The bottom of a grill can rust out for a variety of reasons. One of the most common reasons is due to exposure to the elements, such as rain and snow. These elements can cause the metal to corrode and rust over time. Additionally, the accumulation of grease and food particles on the grill can also contribute to rust formation.

Another reason for grill rust may be due to the quality of the metal itself. Some grills are made from lower quality metal that is more prone to rusting, while others are made from higher quality metal that is more resistant to rusting.

There are also a few other factors that can contribute to grill rust, such as the type of fuel used, the location of the grill, and the overall maintenance of the grill. For example, grills that use propane or natural gas tend to rust less than those that use charcoal, due to the lack of moisture in the fuel. Grills that are located in damp or humid environments are also more prone to rusting.

To prevent grill rust, it is important to regularly clean and maintain the grill. This includes removing any excess grease and food particles, as well as applying a protective coating such as a grill cover or paint. It is also important to store the grill in a dry location when not in use.

In summary, grill rust can occur due to a variety of factors, including exposure to the elements, the quality of the metal, and the type of fuel used. Proper maintenance and storage can help prevent rust from forming on the bottom of a grill.