Surface Treatment – Anodising or Powder Coating

Extrusion Bending Tips – Surface Treatment


Surface Treatment

Choosing the correct aluminium surface treatment can be a tricky question when designing for a project. Because the type of surface treatment can have a big impact on production and the final look of your product. Here we provide a quick break down of the 2 most common surface treatment options for curved aluminium extrusions and discuss their benefits.

Untreated surface

The first option would be using untreated aluminium. While in some cases using plain aluminium might be perfectly fine, there are reasons to treat the surface. Aluminium, like other metals, can corrode when left untreated. The surface reacts with water and air and breaks down, often as a fine powder. This can slowly wear down a part and make it structurally unsound. If kept in certain conditions this wont be a concern, but generally treating the section in some way is far better than simply leaving it untreated.

Options for surface treatment



Anodising aluminium extrusions for bending Anodising is an electrochemical process that converts the metal surface to create a durable and corrosion resistant oxide finish,  This surface is fully integrated with the aluminium profile and so cannot chip or peel. The created surface is very porous and allows for additional processes such as colouring. The surface must then be sealed to fill the pours and protect the piece.


  • Great Corrosion Resistance
  • Dirt Repellent
  • Touch Friendly
  • Easy Maintenance
  • Unique Anodised Look
  • Long Lasting


  • Gloss and Shade can vary depending on Alloy
  • Does not work on all Alloys
  • Susceptible to Acid (staining)
  • Colour matching between batches can be tricky


Powder Coating

Thin walled aluminium channel curved the hard way

Thin walled aluminium channel curved the hard way

Powder coating is a dry finishing process that has become extremely popular. Used as functional, protective and decorative finishes, powder coatings are available in an almost limitless range of colours, textures and finishes. The process involves applying a powder onto the aluminium extrusion while the extrusion is grounded. The coating is attracted to the grounded part and adheres long enough for the the part to be placed in an oven and the coating to be baked on and cured. Powder coating is a very waste-low process, as any coat not applied can be collected and used again. Colour matching powder coated parts is very simple, as the powder comes marked with a specific RAL code that is unique to that shade. Simply using the same RAL colour will result in the exact colour match. This means that in long run projects every batch will match exactly.


  • No Limit on Colour
  • Good Corrosion Resistance
  • Very east to Colour Match
  • All Alloys can be coated with any Colour and any Finish


  • Susceptible to chipping or scratches
  • Chips can allow corrosion in
  • Can Crack


Bending With Surface Treatment

To find out more about bending with a specific surface treatment, please refer to one of the following articles Bending Anodised Extrusions Bending Powder Coated Extrusions