Disappointing, I don't know if it works on rust because it is an anti-rust product, but I passed it on the small fence about 5-6 times with this product. I had bought the brown color and it took one coat with it and two coats with the black one, maybe it needs a third coat because the black one hasn't covered it exactly. Luckily, I didn't use it on the other fences. Now, beyond that, I don't know what job it does as an anti-rust product.