We're done creating the metal texture. Now we'll create a rust texture. Create a new layer (Layer> New> Layer) and name this new layer "Rust".

Open the Fill tool (Edit> Fill or Ctrl+F5). Select "Color" from the drop down menu and choose an dark orange color. I used the color #7f4000 but you can use any color that you wish. This color will appear as the rust color. When done, click OK and OK again.

Now we'll add a sandy texture to the layer. To do this, open the Filter> Texture menu and select Texturizer. In the texturizer window, adjust the setting to achieve the look of rust that you like.

Now we have a rust and metal texture. The next step is to mask out portions of the rust. Begin by adding a layer mask (Layer> Add Layer Mask> Reveal All) to the "Rust" layer.
