This is another weathering project where I used a tool for the first time.
The project started with an Athearn HO scale Hi-Cube boxcar. After painting the truck frames and wheel faces I sprayed the body with a flat finish. I then applied some Tamiya masking tape over the car initials and numbers. This tape comes in several sizes that are the right sizes for various HO scale car numbers and initials.
The next step was to weather the roof with rust spots. For an applicator I used, for the first time, a piece of an aquarium fish tank sponge filter. The filter came through Amazon and measured 13" x 5" x 1.5". This will produce a lot of applicators.
The technique I used was to paint just a little rust color on the applicator with a brush, being careful not to completely cover the surface of the applicator. I then tested the rust pattern on some white paper. When I was satisfied that there was just the right amount of paint on the applicator I hit the roof randomly, repeating when I needed more "rust".
I painted additional rust along the center of the car roof with a brush and sprinkled on some rust colored weathering powders. The sides of the car were treated with just the applicator. I finished the weathering with several shades of weathering powders applied with a makeup brush.
I am satisfied that the sponge filter applicator is good tool for rendering rust spots and probably will use it many more times. The rust spots could have been streaked if I had immediately gone over them by dragging a brush in a downward motion but I chose not to do that this first time. Maybe next time.