1.

The first step is the  pre-treatment with cleaning and making the aluminium profiles ready. The profiles are etched in an alcaline bath for a certain period of time, a bath which is based on sodium dioxide. Then the profiles are rinsed in order to remove any possible deposits. In connection with the pre-treatment special mechanical or chemical treatments may also be carried out.

2.

The actual anodising is the second step in the process. Here the profiles are lowered into an electrolyte bath, which is usually based on sulphuric acid. After anodising the microscopic pores in the anodising layer are still open.

3.

The aluminium is now ready for colour anodising, which is the third step in the process. This step is optional. Colour anodising may be done either by lowering aluminium into a dye bath or by means of electrolytic colouring. This is carried out by lowering the aluminium into a bath with a colour solution and then induce a DC current.

4.

The fourth step in the anodising processs is sealing the surface. In order to obtain a fully protected surface the oxide layer must always be sealed. This is done by lowering the aluminium into a bath with boiling water.