When it comes to Rust Bullet, the number of coats you need can vary depending on how much protection your surface needs. Generally speaking, for a light-duty application such as protecting bare metal or preventing rust in small areas, one coat should be sufficient. However, if you are looking to protect an area with heavy wear and tear or that is exposed to harsh elements like saltwater or extreme temperatures then two coats may be required. Additionally, any time you’re applying Rust Bullet over an existing layer of paint or primer we recommend at least three layers to ensure full coverage and maximum protection. Ultimately the goal is to achieve a uniform coating that bonds strongly with the substrate so take your time when applying multiple layers and make sure each coat has fully cured before adding another.