The Powder Coating Process
Okay, but what is Powder Coating?
This was interesting to me too! Why are we so gung ho about powder coating? Well, there’s a better article for that here.
This article is going to be less about the why and more about the how of powder coat. I hopped on the phone with our pal Andrew at Columbus Powder Coat (our go-to vendor for all of our powder coating needs) and asked him to detail the process for me.
Receiving and cleaning
The first part of the process is getting the item to the powder coat company. After receiving the item it goes directly to the sandblasting area. Sandblasting not only removes all of the oil and grit on the piece but also opens the microscopic pores in the metal itself. This process allows the powder coat (when it is applied) to bond to the metal during the curing process. Time in the sandblasting area is dependent on a few factors, but railings usually take about thirty minutes. “During this process, the piece turns almost white, we call it a white-wash, this means the sandblasting process is complete.”
After sandblasting, the piece moves into the shop where the sand gets cleaned off, and the piece is hand-sanded to ensure all grit and particulate is removed. It is then cleaned a third time, but mostly dusted off and blasted with compressed air to ensure all of the fine sanding dust has been removed from the piece. The piece is never rinsed with water or cleaning products. As Andrew put it: “remember the pores in the metal I was talking about? Those need to be dry, and clear of any particulate, cleaning product would get into those pores.”
Priming
This step is not always necessary. Typically we only request a Zinc primer when the finished piece will be outdoors or in a harsh environment. If a Zinc primer is needed, it is applied as a base coat.
After cleaning, a thin layer of Zinc primer powder is applied and it goes into the oven for a partial cure. A partial cure goes in at the same temperature as a top coat (400 degrees) but for less time. “The Zinc primer is applied in a layer between 1.5mm and 3mm thick. The thinner the better, at a partial cure (between 15-20 minutes). This allows the powder to turn into a gel.”
After the partial cure, the piece is removed from the oven and allowed to cool.
Top Coat/ Finishing Coat
The piece is then ready to move to the final step in the process, the fun part: color! The folks at Columbus Powder Coat then change the color for the oven and apply the desired color (typically our clients like the flat Tuscan Black). The powder coat is applied, and placed back in the oven, this time for a full cure. Baked again at 400 degrees for 40- 50 minutes. The first 10-15 is for preheating the metal, and the last leg allows the powder to gel, and adhere to either the metal or the base coat.
Finishing Up
After baking the topcoat, the piece is allowed to cool, and then it’s ready for pickup. Typically we will call you when we know a piece is going into the powder coating process and schedule your installation. This way, we can pick the piece up directly from the powder coater, and take it directly to you. This ensures it is not scuffed or damaged before it arrives at your doorstep.
Honorable Mentions
A big thank you to our guy Andrew at Columbus Powder Coat. I gave him a quick call as I was writing this article and he helped walk me through their process. All information in this article came directly from him. If you’d like to know more about them head over to their about us page.
