Tips and Tricks For Painting Aluminum
Aluminum does not need a protective layer but can be painted like almost any other metal. When painting, however, you should pay attention to the special features of aluminum, especially the oxide layer.
Aluminum cannot rust like iron or steel and therefore does not need a protective coating against corrosion. As a non-ferrous metal, aluminum such as brass or copper quickly forms a protective oxide layer on the surface after contact with air, which protects the metal underneath. Good for aluminum, bad for painting. Because of this layer, paint adheres much more poorly to aluminum than to iron or steel and often flakes off again after a short time.
Why do you paint aluminum?
Whether model builders, car and classic car fans, or gardeners, the Beautify flower potswant: If you want to paint aluminum, you usually do it for decorative reasons. Special corrosion protection is not necessary for aluminum in the hobby or private sector, as it will hardly come into contact with aggressive substances.
What should you watch out for when painting aluminum?
First of all, you should know whether your workpiece is made of untreated aluminum or anodized aluminum. Anodized aluminum has an electrically hardened surface with an extremely robust oxide layer as corrosion protection, which forms out of the aluminum itself. A porous layer forms on this layer, which does not adhere well to the aluminum oxide underneath, so that the paint flakes off again. Before painting, you have to remove the electrically burnt-in oxide layer, which can only be achieved with sandblasting or very aggressive chemicals and is, therefore, a matter for specialist companies.
Which paint for aluminum?
Since the paint does not adhere directly to the metal, but to the primer, the type of paint is not that important. It must be suitable for metal. The composition is more important: there are one-component and two-component paints, visit for more details. A one-component paint is a basecoat and dries through evaporation of the solvent. A two-component paint is more robust and a mix of paint and hardener; it dries after a chemical reaction and has a sealed surface. A 2-component paint can be colored or clear. You should not paint over a colored 2-component lacquer with clear lacquer – if the surface should shine, take a 1-component basecoat and protect it with a 2-component clear lacquer. To paint aluminum, you can paint the paint with a brush, apply a small paint roller or apply it with a spray can.
Instructions for painting aluminum with basecoat and topcoat
- Sanding (grease, no heading)
Back up the oxide with 400 grit sandpaper and then smooth the aluminum surface with fine 1000 grit sandpaper.
The surface must be clean and free of grease before painting. Remove sanding dust whose grains can later be seen in the paint. Clean the aluminum with alcohol or grease cleaner and then no longer touch it with your bare fingers.
- Apply primer
Apply the primer crosswise and let it dry. You can spray or brush on the primer.
Apply the topcoat crosswise from the spray can or with a paint roller. It is better to paint in several thin layers instead of one thick layer of paint.
Apply the topcoat for sealing and ensure that the colors of the two products are compatible with each other. With two-component paints, the seal is included.