Fibreglass Cleaning

The oxalic acid is a weak organic acid, widely used in certain types of cleaning, especially for the removal of oxides from metal parts and parts made with fibreglass such as boats, surfboards and bathtubs. In the case of boat hulls it has also proven to be an excellent cleaner of algae and other encrustations on the boat.


Oxalic acid is a white powdered chemical. It is commercially available in di-hydrated form, which makes the powder somewhat wetted.

oxalic acid fibreglass cleaning

Oxalic acid is sometimes found commercially in solution. This is just a solution of oxalic acid in water, usually at 10% (100 grams of oxalic acid per litre of water), which is the proportion in which it is used for cleaning. In Alquera you find oxalic acid powder. It is then easy to make a solution by mixing 100 grams of oxalic acid per 1 litre of water.



fibreglass rust cleaning

  • Clean the entire rusty area with your usual cleaner or, failing that, with soap and water to remove the grease.
  • Make a solution of 100 grams of oxalic acid per litre of hot (not boiling) water. The hot water will simply facilitate the dissolution of oxalic acid in the water.
  • Apply the solution to the rust stains with a cloth. It is necessary to use gloves for this step.
  • Leave to act 1-2 hours
  • Rub the treated area with a damp cloth. The rust should come off by itself.
  • Rinse the entire area where you have applied the acid thoroughly with water.


cleaning algae on boats

  • Oxalic acid is one of the most effective solutions for cleaning algae and micro-organisms from ships.
  • The way forward is to create a solution of the acid and hot water, which will dissolve the acid powder. The hot water will encourage the acid to dissolve.
  • In this case, the best way to apply the acid and water solution is to use a spraying machine (such as those commonly used in gardens), which can make the work easier.
  • Cover the entire area to be treated with the solution and let it soak for about twenty minutes before rinsing. When you apply the sprayer you will see the stains begin to dissolve.
  • After 20 minutes rinse the entire area that has been covered with the acid solution with water.

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