Oxalic Acid Crystals
Water and methylated spirit soluble oxalic acid crystals used extensively as a wood bleacher.
Oxalic acid will lighten or eliminate water, ink, alcohol and mildew stains on new or stripped timber.
Will also lighten the wood itself in varying degrees.Dark spots and discoloration of the wood surface are usually caused by water spots and may be lightened or removed with oxalic acid. Oxalic acid is also used to freshen wood color if it has become grayed.
Add 4-8 tablespoons of oxalic acid crystals in a heat resistant glass jar to one litre hot water. The general rule is to make a "saturated" solution - ie to have some undissolved crystals left at the bottom of the jar after mixing.
Apply this solution to the surface evenly with a cloth, sponge, or brush. Do not apply just to the discoloured area or there will be light spots left. Leave to dry - there may be small crystals reappearing when the water has evaporated. If the stain remains, dab more solution onto the stained area only. Continue to apply until desired color is obtained.
Solubility in water :
- 95 grams per litre @ 15oC
- 140 grams per litre @ 25oC
- 1200 grams per litre @ 100oC
To neutralize the residual acid (stop bleaching action), wash the surface with a weak solution of 1 tablespoon clear ammonia to 1 litre of water. If clear ammonia is not available, wash with a solution of 2 tablespoons borax dissolved in 1/2 litre of water. Rinse with clear water and wipe with a dry cloth. Remember that water will raise the grain of the wood. Let dry 12 hours or more before sanding. Sand down the raised grain with a good quality medium grade finishing paper (eg P120-180) or any wood stain applied will be darker in the raised grain area.
Poisonous - Keep Out Of reach Of Children
Harmful by inhalation or through absorbtion through the skin.
Wear suitable gloves and eye protection at all times when handling this product.
*Note : Picture for illustration only, product is supplied in heavy duty resealable plastic bags.