complicated, once you understand your bleaches.
Chlorine bleaches are the mildest form of wood bleach. Liquid chlorine bleach (laundry bleach) is even gentler than swimming pool chlorine (calcium hypochlorite). Use chlorine bleaches to lighten or remove stains on any wood surface. Stains that respond to chlorine bleaching include most dyes, as well as organic stains such as blood, food, and drinks. Expect to apply more than one treatment for most stains.
Oxalic acid is much stronger than chlorine bleaches. Rust and iron stains on wood are no match for it, nor are water stains (which are actually iron stains from the trace iron in most tap water. The iron reacts to the wood tannins, causing the telltale black spots). Oxalic acid also works on most inks except India ink. More than one application may be needed to remove the stain involved.
Two-part bleaches are a little different. First, it has two components that, when combined, create the bleaching effect. More significantly, while you can definitely remove stains with a two-part bleach, you’ll probably end up with paler wood as well. Two-part bleaches are the only bleaching product that will lighten nearly any wood – it actually removes the wood’s color. Read and follow the manufacturer’s instructions closely when using a two-part bleach to ensure best results.
How To Use Wood Bleach
Doors, floors, wood trim, kitchen cabinets, mantle, or dining room table – if it’s wood, you can bleach it. Once you know which bleach to use (or starting with the most gentle and proceeding to the strongest, if you haven’t a clue what created the stain), the actual bleaching process is almost obvious.
• Open windows or turn on fans to allow plenty of ventilation while you work.
• Use synthetic brushes and wear protective eye glasses, a dust mask or respirator, and gloves, particularly when mixing or applying bleaches.
• Keep a container of the bleach neutralizer nearby while working. Use in case of emergency. (See the step on neutralizing for further information.)
• Wash hands immediately after you leave the work area, even if you plan to return immediately.
• Lay plastic around the work area if you must work inside. Cover anything that may get splattered or splotched with bleach – plastic sheeting works best. Spread extra plastic for a walkway, so you don’t get bleach on your shoes and spread it throughout the house.
• Strip the existing wood finish. Remove paint and typical wood finishes either by sanding or applying the appropriate solvent: Lacquer thinner attacks lacquer finishes, which are a very popular floor finish today. Denatured alcohol helps dissolve shellac. Paint and varnish removers work on most of the remaining types of finishes. Apply as directed, either soaking paper towels layered over the wood and allowing it time to work or, in most cases, brushing it on. Once the finish is soft, use a plastic scraper to gently scrape it away. Clean the scraper often and avoid gouging the wood.
• Sand the wood once the stripper is dry and most of the finish is removed. Use coarse grit to start, ending with a finer grade such as 120-grit. Aim to smooth the wood surface as well as to remove any trace of remaining finish.
• Neutralize any chemicals remaining in the wood. Fill a bucket or large bowl with hot water and add washing soda (sometimes called sal soda – you can find it with the laundry products in your local supermarket). Follow product instructions for the proper amount to use. Rinse the wood, using a rag, and allow it to dry.
• Pour liquid chlorine in a bowl or spray bottle (avoid exposing any bleach to metal). Mix swimming pool chlorine with hot water to create a thick liquid or a thin paste. Dissolve oxalic acid in hot water until saturated, meaning no more will dissolve. Follow the manufacturer’s instructions regarding two-part bleaches.
• Paint, spray or rub on the bleach as appropriate. Work from the bottom up on vertical surfaces. Apply even coats and cover with damp paper towels to delay the dry time if it begins to dry before you are finished with the entire section.
• Wait at least 30 minutes, or as the product directs, before judging the results. Re-cover and wait another 30 minutes, maximum, if needed. Otherwise, mop up any bleach still pooled on the surface with soft cloths, discarding them when you’re finished.
• Rinse the wood with distilled water. Avoid tap water to prevent water stains from the iron content. Avoid allowing the rinse water to spread to unbleached items or areas.
• Apply a neutralizer to stop any further bleaching. Both chlorine bleaches and two-part bleaches require a weak solution such as a mixture of half water and half vinegar. Oxalic acid, on the other hand, is neutralized with a solution of 2 T. baking soda dissolved in a quart of water (double the recipe as needed).
• Sand the wood again once the wood is dry – typically 24 to 48 hours later. Use 120-grit to start and increase the grit as desired. Alternatively, apply a thin layer of lacquer and sand it off instead. Either process allows you to smooth the wood fiber edges which roughed up during bleaching.
• Refinish your wood as desired.
If, after all your efforts, the stain remains or the wood isn’t quite the color you wanted, you may need to readjust your wishes. Some stains may never go away without sanding – and you may not want to sand that deeply.
All woods are not the same. What one will tolerate, another may not. This makes testing bleaches on scrap wood a good idea, and serves as a caution that if over-bleached, some wood may react badly. Use your bleach wisely and know when to say enough.