Powder coating is a type of coating primarily used to cover aluminium and steel products that is applied as a free-flowing, dry powder.
The main difference between a conventional liquid/spray paint and powder coating is that the powder coating doesn’t need a solvent to keep the binder and filler parts in a liquid form. The coating is applied electrostatically and is then cured under heat to form a strong, long lasting “skin”.
Powder Coating, when performed correctly, produces a harder, tougher skin than conventional painting methods. This toughness makes powder coating extremely popular, and somewhat essential, for aluminium or steel items that are exposed to conditions such as weather and general wear and tear.
Our premises are fully equipped to perform the entire powder coating procedure from prep through to curing.
The Pre-Treatment Process
Preparation is a vital ingredient in producing professional, lasting results in powder coating. We use a Chromate Conversion pre-treatment system as we find it to be the most effective preparation treatment process available. When chromate conversion coating is applied, its purpose is to passivate metal substrate, preventing oxygen in air to corrode the metal surface.
Our pre treatment process is based on the following steps:
1. Acid bath to clean the product and provide an etch for Chromate.
2. Clean water rinse.
3. Chromate conversion to passivate the metal
(the process of making the material passive in relation to powder before combining both materials together).
The chromate protects the surface from corrosion and is done prior to powder coating.
4. Final clean water rinse.
The product is then dried ready for powder coating.
The Application Process
The powder coating is applied to objects by spraying the powder using an electrostatic gun. The gun imparts a positive electric charge to the powder, which is then sprayed on the item compressed air spraying and then accelerated toward the workpiece by the powerful electrostatic charge.
Our application process is as follows:
1. Powder coating is applied using specialised Electrostatic Equipment.
2. Powder coating is used to provide a durable and hard finish that is tougher than wet paint.
3. It is applied as a free flowing and dry powder and is then ready for curing in our oven.
4. Powder coating comes in a large range of colours and is used for a diverse range of products including pool fencing, balustrade furniture, pergolas, windows, doors and extrusions.
The Curing Process
The curing process is essential in setting the powder coat. It requires a high temperature for a certain length of time, depending on the material’s characteristics in order to fully cure.
Our oven curing process is as follows:
1. After powder is applied the product is ready to be oven cured.
2. Our gas oven is fired up to 200 degrees Centigrade.
3. When a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called cross linking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties for which the material was designed. Depending on the product coated, the powders cure at 200°C for 8 to 10 minutes.
Whilst we don’t perform sand blasting on-site, we have relationships with reputable sand blasters in the area. Sand blasting is often required as part of the preparation process for powder coating so we ensure that our service covers everyone’s needs by having reliable sandblasting partners available.