Teak is a popular, light brown hardwood used for making things like patio furniture and boat decks. And bleaching it is a viable way to lighten its color or conceal water stains. You will need a number of chemical supplies and a bit of patience, but the process will help give your wood the look you desire.
Things You'll Need
Liquid laundry detergent
Bronze wool pad
Oxalic acid based cleaner
Hydrochloric acid based cleaner
Wash the teak surface thoroughly with a mild cleaning solution made from warm water and liquid detergent or multipurpose cleaner. Scrub the teak with a scrub pad or a sponge soaked in the cleaning solution. Then rinse with cold water and allow the teak to dry completely. This prepares the wood for the bleaching process.
Make another solution, this time mixing three parts liquid laundry detergent with two parts chlorine bleach. Stir thoroughly before using, so the laundry detergent and the bleach are completely mixed together.
Scrub the teak with a stiff brush soaked in the chlorine solution, while wearing latex gloves to protect your hands. Apply the solution to the surface of the teak generously, leaving it on the wood for a few minutes, allowing the detergent to repel the dirt and the bleach to lighten the texture. Then treat the teak with the brush, scrubbing along the pattern and the grain.
Wait for the teak to dry, because only then can you see its true color.
If the teak is still too dark or the water damage is still visible, apply an oxalic acid based cleaner to your teak, using a strong, bronze wool pad or similar abrasive pad. Avoid using a steel wool pad because it will leave rust freckles behind. Spread the cleaner to the teak surface evenly and in a rich lather. Then allow it to sit a few minutes on the wood and work its way into the grain.
Rinse the wood with water. Use a dry, soft cloth to wipe it off, then leave it to dry thoroughly. Check the color and the look of your teak wood. If you are still not satisfied, try using a strong, hydrochloric acid based cleaner.
Check if the chlorine bleach you are using contains trisodium phosphate, since that is the most suitable type of bleach when it comes to treating teak.
The best type of scrub brushes to use are those with soft nylon bristles.
Use a loose piece of teak as a test before bleaching your furniture or boat, and note how much of each chemical you used to get the desired look.
Work with small amounts of each chemical, as it's much easier to gradually lighten than to try and make it darker again.
Wear protective latex gloves when working with bleach and other chemicals.