The extremely durable, aesthetically appealing anodize finishes Linetec produces for your architectural aluminum products are achieved through a complex process. In the architectural finishing industry, it’s simply called “two-step electrolytic” because the anodizing and coloring occur in separate stages.

Before these two steps begin, your aluminum extrusions or sheets are carefully attached to racks. Our computer-controlled equipment guides your racked material through our completely automated anodize line as we monitor the progress with quality checkpoints along its journey.

For a deeper look into the anodize process, watch our 5-minute video, “How do they do that?

An integral part of the aluminum substrate, anodizing is the process of electrochemically controlling, accelerating and enhancing oxidation.

Step 1:

The anodizing step takes place in the first tank. It contains a sulfuric acid and water solution, charged with electrical current. This is known as an acid-etch process and is an environmentally responsible improvement to older caustic-etch processes.

The racked aluminum is submerged in the electrically charged anodize tank, which causes aluminum oxide to form on the metal’s surface. The oxide film is uniform, hard and protects the rest of the aluminum substrate from deterioration.

The hardness of the anodized surface is comparable to a sapphire – the second-hardest substance on Earth. Anodized aluminum resists the ravages of time, temperature, corrosion, humidity and warping, adding to its long life. It is an inert material that is not combustible, 100% recyclable and poses no health risks.

After Step 1, a Clear Anodize finish highlights the aluminum’s natural, silver color. If other metallic tones are specified, the racked aluminum continues to Step 2.

Step 2:

In the coloring tank, the anodized aluminum is immersed in a bath containing an inorganic metal, such as tin, cobalt or nickel. The metal deposits in the anodic pores by means of electrolytic current. Different colors result depending on the type of metal and the length that the aluminum soaks in the bath. Darker colors are created by extending the immersion time and increasing metal deposition.

From light to dark, our standard anodize colors are:

  • Clear
  • Champagne
  • Light Bronze
  • Medium Bronze
  • Dark Bronze
  • Extra-Dark Bronze
  • Black

Expanding the traditional color palette for anodized aluminum, our proprietary Copper Anodize and Bordeaux Anodize finishes are achieved with a bath of tin in Step 2 and a unique third step.

Linetec Copper Anodize
Specialty Step 3:

Extending the electrolytic coloring process, our specialty Step 3 soaks the anodized and tin-colored aluminum in a bath of copper. Linetec’s custom formulation creates the precise balance to produce these luxurious elemental and burgundy tones. While real copper is used, the anodize finish produced will not develop a green patina as it ages or leave run-off stains on adjacent materials.

Whether Copper or Champagne, no clear coat is required to preserve the anodized aluminum’s metallic color or to improve the finish’s performance. Linetec’s eco-friendly anodize process meets or exceeds all AAMA 611 specifications, and is supported with a standard warranty of five years with optional extended 10-year warranty available.

For personalized service with your next anodize order, please let us know how we can be of assistance.