Part of my scene is a guy getting boiled in the middle of the driveway. We have a cauldron to hold the skeleton; simple, cheap, plastic.
Enter the oatmeal.
All you need to rust and age up a cauldron is:
- spray paint
Glob it all over the cauldron in various points making a big mess of your hands, the floor, and a dog who thinks she wants to eat oatmeal sand glue.
Let that dry. It will look disgusting and weird, but it's okay. Now we bring out the paint. Black spray paint. I use the plastic adhering because it's what I had and to smooth over any color changes.
Orange is the best paint for it. I start at the bottom and spritz at a distance. It takes a few turns of the cauldron. I tried to mix some brown in, but then I ran out. So you can add spritzes of brown if you'd like to deepen the rust.
After that dried, I added flecks of the red. Not too much, it'll overpower if you don't stand way back and only twist with the wrist. If you go too far, you can always go over again with the black to bring her back.
Sigh, how long until labor day?