Rack Anodizing

Seidel exclusively offers rack anodizing with all racks made from titanium, specifically designed in-house to exceed all anodizing standards. Each component is individually loaded onto racks to allow for proper contact, which results in better quality parts. Each rack is transferred through approximately 30 processing tanks. The fully automated and tightly controlled process takes about 2 hours and the principal steps are listed below…

Rack Anodizing Process overview

Loading on Racks

Each part is affixed on rack pins (manually or automatically)
Racks are made of titanium
Approximate rack size : 11.5 ft * 3.5 ft
Depending on part size, each rack holds
between 20-12,000 parts

Electro-polishing

Applying up to 10,000 Amps per rack dissolves the “tips of the mountains” on the surface of the aluminum
The result is a shiny finish on high purity aluminum (5657 alloy) or satin finish on low purity aluminum (e.g. 3005 or 9020 alloy)
The metal removal is tightly
controlled (about 1 mil or
25 micro-meter)

Etching

Parts are exposed to an alkaline solution which etches away the surface
Result is a matte finish

Anodizing (anodic oxidizing)

Aluminum creates on its surface a natural aluminum oxide (AI2O3), which protects the aluminum from disintegrating. Using these natural properties of the aluminum we increase the thickness of the AI2O3 in the anodizing process. This layer provides additional protection against corrosion and a surface which can be colored with dye

Additional technical information about the aluminum oxide:
    • hardness comparable to a diamond
           . diameter of the pores: 1/10 of the wavelength of light
          . thickness of AI2O3: from 2 to 25 micro-meter (80 micro-in to 1/1000 in)
    • enhanced abrasion resistance
    • pores can absorb dye coloring
         . the pores are 1000 times longer than they are wide
         . up to 400 billion pores/in2

The pores are extremely hard, non-conductive, corrosion resistant, abrasion resistant and transparent
Temperature controlled environmental conditions are essential to achieve consistency

Dyeing

The pores created in the anodizing process are now ready to absorb organic dyes. These dyes will be absorbed and integrated into the aluminum oxide and cannot be scratched off like paint.

Extreme close up of the porous layer of oxide.

Sealing

Seidel uses a proprietary hot water seal which closes the pores of the aluminum and traps the dye in the metal
We do not use nickel acetate seal for environmental reasons

Drying

Parts are dried with hot air in multiple convection ovens