table of contents
- What is rust?
- Corrosion in aluminum
- Possible surface treatments
- Aluminum and ferrous metals
- Remove superficial rust
- frequently asked Questions
Aluminum is a light metal. It is often used as a building material or for garden furniture. The question is how resistant to corrosion it is. How is rust removed? You will find out in this post.
In a nutshell
- Aluminum cannot rust like iron
- oxidation in air takes place in a different way
- a superficial protective layer is formed
- this should not be removed
What is rust?
Rust forms on the surface of ferrous metals when they are 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 metal underneath from further corrosion. Iron oxide is orange, red, or brownish. Flash rust is easier to remove because it only rests on the surface.
Note: Iron not only reacts with oxygen and water, but also with acid.
Corrosion in aluminum
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 and form 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
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Anodizing: An airtight protective layer forms around the metal. It does this by accelerating and controlling natural oxidation. This process also protects foreign metals from corrosion that may have been used as an alloy.
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Paint: A thin layer of lacquer 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 powder coating is applied to the metal and then cured in an oven. Powder coatings are very tough, but not as smooth as paintwork.
If there are aluminum parts in the vicinity or even in contact with iron, the iron oxide can migrate to the light metal. Even then, however, it is only a superficial problem. The situation is different with alloys. Workpieces or garden furniture made of light metal can also rust.
Note: Care should also be taken when connecting aluminum parts with iron screws. These can cause corrosion.
Remove superficial rust
A light layer of rust or flash rust can also be used simple means remove. These should not attack the metal underneath. Otherwise corrosion can progress.
Suitable measures and means:
- firm cloth, possibly moistened (only effective with rust film)
- Wire brush and sandpaper (use both carefully)
- special cleaners for aluminum
Not suitable:
- Acids of all kinds (remove the iron oxide, but also the desired oxidation layer)
- mechanical processes that attack the metal
- Acid based home remedies
frequently asked Questions
The classic is stainless steel, which is a combination of iron and, for example, chrome. In addition, copper and zinc do not rust, although copper also reacts with the air in the form of verdigris.
With treated aluminum parts, it is sufficient to clean soiled areas with hot water and a little washing-up liquid. The same applies if the light metal is untreated. However, it should dry well afterwards and not come into contact with acidic or alkaline cleaning agents. Use any aggressive home remedies cautiously.
Then it has to be renewed. It's still easy with paints - with powder coating, it gets more difficult. If the natural oxidation layer of the aluminum is damaged, it only helps to wait until a new one has formed.
