Colours and Finish

Painted aluminum profile surfaces

The appearance of painted aluminum profiles is evaluated on the requirement surface.

The critical surface area refers to the part of the total surface area that is essential to the appearance and usability of the product. Edges, deep pockets, and secondary surfaces (hidden surfaces) should not be included as critical surface areas. The appearance of the critical surface area must not have any scratches down to the base metal. When the coating on the requirement surface is viewed at an angle of approximately 60 degrees to the upper surface, none of the defects listed below may be visible from a distance of 3 meters: excessive roughness, streaks, blisters, inclusions, craters, dull spots, small holes, pits, scratches, or other unacceptable defects. The coating must be uniform in color and gloss with good coverage. There are no requirements for hidden surfaces.

Anodizing

Anodizing is the strongest surface treatment available for aluminum profiles. It is an electrolytic process in which an oxide layer is built up. The most common form of anodizing is natural anodizing. The process usually consists of four steps: pre-treatment, the anodizing itself, coloring (if applicable), and post-treatment. Once the metal surface has undergone the desired mechanical or chemical pre-treatment and has been thoroughly cleaned, the electrolytic process takes place. Direct current is connected to the profile, which becomes the anode (hence anodizing). An electrolytic cell is formed. The electrolyte usually consists of diluted sulfuric acid at room temperature. The oxide layer formed contains a large number of pores with a diameter between 0.02 and 0.1 µm. To obtain a dense surface layer, the pores must be closed. This is done by post-sealing—treatment in 95-100 degree deionized water. This converts the aluminum oxide to boehmite, increasing the volume and closing the pores. The oxide layer formed during natural anodizing is transparent. The naturally anodized profile is supplied with a matte surface as standard.

Dyeing

Naturally anodized with unsealed aluminum is colored with organic or inorganic dyes. After coloring, the oxide layer is sealed.

Electrolytic coloring in brown scale Hx

Similar to the simple coloring process, coloring is done in a separate step after anodizing. Through the action of alternating current, the pigments, which consist of tin salt, are deposited at the bottom of the pores. The color scale ranges from sepia to black. The colors, designated Hx-5 to Hx-50, have very good color fastness.

Quality assurance

Aluminum profiles surface treated with Natur or Hx anodizing method according to SS-EN ISO 7599:2018. The standard defines sealing, abrasion, corrosion, gloss, and light resistance. The standard also specifies requirements for performing inspections and the test methods to be used.

Surface treatment

Painting & anodizing

Varnishing

Painting offers an unlimited choice of colors with excellent color matching. Powder coating is by far the most common painting method today.

Sapa Building Systems' profiles undergo nine steps before painting:

Alkaline washing
Rinsing
Pickling
Rinsing
Deoxidation
Rinsing
Chromating
Rinsing
Drying

Pre-treatment

To achieve the right quality on the painted surface, it is important that the pre-treatment, application of the paint, and subsequent curing are carried out correctly. Pre-treatment is crucial to achieve maximum adhesion and durability. It normally consists of degreasing and pickling the surface, followed by a chrome-free chemical treatment. The pre-treatment is completed by rinsing the profiles in deionized water. Pre-treatment provides the best possible corrosion resistance and adhesion when painting products that are to be used outdoors.

Painting

The pre-treated profile is covered with polyester powder. The powder, polyester, is applied to the profile by electrostatic or friction charging, after which the powder is cured in an oven at 180ºC. Powder coatings are applied and cured without any solvents. The ventilation air from the powder application is purified in efficient purification plants. Powder that “misses” the profiles is collected in a recycling system and returned to the spray gun.

Inspection

Inspection is carried out at a viewing distance of 3 m, in normal daylight without direct sunlight or with interior lighting of 600-1000 lux. The profile surface should be viewed for 5-10 seconds. Impurities and other defects that are not clearly visible in normal daylight from this distance are not valid grounds for complaint and compensation.

Sustainability

Hydro CIRCAL®

Our strong commitment to sustainability is reflected in the use of recycled, low-carbon aluminium from Hydro in all of our products as standard. This approach brings a unique and meaningful response to the growing demand for environmentally responsible building materials.

95% recyclable

Our solutions are 95% recyclable. When we design our products, we act for circularity by taking into account their disassembly and re-use at the end of their life.

75% recycled

Our solutions are made with at least 75% of recycled components including aluminium, EPDM, polyamide.

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