After your steel constructions are fabricated, you will need to decide how to protect them from corrosion. There are many ways to do this, and two of the most common are powder coating and wet paint spraying. Both these methods will protect the steel, and to some degree they can be used interchangeably.
For most people, the real differences between these two methods can be seen in the process, and not necessarily in the finished product. If you know what to look for, you will see that powder coating is probably a better method for your parts, and that wet paint spraying should only be used when necessary.
The advantages that powder coating offers are manifold. There really aren't a lot of advantages that wet sprayed paint has over powder coating, and the environmental problems that paint creates are a real concern. Paint is also a huge source of waste. As we all know, when we waste material, we waste money.
Why Use Powder Coating?
Powder coating uses an electrostatic charge to adhere powder to your steel parts. The powder is then baked on, and a very hard, durable finish is the result. Many colours of powder are available, and you are only limited by oven size when it comes to what can be finished with powder coating.
Because the powder is an inert material, there is very little waste in the powder coating process. When the powder is sprayed on to the steel parts, the electric charge makes sure that the rate of adherence is high. The over spray can be collected and isn't wasted. This creates a process wherein there is near zero waste.
When wet paint is sprayed, the vast majority of the liquid is either wasted or evaporates. This means that you are paying for a lot of material that will simply float away. The solvent in the paint that evaporates is a pollutant. When we take into account the advantages of powder coating, it would seem like wet paint spraying is at a rather severe disadvantage. The rate of waste with wet sprayed paint is well in excess of 50%, and may be much higher depending on how you measure it.
Powder Coating Covers Your Needs
In addition to being a more efficient process, powder coating offers you better protection for your fabricated steel parts. Because powder coating uses a very small particle to cover your constructions, it can accommodate mild stressing without breaking or cracking.
On average a powder coating will be about twice the thickness of paint, and also stronger. This will really come in handy if your steel constructions are going to be used by people, for example in a bike park. We have found that people are not always as gentile with civil constructions as we want them to be, so giving the constructions an extra strong powder coating is a good idea.
Quick & Controlled
When powder coating is applied to your construction, the entire process takes place under controlled conditions. From the media blasting to prep the construction for powder application, and every step along the way, a powder coating facility is more like a laboratory than anything else. After the final baking, your steel construction will be ready to be used within half an hour if you use powder coating.
When wet paint is applied to a construction it can take days to cure. During this time flaws can develop in the paint, and under certain circumstances the cure can even be affected. This will mean a substandard level of protection and possible problems with the strength of the paint. Powder coating has none of these issues, making it a far superior process.
The Problems With Powder?
Overall, powder coating is a better coating technology for most applications.
One of the drawbacks that powder coating has is that touch-ups can be problematic. If your powder coat develops chips from impacts or gaps from friction, you will have to use special paints to reseal the steel. Because powder coating is very hard, prepping the construction will take extra time, and it is best to use a professional who has experience with repairing powder coat finishes.
In addition to its repair, the colours that powder coating offers are more limited that paint. If you want your constructions to have a flashy metallic paint, you simply won't be able to use powder coating to finish them. We do mostly civil and commercial steel fabrication, so for the majority of our customers this isn't a concern. However, we will do a paint coat for you if your colour isn’t available in powder.
There are powder coatings that can colour match most design schemes. The durability and streamlined process that powder coating offers is an advantage in most cases, and we feel that the limited colour selection isn't an issue for most clients.
If you have any additional questions about using powder coating for your next steel fabrication job, we are here to help. At GLW Engineering we have more than 20 years of experience with steel constructions and can help you get the most out of your budget.
Be sure to contact us early in your design process, and let us give you the benefit of our expertise. We have a team of engineers and fabricators at the ready, and can offer you professionalism and excellent quality. You can find out more about shot blasting and powder coating in our Guide To Shot Blasting & Powder Coating. In this free resource we cover topics such as design, galvanisation, logistics and coatings. Click here to download your copy.
