Capalex Aluminium Extrusions
Aluminium Extrusions
Capalex Aluminium Extrusions

Powder Coating

Powder coating is a very durable method of providing a decorative finish to metals and a range of other materials.

Common Market Sectors

Common market sectors include, Window systems, Conservatory sections, hinges, lighting systems, curtain track and rail, desking systems including office furniture.


Our powder coating facility offers finishing in a variety of colours with RAL, BS or colour matched powders. We are able to powder coat both aluminium and steel components.

Powder coating offers many advantages over other finishes including;

  • A wide range of finishes and colours including metallic, glossy, clear and textured.
    • A newer and innovative finish, to resemble an anodised finish is now available, please ask for a sample. As well as being cheaper then anodising, it can produce a more consistent finish and we have a faster turnaround time with this finish than anodised metal.
  • Corrosion resistance.
  • Powder coating can be applied to most metal components including steel, Zinc, brass and aluminium.
  • The durable finish provides a surface finish which is less prone to chipping, marking and scratching.
  • Powder coating can be applied to components used internally and externally.

Andoised Powder effect, replace anodised products with a similar effect powder coating

Anodised Powder effect on the left, plain aluminium sample on the right. Note the amorphous smooth finish of the powdered sample.

List of RAL colour matched powders

Powder Coating Aluminium – The Process

The powder coating process starts with the metal components being cleaned, which helps the coating to adhere to the metal. This process is carried out in a multistage immersion water tank system as follows;

  • A de-greaser and light etch is used to clean the metal after which a two bath rinse cleans it down.
  • Next a non chromate bonder is applied to help the powder adhere to the aluminium.
  • Finally a drying oven is used to ensure no moisture is present when the items are powder coated.

The components are then suspended from a jig and passed through a spray booth where the powder is applied by spray guns. Once the powder has been applied it is passed through a curing oven where the particles melt and fuse together and adhere to the components surface. This produces a uniform, smooth, durable finish.

Capalex use a automatic continuous chain/conveyor system. Metal is loaded onto the hangars and then passed through the spray guns / curing ovens/coolers. This has a maximum length of 6000mm.

We also have the ability to do small runs and prototypes with a small secondary booth, with a maximum length of 2000mm. Although we primarily coat aluminium extrusions, we can coat small aluminium components, steel brackets, steel components and larger steel items.

Powder Coating Colours

The list of powder coating colours is vast. Generally we cover all the standard RAL colours. RAL is a colour reference system that was invented in 1927 by Reichsausschuss fur Lieferbedingungen in Germany. While there is a wide choice of standard colours we can also colour match any current corporate colours and produce custom powders.

For further information on powder coating colours please contact us.

Surface Finish

The main finish reflects the gloss level of the final product, usually being Gloss, Satin or Matt. There is also the choice between Flat finish and Metallic.
When choosing metallic powders Capalex always use the more expensive bonded powders as this gives a more uniform spread of metallic particles on the end product. If your product requires a metallic finish always ask if the powder is bonded or not.

Also there are more uncommon finishes like Hammerite, Textured etc.

Powder Types & Application Table

The powders most commonly used in the Powder Coating Industry are epoxy, polyesters, nylon, PVC, and to a lesser extent polyurethane and acrylic. There is also a Hybrid, an epoxy/polyester mix that is also often used.

We at Capalex use mainly epoxy, polyester and epoxy/polyester. These three types of powder cover most of our customer’s application requirements.


Polyester powders are far more durable for external work and this along with its many other good properties are usually specified by our customers for internal work as well.
Normal powder coverage of 50-80 microns.


Epoxy powders would not be recommended for external use but these powders have very good properties for internal applications.
Normal powder coverage of 50-150 microns.

Epoxy/Polyester (also known as Hybrid)
Epoxy/Polyester powders are a combination of the above powders and again would not be recommended for external work.
Normal powder coverage of 50-70 microns.

Novel Finishes

All novel finishes i.e. Metallic, textured etc. are either Epoxy or Epoxy/Polyester powders 
Powder Comparison chart

á Type of Powder
Property Standard Polyester Enhancedáá Polyester Epoxy Hybrid Polyurethane
Exterior Durability Good Excellent Very Poor Poor Good
Corrosion Resistance Good Good Excellent Good Good
Impact Resistance Excellent Poor Excellent Excellent Good
Flexibility Excellent Good Excellent Excellent Good
Adhesion Excellent Excellent Excellent Excellent Excellent
Cost Medium Medium / High Medium Low Medium
Film Appearance (50Ám thickness) Good Very Good Good Good Excellent
Chemical Resistance Good Good Excellent Very Good Good
Gloss Range 10-95% 20-95% 5-90% 5-90% 5-95%
Heat Resistance Very Good Good Poor Good Very Good
Abrasion Good Good Very Good Good Good

The choice usually comes down to using the product indoors or outdoors.
Indoors is usually Epoxy/Polyester and Outdoors is usually Polyester.

All powders that we use are TGIC free (Triglycidyl Isocyanurate) and are all in keeping with current personal Health and Safety and Environmental legislation. 

Gun Types


Uses electricity to produce a high voltage charge and produces a negatively charged particle of powder by adding electrons. This is the main type used in the industry and the type Capalex employ.


This blows the powder quickly through nylon tubes to charge up the powder particles and produces the opposite charge to the above guns by stripping away the electrons. This is very like rubbing a balloon on your jumper until it sticks by static electricity. A lot less common and is used mainly in specialist areas only.


Powder Coating Aluminium Office Desking system
Aluminium Powder Coating Booth, coating curtain track
Powder Coating Aluminium Extrusions, disability chairs