In rare cases, we receive feedback that stains are visible on our aluminium profiles. We are talking here about “tarnishing of the mounting rails”.

This is not visually appealing. The reason for this is almost always improper storage of our aluminium profiles or incorrect processing. However, this can be avoided relatively easily. Below, we explain what corrosion is in aluminium, what advantages it brings and how you can avoid corrosion-related stains.

Why do aluminium profiles corrode and how can this be prevented?

Aluminium corrodes due to natural environmental influences, in particular electrochemical reactions. Corrosion can convert the surface of aluminium into metal oxide. This occurs when aluminium rails are stored outdoors without protection and are therefore exposed to wind, weather and, in particular, moisture.

Perhaps not visually appealing – but technically no problem at all

An oxidised aluminium surface has no negative technical impact on the stability or service life of aluminium profiles. On the contrary, it actually makes the surface more stable and acts as a protective layer.

Corrosion occurs when aluminium comes into contact with water and oxygen. In this case, iron begins to rust and copper turns green.

Aluminium forms an oxide layer which, if it is even and closed, ensures that corrosion does not continue beneath this layer. This can cause the aluminium to turn white. This phenomenon is also known as “white rust”. However, this term is misleading. “White rust” has nothing to do with the rust we commonly know; rather, the layer that forms has a protective function. It therefore has exactly the opposite effect to a layer of rust.

Because aluminium is corrosion-resistant.

Avoid stains and store and process correctly
Even though tarnished or corroded rails do not pose any technical problems, how can you still avoid this discolouration?

We always store our profiles indoors so that they are not exposed to the elements. We also load the lorries in a covered area. We have agreements with our transport companies that our aluminium profiles should only be handled in dry conditions.

We recommend installing aluminium profiles as soon as possible after receipt. If this is not possible, it is advisable to store the profiles in a dry place (indoors) at a constant temperature with adequate ventilation and to remove any transport film to prevent staining.

Aluminium is a good heat conductor, often feels cold to the touch and attracts moisture, which can accumulate in certain areas under the film. If there is insufficient ventilation between the profiles – meaning that the moisture cannot evaporate – corrosion will occur. If the profiles are still protected by film, this corrosion will only occur in certain areas. This will then lead to the formation of unwanted stains.