How Do You Powder Coat Wood?

Most folks coming into contact with GCC Coatings for the first time say: “I didn’t even know it was possible to powder coat wood.” It’s hard to keep track of how many times one hears that phrase over the course of a week. It is actually a natural response though because applying a powder coat to wood is a technology still in its infancy.

The earliest days of powder coated wood were quite difficult. Heating the substrate prior to spraying the powder is a key step in getting the finish to actually stick. It’s a pretty well-known fact that wood doesn’t do all that well when introduced to intense heat. Wood is also a notoriously awful conductor and it can be really hard to get a part to heat uniformly.

Before researchers finally got the process right, increasing the temperature of the heat sensitive wood caused it to crack and warp. In addition, wood fibers would appear raised on the surface of the board. Parts that were shaped or routed faired far worse with most having a finish that was uneven and not quite cured.

Since emerging from that research stage and going mainstream, however, spraying powder on wood has quickly gained in popularity. More and more manufacturers are looking for an option that is all-around better than conventional liquid paint. Consumer demands and expectations are also fueling an increased interest in powder coating.

The Process

So basically, the same process used for applying a powder coat to metal could not be used to apply powder to wood. Developers had to practically start over in order to come up with a proper method for preheating, the ideal conditions for the preheating environment, a system that could apply uniform thickness, and wood material that could hold up under the pressure.

It all starts with the right piece of wood. Researchers discovered that medium density fiberboard (MDF) is the best wood for powder coating. MDF is an engineered wood product made by mixing and compressing wood particles, resins, and adhesives together. Its homogeneous surface and low porosity make it perfect for what we’re trying to do.

We have very specific criteria that a MDF board must meet before it can be used. A board must have internal bond strength of at least 130 pounds per square inch (PSI) in order to withstand the heating and cooling portions of the process. It is also necessary for the MDF board to have five to seven percent moisture content so that the surface of the board becomes conductive when the powder is sprayed.

Through our parent company, Greenberg Casework Company Inc., we are able to manufacture many of the parts our clients want to have powder coated. So the next step in our process is to actually make those parts. We are able to make and powder coat parts of varying shapes, sizes, and configurations. We use precision CNC routers with custom and off the shelf tooling which makes it fairly easy to do multiple operations in a single pass. We use an automated edge sander to ensure the powder finish will be consistent on the corners, edges, and both sides of the wood.

Next, the manufactured parts will need to be cleaned up. We have to remove any and all debris and surface liquids prior to spraying in order to ensure an even and consistent flow as well as to ensure the powder will actually stick to the MDF. Once clean, the parts are ready to move into the latter part of the process where they will be heated, powder coated, and cured.

First, we’ll hang the parts on a moving conveyor. The conveyor is the vehicle that will move the MDF parts through the preheat oven, the powder coating booth, and finally through the gel/cure oven.

The first stop for the MDF is the preheat oven. There are actually three types of ovens that can be used when powder coating wood: an infrared (IR) catalytic oven, a convection oven, or an ultra-violet (UV) oven. Both the preheat and gel ovens that we use are IR catalytic. Unlike convection, infrared catalytic ovens can heat the wood surface without compromising the integrity of the board.

There are several reasons we preheat the board. Probably the most important reason for heating the MDF before applying the powder is to get that five to seven percent moisture content in the board to render the surface conductive. Why we do this will make sense once the next part of the process is explained.

The next stop on the line is to the powder coating booth. Automatic sprayers are used to ensure consistency of application. At the tip of the spray gun the powder particles receive an electrostatic charge. The charged particles are then more readily attracted to the grounded surface of the MDF part. This is why both having the moisture content in the board and the preheating process are important. Without either of those elements, the powder would have a difficult time sticking to the board.

Once the parts move out of the powder coating booth they enter the gel oven. Here the powder will gel, flow, and permanently bond to the surface of the MDF board.

Finally, the boards are ready for curing. The end result is a MDF part with a finish that is able to withstand scratching, cracking, and other surface abrasions. Once cooled and cured the part will have a strong, durable powder coated outer shell. After curing, the parts are packaged up and shipped out to the client.

From beginning to end that is the process we are using to powder coat wood. GCC Coatings has been offering its wood powder coating services for several years now. We have worked tirelessly to improve and perfect our particular process. And we will continue to invest time and resources to ensure that we remain on the cutting edge of powder coated wood technology.

GCC Coatings is capable of completing and fulfilling both large and small orders. Whether you have a custom, one time job or consistently need the same parts we can provide both manufacturing and powder coating services to you.

If you’re interested in looking into the possibility of using powder coating for your next project feel free to give us a call today to get a quote for your next job: (815) 624-2332. For free samples, please visit this page and fill out the form.