Try red, yellow and orange. Mix them systematically up until you come up with the correct rust shade you want
What Colors Do You Mix To Get The Color Rust?
I would use orange, brown, a dab of yellow, a dab of black, and a dab of gold.
I would also try more yellow and orange with maybe a little red. A site with other color mixtures go to, Kids Craft Zone.
The site list how to get browns, purple, black by mixing colors. Just a thought.
The site list how to get browns, purple, black by mixing colors. Just a thought.