Powder coating is a great way to produce a clean, perfect finish on any metal project. It creates a protective barrier between the metal and the elements, reducing the risk of corrosion, rust, weathering, or other damage. But, ensuring that the metal surface is in good condition is essential to the final product. Before you drop off that metal project, here's a look at what you need to know about preparing it for a powder coating application.
One of the biggest problems for powder coat finishes is oxidation on the metal surface. When the metal has any oxidation or oil on the surface, it can actually come between the powder coat and the metal, preventing that powder coat from adhering to the metal correctly.
In fact, poorly prepared metal may even end up with holes in the powder coat. Those holes will leave metal exposed, which could eventually corrode and cause the powder coat to flake. Preparing the metal eliminates the corrosion and the oils that may be on the metal surface. This leaves behind just the bare metal, so it's easier for the powder coat to adhere.
The Alkaline Cleaning Process
Cleaning the metal with an alkaline cleaner will strip all of the oil and other residue from the surface of the metal. Dip a clean, soft rag into an alkaline cleaner and wipe all of the metal. If there's any discoloration left behind from the cleaner, dip the whole thing into a tub full of a solution of diluted nitric acid. If you'd rather, you can achieve the same cleaning with a phosphoric acid cleaner. It will clean the surface of the metal without the residue that alkaline cleaner leaves behind.
Oxidation Prevention Steps
Once the metal surface is clean, you need to treat it to prevent oxidation. Rinse the surface with water then wipe it dry with a soft cloth. Once it's dry, treat it with an oxidation inhibitor. You can choose from several types for this – either chromium phosphate or chromate. Make sure you read the application instructions closely, though most require just a thin coat to be effective.
The steps here will help you with the metal preparation process before powder coating. If you want help with the chemical application, ask your powder coat specialist, one like Tri-State Fabricators, for guidance. He or she may have a metal preparation specialist to work with, or could provide some recommendations for you to make sure that your metal is ready for treatment when you drop it off.