Aluminum is a light metal. It is often used as a building material or for garden furniture. The question is how corrosion resistant it is. How is rust removed? You can find out in this article.

In a nutshell

  • Aluminum cannot rust like iron
  • oxidation in air occurs in a different way
  • a superficial protective layer forms
  • this should not be removed

What is rust?

Rust forms on the surface of ferrous metals when exposed to moisture. Another word for it is iron oxide, because the iron reacts with the oxygen in the air. The rust does not form a closed surface and therefore does not protect the underlying metal from further corrosion. Iron oxide is orange, red, or tan. Flash rust is easier to remove because it is only on the surface.

Notice: Iron reacts not only with oxygen and water, but also with acid.

Aluminum corrosion

The light metal also reacts with the air, but in a different way than iron. Aluminum can therefore rust, but no deep corrosion layer forms. Only the outermost atoms of the aluminum react with the air, forming a very thin, barely visible layer. In contrast to iron oxide, it is rather whitish. This layer protects the underlying metal from further corrosion. For this reason, the layer should not be removed from untreated aluminum components.

Possible surface treatments

  • anodizing: This forms an airtight protective layer around the metal. It does this by accelerating and controlling natural oxidation. Furthermore, this process protects foreign metals from corrosion that may have been used as an alloy.
  • Paint: A thin layer of paint is applied to the light metal, which protects it all around against environmental influences. The advantage of the lacquer layer is that different colors are possible. A layer of paint can be damaged and may have to be renewed as a result.
  • powder coating: A powdered coating is applied to the metal and then cured in an oven. Powder coatings are very durable, but not as smooth as paint.

Aluminum and ferrous metals

If aluminum parts are close by or even come into contact with iron, the iron oxide can migrate to the light metal. However, this is only a superficial problem. The situation is different with alloys. Workpieces or garden furniture made of light metal can also rust.

Notice: Care should also be taken when joining aluminum parts with iron bolts. These can cause corrosion.

Remove superficial rust

A light layer of rust or rust film can be removed with simple means. These should not attack the underlying metal. Otherwise corrosion can progress.

Suitable measures and means:

  • firm cloth, possibly moistened (only effective for rust film)
  • Wire brush and sandpaper (use both carefully)
  • special cleaners for aluminum

Not suitable:

  • Acids of all kinds (although they remove the iron oxide, they also remove the desired oxidation layer)
  • mechanical processes that attack the metal
  • Acid-based home remedies

frequently asked Questions

What other metals don't rust?

The classic is stainless steel, which is a combination of iron and chrome, for example. In addition, copper and zinc do not rust, although copper reacts with the air in the form of verdigris.

How is aluminum maintained?

In the case of treated aluminum parts, it is sufficient to clean dirty areas with hot water and a little washing-up liquid. The same applies if the light metal is untreated. However, it should then dry well and not come into contact with acidic or alkaline cleaning agents. Use aggressive home remedies carefully.

What to do if the aluminum coating is damaged?

Then it must be renewed. With paint it's still easy - with a powder coating it's more difficult. If the aluminum's natural oxidation layer is damaged, the only solution is to wait until a new one has formed.

Category:

Garden maintenance