How To Use Spray Chalk For Your Next Guerrilla Ad Campaign
Spray chalk is an item you can typically buy in the art section of your local arts and crafts store or even some big-box stores as well. However, making your own spray chalk for a large ad campaign is very low-cost and easy to put together.
Using spray chalk is beneficial because it is a temporary advertisement that will usually turn out much brighter in contrast to regular hand-drawn chalk advertisements. This technique is common to use on college campuses and around public areas.
Before you start any guerrilla campaign such as this, make sure you check out your local law and regulations for advertising in public areas. Often times, local authorities might not know the legality of these types of ads so it’s good practice to have a local representative sign a document allowing this type of ad.
Making spray chalk is much easier than you think
Supplies:
Water
Tempera Paint (This is a water-soluble paint so it won’t leave permanent marks)
Cornstarch
Squirt bottle
I suggest using half the cornstarch to water ratio (e.g., 2 cups of water, 1 cup of cornstarch). However, I tend to add the cornstarch to hot/warm water slowly in order to work out all clumps and not to make the mixture so thick that the spray bottle clogs.
Once the mixture is free of clumps, add a small amount of any color you want. Usually a tablespoon of tempera paint per 3 cups of mixture is more than enough, but you can make the colors as deep or light as you want.
After adding color and making sure the liquid is clump-free, pour the mixture into a clean spray bottle and test outside. Apply a thin layer at first to test out the application level. The chalk should dry in a matter of minutes.
Applying the chalk to make a negative
When using stencils, there is often a tough balance between paint thickness and application amount. Too thick of a spray chalk and you will clog your spray bottle but too thin of a liquid and the color will spread beneath the stencil and distort your image.
I like to keep my spray chalk around whole-milk thickness and apply light amounts over a stencil.
To make a simple negative stencil, I buy dense wooden or plastic letters from my local craft store that spell out a word. After placing them in order, gently mist the spray chalk over the letters from a couple feet away. This will ensure that the liquid doesn’t distort the letters. The end result will look like a graffitied version of your message.
Life of the chalk - how long does it stick?
In the past, some chalk has stuck around longer than others. If the design is applied under a rain cover of some sort like a doorway or a tree, the life-span of the chalk will be longer than those in the open.
