Our Provence Outdoor Collection features iron frames that are powder-coated at 90 parts per million. We found this to be the sweet spot to keep the finish as close to raw iron as possible while still keeping it protected. Any thicker and it was subject to \"orange peeling\" or flaking off through the years. At this time, we do not recommend any additional finish. It's important to note that over time, they may develop a natural patina or rust, typically around 15 years. Our goal is to bring back the qualities we love about vintage furniture, and we believe in letting the material's natural state speak for itself.