Spray paint a car? That sounds like it could get you into a lot of trouble.
But use a stencil with spray chalk, and you’ll find you can create neat, bright markings that last for a couple of months and that gradually weather away.
Spray chalk is used on non-porous surfaces for temporary marking. As such, it works great on glass and shiny metal and shiny plastic. Think cars, whiteboards, refrigerators, windows, mirrors, slick vinyl coverings, polished rock, anything laminated. With a little commitment to cleanup, it can also be used on pavement, smooth concrete and some other building materials.
With spray chalk, the easiest thing to do is a light colored stencil on a dark surface, or a dark-colored stencil on a light surface. We’ve done black on a variety of bright surfaces, and white on a variety of dark surfaces with great effect. Spray chalks are also available in a few bright colors, but these are used primarily for marking streets and building sites. (The color selection for spray chalk currently isn’t great.)
Step by step
Find your image
Pick an image that doesn’t have too much detail. A single face works great. If you have two or more faces to stencil, maybe break them up into different stencils. Combining a face or an image with a text stencil usually helps people to understand what your stencil is meant to convey. (Such as, ‘Welcome to Bulgaria!’)
Prep your image
Crop your images close, and then replace the background with either black or white depending on whether the surface of your car is a bright or a dark color. The background of the image should match the surface you want to paint on: if the surface is dark, replace the background with black. If the surface is light, replace the background with white.
Stencilize your image
Upload your image to Bay Stencil, and then when you get the first email back, just choose to ‘get the halftones’. (You don’t need to look at all the cool stencil separations, because those are for multi-color, multi-layer stencils, and what you want is a single halftone stencil.)
Cut the stencil
You can cut the stencil on a laser cutter, or a craft cutter. The cuts are super detailed, so I don’t recommend hand-cutting these. Any cutter that accepts an SVG as input will work. If you are having trouble with cutting the details in the halftones, download a version of the halftone with fewer lines and it should be easier. With a craft cutter like a Cricut, 80 lines is about the best you can do. (It’s also the resolution for the example shown here.) With a laser cutter or a larger format vinyl cutter, you can go up to 200 lines side-to-side, but with a table top craft cutter 60 lines may work better for you.
Paint the stencil
With the stencil in hand, you’re going to want some stencil adhesive (or any other repositionable adhesive) to stick the stencil to the surface of the car. Make sure there aren’t a lot of gaps or irregularities; the stencil should lay flat and flush against the surface. Paint as you would any stencil, being careful not to underspray. Let the chalk dry for just a few seconds, and then peel the stencil off the surface, being careful that it doesn’t scoot around. When the stencil moves around, it can smear the chalk underneath, and you don’t want that.
Beware using spray chalk on plastic or porous surfaces
Side mirrors are often made of porous black plastic that really keeps the color of the spray chalk. Some bumpers (especially older ones), windshield wipers, window bushings, some trim. Those plastic fins in the grill (yes, plastic even on a luxury car). Stay away from anything that isn’t smooth, shiny, painted metal or glass.
Let people know that it’s spray chalk
Before you consider playing a prank: most people have never seen spray chalk (although, if you ask them what they think football and soccer fields are painted with, I’ll bet they come up with the right answer). So, you don’t want to go to the hospital. Bring along a rag so that you can quickly demonstrate that the spray chalk comes right off those shiny metal painted surfaces.