Of course, you don’t exactly know all that’s in that one-buck sidewalk chalk, nor do you know the conditions of the workers who manufactured it. That aside, however, there’s also just something to be said for fostering the D.I.Y. ethic in your life. When you make homemade sidewalk chalk, you can make it any color you want, using your own pigment that you’re comfortable with. You can make it practically any shape you want, using anything from muffin tins to toilet paper rolls. And if you’re making your chalk for a kiddo, well, then that kiddo can actually practically make this chalk recipe all by herself, and then that kiddo will grow up knowing one more thing she can make for herself instead of having to buy. So gather up your toilet paper rolls and your muffin tins, because this sidewalk chalk recipe is easy. It’s cheap. And you’re going to love it: To make homemade sidewalk chalk, you’ll need plaster of Paris, molds for the chalk, soon-to-be disposable mixing containers (I use stuff that we’re about to throw away or recycle, anyway), and pigment. For pigment, you can use whatever you have on hand–some ideas are food coloring, liquid watercolors, or powdered tempera, which is what I usually use. Follow the recipe on the package of plaster of Paris to mix up perhaps two cups’ worth, then add your pigment. If you, too, are using powdered tempera, start with one tablespoon, and gradually add more until you’re satisfied. Whatever pigment you use, liquid or powder, you’ll slightly throw off the proportions in your plaster of Paris mixture. This is actually a good thing, because then the plaster will set a little softer, making a better chalk. If the mixture becomes too thick to pour because of dried pigment, or too watery because of liquid pigment, simply stir in more dry plaster or water until you have that pancake batter consistency back. Next » Step 2 It’s unlikely you’ll need to do much to prepare your molds in any special way. Silicon molds can be turned inside-out to unmold your finished chalk. Regular muffin tins can be turned upside-down and given a good thump. Cardboard containers used as molds can simply be peeled off of the finished chalk. To make a nice, big chalk stick, seal one end of a toilet paper tube, a cut-down paper towel or wrapping paper tube, or the long, narrow box that a tube of toothpaste comes in with duct tape. To make other shapes of chalk, search your recycling bin for other likely containers–if the container can be ripped or cut, then you’ll be able to unmold your finished chalk just fine when it’s set. When you have your molds and your plaster of Paris mixture ready, simply pour the dyed plaster into each mold, thump the mold onto your work surface a few times to release any bubbles, and let it rest until it’s set, which will likely take longer than indicated by the directions on your plaster of Paris package, since you’ve added in that pigment. Next » Step 3 NOTE: Don’t you dare pour any unused plaster of Paris down your drains! You can take containers outside and rinse them out with your garden hose, or wait until the plaster has set on a container and then chip it off, but in our house we tend to use stuff that’s on its last legs, anyway–the cups that came with our take-out pizza, old paint stirrers or sticks from the yard, rinsed-out deli containers, etc. In the same vein, don’t wash your molds until you’ve thumped off all the dried plaster around their edges. Cardboard molds can be dropped back into the recycling bin, but if you’ve cut up a recycled plastic mold so much that it no longer has its recycling number on it, you’ll likely have to toss it in your regular trash. Next » Step 4 Let your unmolded, finished chalk set out a few more hours to cure, then it’s ready to use!
