The painting process is a crucial stage of towbar production because it enhances the durability and robust nature of the towbar. The layer of paint protects the metal towbar from the elements, making it less liable to rust, so covering the towbar effectively with paint makes a huge difference to the durability and lifespan of the towbar.
Historically, we have used powder coat paint to finish and protect our towbars and this has proven to be an effective method. However, we have recently started to use an E-coating method which is widely used by Original Equipment Manufacturers (OEMs), so this is the paint we will be using in future towbar production. In this article we will cover:
- What is powder coat paint?
- Why were we using powder coat paint?
- Are there any problems with powder coat paint?
- Why did we stop using powder coat paint?
- What type of paint do we use now?
- How is this better than powder coat paint?
- Does the new paint have any benefits to the fitter or the end-user?
What is powder coat paint?
Powder coat paint is a process of applying a dry, coloured powder to a towbar, usually by using an electrostatic powder gun. The gun takes the powder, puts an electro-static charge through it and takes it to a raw metal part. It then has a finish on it that needs to be put through an industrial oven which applies heat. The powder then flows into a liquid and as it cools, it creates the aesthetic you see on most industrial finishes.
Powder coat paint is a widely used method that involves building up the powder layer to give the correct thickness of paint once it flows into a liquid.
Why were we using powder coat paint?
Powder coat paint has been the industry standard for many years and it is extremely hardwearing. It has excellent corrosion resistance when it comes to sealing a metal part from the elements and is used for a variety of different applications. We also use powder coat paint because it is more environmentally friendly than wet paint. Powder coat paint still meets industry standards and is widely used across many of our products due to its durable and robust nature.
Are there any problems with using powder coat paint?
While there is nothing technically wrong with using powder coat paint, there are some limitations. Powder coat paint has an optimum thickness, determined by the number of microns which is usually 80-120 microns for 1 layer of paint. So if something is going to come into contact with the towbar or move, the more layers of paint you have built up, the thicker the tolerance is. This is more common with detachable and retractable towbars because the paint can be quite thick. Additionally, an operator is usually required to manually apply the powder or a machine that can apply it in a more consistent manner.
Why did we stop using powder coat paint?
Although powder coating is a proven process that has been used for years within the industry of aftermarket towing, the OEM vehicle manufacturers have set a standard for OEM equipment that they are happy to put their brand logo against. The E-coating system meets these OEM standards. E-coating is a more consistent, reliable and controllable process that gives a higher corrosion resistance. This means that moving forwards, our aftermarket towbars will have an OEM grade of paint finish.
What type of paint do we use now?
We have recently started using E-coating across some of our newer products. E-coating is a 12-stage dipping process with a series of tanks filled with chemicals for rinsing and preparing the towbar. It involves hanging the towbar on a fly bar and using a transporter that moves along a series of tanks to prepare the part ready for painting.
The first half of the E-coating process involves cleaning the towbar to remove any impurities before it goes through a conditioner and a zinc-rich pre-treatment to ensure the longevity of the coating. The towbar is then submerged in a tank of liquid paint and a charge of electricity goes through the tank which builds up the layers of paint, based on how much electricity is put through it. The layers of paint that bind all over the towbar are built up, including hard to reach areas, and it ensures a consistent thickness all over.
Once the paint has been applied, it goes through two more stages to remove the outer coating of the applied paint before going through a series of ovens that exposes the towbar to heat and gives the finish on the towbar.
E-coating is a more consistent process, whether it's used for 50 or 50,000 parts.
How is this better than powder coat paint?
E-coating is around 15-20 microns thick which is a much thinner coating than powder coat paint. Upon application, the towbar is submerged and the whole part is exposed to the paint in one go and as the electric charge goes through the tanks, it builds up the layer of paint all over the part. This provides a consistent paint thickness all over the towbar so it is particularly good for materials that have threading for screws. The paint and chemicals used means it's not very labour intensive, making E-coating a more cost-effective process.
Powder coat paint can be subject to scratching or stone chipping if exposed to harsh environments. If it is scratched, part of the paint can chip away and water can get underneath it and potentially cause rust to the whole towbar. Whereas with E-coating, if it gets scratched, the only part of the metal exposed to potential rusting is the part that has been scratched.
In addition, when powder coating is applied, the faraday effect can occur, especially around corners. This means that powder paint is pushed naturally away from the corner so consistent coverage is not achieved. It's harder to get a uniform coating if there is a lot of complexity to a part.
What benefits does E-coating paint have to the fitter or the end-user?
E-coating meets the requirements of OEMs as an aftermarket product whilst still conforming to the industry standard salt spray test. The paint is baked into the towbar so it binds to the part which makes it less liable to chipping or peeling. This is beneficial to towbar fitters because there is less chance of damaging the paint upon fitting. It is also beneficial to the end-user as E-coating is less prone to stone chips, knocks, damages, and flaking off because of the way it has been applied.
While we are transitioning to use E-coating across our products over the next few years, we still use powder coating in the meantime on our existing products. Powder coating adheres to industry standards and has proved to be a hardwearing and effective method for many years.