The Benefits of Powder Coating Your Metal Fence

The first I heard of the term powder coating was about an in-store retail display. That is a common usage but I did not realize until years later that it is not simply a process to decorate retail displays being handled by customers. Powder coating is more often used on fences, railings, and gates to increase the lifespan of these products outdoors including extreme weather.

Powder coating is a process used to decorate, finish, or protect something, most commonly made of metal. On a basic level, it’s similar to paint but uses dry powder instead of adhesive liquid. This creates many different advantages which will be discussed later. The substance is applied to the part by using a gun which creates an electrostatic charge while spraying powder, making it adhere to the object that is meant to be coated. After this is complete, heat is applied to cure the powder making it permanently affixed to the metal.

The ingredients in the powder include pigment, a curing agent, leveling agents, flow modifiers, and additional additives. This polymer resin system is designed to bond for strong protection, becoming extremely hard and able to hold up against great force. This resin used for powder coating is extremely durable, so much so that cleaning with a heavy-duty method such as power washing will not damage the coating. Similar coatings are designed to mimic the look of another material, for instance, a metal fence may be powder coated to look like plastic. By adding pigment, you can create nearly any color imaginable.

There is a rather scientific explanation for how the process works. By using an electrostatic charge during the application, the powder particles are drawn to the component. This is usually done in a booth or clean room to prevent unwanted dirt from showing on the end result. The most common way to hold small pieces and larger items like fence posts are by hanging them on clean metal hooks. It is also important each item is handled with care after the coating has been applied because the powder can be accidentally knocked or brushed off before it is cured. As the powder connects to the component, the bonds grow stronger, but they are not solidified until heated. Much like with liquid paint, additional coatings can be applied to the same item increasing protection and longevity.

After the coating has been sprayed, the parts must be baked in a curing oven where the particles chemically react, becoming more resistant to breakage. Pay special attention to the instructions from your powder manufacturer to make sure you use the appropriate cure schedule or time and temperature. Under curing your parts will not allow adequate conditions for the polymer chains to bond, leaving the coat brittle and less durable. Over curing can lead to similar results. It is common for a powder to have some over bake stability in it. This is because powder may vary in thickness across your items. Your work has some safeguard by allowing for the thinner areas to bake as long as the thicker areas without burning. Understand that this rule applies to longer bake times but not to higher temperatures.

Before a powder coat, it is a good idea to clean and blast the parts. The first step, cleaning, can be done best with a power washer but there are plenty of amateur options as well. The main objective in this step is to remove any dirt, oil, grease, or contaminants. If your metal is brand new, using a soapy or clean rag may be all that you need to remove dust and dirt. If you don’t have access to a power washer, just get your hands on a strong brush and a solution designed for cleaning metal. Do your research here and make sure that you are not grabbing a cleaner that can corrode the parts or weaken the metal. Powder coating sticks best to clean metal, plus you’ll be less likely to have any dirt or specks in your finish if the parts are clean.

Once clean, blasting, most often done by sandblasting or media blasting is a process used to remove things like corrosion, rust, or existing paint which will help the powder coat adhere better. During the blasting process, not only are the unwanted elements removed but many tiny scratches are created on the metal leaving microscopic hills and valleys. Instead of having a completely smooth surface that the powder can slide or peel off of (called delamination), the part is left with a faint rough finish called a surface profile. This tiny texture actually creates a greater and uneven surface area that is perfect for the powder to securely attach to.

When you finally get to the powder coating stage, there are a few key things to keep in mind. Adjust your spray gun to a low setting, between 5-10 PSI. Try testing out different PSIs until you can form a nice cloud of powder. There is very little pressure needed to propel the particles and you’ll find that more intricate parts are coated easier with a slower spray. It helps start spraying at the most complex areas and making your way to the less detailed places. An LED light can be shined on your part to help you more easily identify areas that aren’t getting fully covered. Applying just the right amount of coating can take some practice. Too little coating can leave vacant areas where the bare metal can oxidize and rust faster because it is not protected. Too much powder, and you may wind up with a bumpy effect, referred to as orange peel. This can lead to chipping but also has a less appealing look than the desired smooth finish.

Make sure you protect your skin, eyes, and lungs by using protective gear whenever spraying powder. A respirator (or gas mask) can keep you from inhaling any particles. Goggles, a long sleeve shirt, and disposable gloves are also helpful to keep the powder off you.

In summary, a double or even single layer of powder coating on your metal fence can extend the life, save hours of cleaning and maintenance over years, and simply keep your property looking better with a fence or gate that masks the signs of aging. I hope you’ve enjoyed this article and good luck with your projects.