News

Guide to metal finishes: Processes and benefits for metal

Do you know the difference between anodising and galvanising? Powder coating and perforating? There are many types of metal finishes, and understanding the benefits of each is key to ensuring the right end result.

Metal finishing is simply the final process for metal sheets and panels, which alters the surface to create varied looks, brightness, colours and textures. Some finishes can also help improve durability and resistance to corrosion and wear.

From mechanical process finishes such as such as grinding, perforating and buff polishing to chemical finishes including anodising and galvanising, here’s a handy guide to the most common types of metal finishes, their processes and benefits for your specified material:

Metal finish: Perforated

Perforated metal finish process: Perforating is the process of manually and mechanically stamping or punching metal to create a pattern of holes, squares, slots or decorative shapes. Perforated metal sheets can be made from stainless steel, steel, aluminium, brass, copper and other metals.

The advantages of perforating metal:

• Perforated metal sheets allow light and air to travel through
• If equipped with a sound absorbing lining, perforated metal can work well as an interior acoustic solution
• Extensive choice of perforation pattern including custom-created designs for bespoke architectural uses

Metal finish: Anodised

Anodised metal process: Anodising is the process of increasing the thickness of the metal’s natural oxide layer, increasing durability. There are various types of anodising depending on the types of acids used for the process. Although anodising can be done on other metal, it is most commonly used on aluminium.

The advantages of anodising metal:

• Anodised aluminium is hard, durable and weather resistant
• The anodised coating is integral to the metal and cannot peel or flake
• Anodising helps increase adhesion for paint and primers
• Colours can be added during the anodising process, making it a more durable option for metal colouring

Metal finish: Galvanised

Galvanised metal process: Galvanising is the process of applying a protective zinc coating to steel or iron. The most common method is hot-dip galvanising, in which the metal is submerged in a bath of molten zinc. Hot Dip Galvanizing takes place after a product has been manufactured, so that all the edges of the material are protected by the coating.

The advantages of galvanising metal:

• Galvanising provides a protective coating to help prevent rust
• Galvanising helps prolong the service life of the metal material

Galvanising is not ideal for perforated metal, as it can cause distortion and the zinc can fill the holes. At Arrow Metal galvanising is recommend mainly for solid metal panels and structural frames.

Metal finish: Powder coated

Powder coated metal process: Powder coating is the process of using paint powder and applying it to metal electrostatically. It is then cured under heat to allow it to form a hard, coloured skin. Powder coating is used predominantly to create a decorative coloured surface for metal.

The advantages of powder coating metal:

• Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging
• Powder coated metal generally retain its colours and appearance longer than liquid coated metal
• It gives metal a wide range of special effects that would be impossible to achieve with other coating process
• Compared to liquid coating, powder coating is more environmentally friendly as it emits near zero volatile organic compounds (VOC)  into the atmosphere

Powder coating isn’t suited to all metals however. It does have some porosity, which makes it insufficient as a protective coating for ferrous metals used in external environments.