It’s no secret that powder coating is one of the most durable coatings on the market and can withstand extreme environments. Powder coating does have its limits and there are some best practices. We often get asked about the materials and surface conditions that powder coating can be applied over. We decided to clear up some misconceptions about powder coating over rust.
Rusty metal is difficult to clean and usually won’t accept traditional paint. Because powder coating is applied using a static charge you MIGHT be able to get powder to stick and cure over powder, but that doesn’t mean you will get a lasting finish. First of all powder coating (like most other coatings) needs a clean surface to cure over. If you do get the powder to adhere to a rusty surface the powder may get bubbles, out gassing, or imperfections in the surface that could cause a poor finish.
Another reason we don’t suggest applying powder coat over a rusty surface is because the rust tends to grow over time and can flake off. Your powder coated finish is only as good as the surface you lay it over and that flaky rust could fall off taking the powder with it. There is a lot of time invested in preparing and powder coating a project so we don’t suggest just laying powder over rust metal.
So that’s our take on the rusty metal topic for powder coating. The best practice is to remove all prior coatings or corrosion off of a project before you fill you powder gun. If you don’t have the option to media blast your parts you can also use Eastwood Rust Dissolver to clean and remove old rust off the part. This leaves an extra step of cleaning but works well for those without a media blaster. Find all of our powder coating guns, colors, and supplies HERE.