Anodic oxide finish or dry powder: which is the better aluminium surface coating? Today, we’re going to break down the difference between anodising and powder coating bit by bit, so you can decide which aluminium finish is best for your needs.
Anodising aluminium involves an electrochemical process that gives the aluminium surface into a beautiful, durable and corrosion-resistant anodic oxide finish.
The anodising aluminium process begins with the aluminium dipped into an acid electrolyte bath combined with an electric current through a cathode. A durable anodic oxide layer will form on the aluminium surface during this procedure. This will cause oxygen ions within the aluminium to release, which then merge with the aluminium atoms on the surface, leading to an anodic oxide finish. The result? A porous aluminium surface, which can then be coloured with dyes and sealed afterwards.
Painting directly onto anodised aluminium is not recommended as the surface doesn’t provide a good hold for the paint. However, you can use an etching primer coat and then sand this smooth before starting to paint.
Because the colouring occurs via a treatment to the metal, you’ll find it takes on the aluminium’s natural corrosion-resistant properties. As a result, you can expect less damage to this coating due to wear and tear. It’s the ideal process for aluminium that will be used in hard-labour industries, like agriculture, where there’s a high chance of chipping a powder coating. However, this method typically has a lower level of chemical resistance.
With a permanent bond between the coating and the metal, you can expect your anodised aluminium to keep its colour for years to come, no matter the colour.
Because the aluminium is submerged into the bath and allowed to drip before curing, it creates an amazingly even and consistent finish. So, you won’t have to fret over missing the nooks or crannies or getting uneven coverage when it comes to anodised aluminium.
The electrolyte bath used in anodising can be used many times, making it environmentally sustainable compared to other options. It also does not use VOCs (volatile organic compounds) and no hazardous waste is released into the atmosphere.
As the name suggests, powder coating is a completely dry paint that contains no solvents. Furthermore, as the powder coating does not have any liquid, thicker coats of paint can be applied without running.
The powder coating aluminium process is relatively straightforward. First, the powder is applied to the aluminium using an electrostatic paint gun, giving the powder a positive charge. This positive charge enables the paint to bond firmly to the metal’s surface. Then, the metal is placed inside an infrared oven, where the powder melts into a consistent film. Lastly, a cooling process seals and hardens the paint. The final product is a tough and durable powder coat finish that resists scratches, chipping and peeling.
Like anodised aluminium, you can’t just directly paint onto powder coated aluminium. You need to prepare the surface first. To do so, lightly sand where you want to paint. This will provide some grip for the paint without it becoming uneven.
Powder coating can be used on more than just aluminium; it works on any metal that can tolerate the curing temperatures, including most metals used in construction. It’s a perfect coating for metals that are not aluminium too. It’s also highly versatile, working well on non-metal objects with a metallic surface treatment, as long as it can be grounded and withstand the curing temperatures during the finishing processes.
The powder coating covers imperfections in the metal, such as grind or weld marks. It also avoids colour variation, as the powder colour is always constant.
While anodising is generally considered affordable, it can be expensive for some applications. This is where powder coating is favoured; its large-scale coverage makes it one of the most affordable and durable methods.
Both anodising and powder-coating methods offer unique advantages. The proper choice depends entirely on your application.
Looking for powder coating or aluminium anodising in Melbourne? At Lightning Laser, we offer premium-quality services and metals using both methods. With vast expertise and a proven track record, we can confidently say we provide the best powder-coating and anodising in Melbourne. So call us now for a flawless aluminium coating job!