How to Create a Rusty-Looking Car for an Underwater Halloween Display

Let me tell you, Google wasn’t much help when I searched for “how to make my car look rusty and underwater.” All I could find were endless tips on how to remove rust from a car (not exactly what I was going for!). Finally, I struck gold in a mom’s group where a clever mom shared a recipe for washable window paint for her toddler. I don’t remember the website, but credit goes to that brilliant mom! What do you know—it worked perfectly on my car!

I have created another instructable on how to make a Kraken :-)

It's here: https://www.instructables.com/Halloween-Underwater-Theme-How-to-Make-a-Kraken/

A Car – Got a spare car lying around? Perfect! (Or use any car you’re willing to make temporarily spooky.)

Washable Paints – Tempera or poster paints work best in shades of brown, dark green, and light green.

Eco-Friendly Dishwashing Liquid – Helps the paint foam up and wash away easily, without harming your garden if it runs off.

Water – For diluting the paint and for the final cleanup.

Spray Bottle – Any recycled spray bottle will do (repurpose one from an old cleaning product).

Sponge – For adding those final rusty, grimy details.

Bucket of Water – For initial cleanup after Halloween.

Blue and Green LED Lights – To create a ghostly underwater glow around the car at night.

Skeleton Prop – For that extra creepy touch in the driver’s seat.

Time to give your car that ocean-ravaged, rusted look!

Mix Your “Rust Potion”:

1. In your spray bottle, combine 1 cup of paint with ½ cup of dishwashing liquid.
2. Add water to make the mixture more watery but not too runny (you want it to stick but drip just a little).
3. Shake it up well to get an even mix.

Spray the Car:

1. Start with brown paint and spray spots all over the car’s surface. Don’t cover the entire car—"paint by spots" to make it look more natural and weathered.
2. Next, switch to dark green and add more splashes around the car, layering it over the brown in spots for a mossy, algae-covered look.
3. Finish with lighter green, spraying it in patches for a final touch.
4. Repeat the process, layering the colors in random, spotty patches until you’re happy with the effect. The runny paint will naturally create streaks, giving it an organic, underwater rust look!

Add Rust Details with a Sponge:

1. Once the spray paint is dry, dip a sponge in brown paint and dab it around the car, adding heavier patches of “rust” here and there.
2. Let the sponge marks dry and watch as your car transforms into a rusty sea treasure!

Nighttime Spook Factor:

1. Place blue and green LED lights inside the car and around its exterior to give it an eerie underwater glow.
2. Clean the driver’s window and place a skeleton in the driver’s seat for that chilling, final touch!

Cleanup Time (After Halloween):

1. To remove the paint, start with a bucket of water and rinse off the excess paint. The dishwashing liquid in the mixture will make it foam up, which makes it easy to remove.
2. Once most of the paint is off, spray the car down with water to get it squeaky clean. The paint should wash away easily, and the foam minimizes color runoff onto the ground.