Oxalic Acid Crystals
Uses for oxalic acid
Dark Spots, tannin stains and discolouration of the wood surface are usually caused by moisture and is exacerbated when the moisture is contaminated with metal, such as iron and steel (especially on Oak & Idigbo). Despite that, this particular discolouration can be removed with oxalic acid cleaners.
Oxalic Acid can also be used to freshen wood colour if it has become lightly greyed due to external exposure to sun light. In the refinishing of wood furniture, oxalic acid for wood can be used after stripping to lighten and soften darker stained areas before refinishing. It can also be used as a rust remover and a stain remover in many other applications.
Just hearing the word "acid" sounds ominous and heavy duty, but oxalic acid cleaner is easy and safe to use in the home. In fact, it is found in many vegetables including spinach, and rhubarb and is also used in shampoo and washing powders.
Oxalic Acid for wood is supplied in crystal form and looks just like sugar. Our Oxalic Acid is a high commercial 99% + purity grade. Not all Oxalic Acid for sale is the same purity.
Simply mix with water in a clean container until you have a saturated solution (where there is a tiny bit of undissolved sediment at the bottom). Approx. 60 grams per litre of water. You then have a ready to use solution. Adding more Oxalic Acid crystals will not make the solution any stronger.
Methylated Spirits can also be used as an alternative to water. Using Methylated spirits allows for quicker drying, enabling a protective coating to be applied to the timber sooner, but keep in mind, do not breathe the fumes.
Apply the solution directly onto the timber with a brush. The bleaching process will continue for 1 - 2 hours, however, results can often be seen within 20-30 minutes. Multiple applications may be required to fully remove the staining. Once removed, the timber will need to be thoroughly cleaned with clean water or methylated spirits and then allowed to dry.
One kilogram of wood bleach Oxalic Acid will make approx 15-17 litres of ready-to-use solution.
Coverage is approx. 12sq meters per litre of solution (depending on the porosity of the timber)
A pre-mixed Oxalic Acid Wood Bleach is also available as a ready-to-use solution in 250ml, 500ml, 1L, 2.5L & 5L bottles.
Please note that any surface coating, such as a woodstain, paint, oil etc will prevent the oxalic acid solution from working, so all protective coatings will have to be removed prior to application.
Warning: Oxalic Acid is still an acid and should be treated with respect. In its purified form, oxalic acid is a highly corrosive and toxic substance. Latex gloves should be worn at all times when using it and it should always be mixed and used in a well-ventilated area.
Always protect your skin and wear a dust mask when mixing.
Container size: 1Kg, 5kg, 10Kg and 25kg.