Making your own sidewalk chalk is a fun and easy project that kids will love. For Valentine's Day, I decided to make heart-shaped chalk and tested it out outside.
Last time, I showed you how I made a portable, foldable chalkboard heart valentine. It's a super-cute Valentine for kids because you can fold the chalkboard up around some chalk and snap it together making it easy to transport the chalkboard and chalk without making a mess. I even made a homemade heart-shaped felt eraser that you could slip inside.
Following the theme, I thought it would be a great idea to give away some heart shaped chalk with it.
I have been meaning to try to make my own chalk, anyway, but hadn't gotten around to it until now.
Watch how my son and I make our own chalk
Making your own sidewalk chalk is a very simple, quick project, and uses only plaster of Paris and water, well, and any colorant that you would like to use to make colored chalk.
Basically, you mix your plaster according to the package directions, or until you get a consistency that you like. (Usually, you should add around 3 parts water to 4 parts plaster.) Then, you add in your colorings until you get the shade you want.
Homemade Sidewalk Chalk
- Mix together the water and plaster until well combined.
- Color the mixture with tempera or acrylic paints or food coloring. Using paints will provide a much brighter color. Mix together until the color has evened out.
- Pour the mixture into silicone molds or cardboard tubes like the ones leftover from finished toilet paper rolls. I used both heart shaped ones (which are great for little hands) and tall thin molds meant for making ice cubes for bottles. They both worked really well as chalk molds.
- Allow the plaster to dry completely.
When I used a lighter plaster, it took a couple of days to harden and dry out enough to take the chalk out of the molds easily.
- Unmold and have fun writing on the sidewalk outside.
How to color your homemade sidewalk chalk
Most sources chose tempera paint powder for coloring their chalk, but I couldn't find it very easily around here and didn't want to have to buy any specifically for this purpose. I was in a bit of a hurry or I would have ordered a bottle online.
Instead, the first time I made this chalk, I chose to use some food coloring that I had sitting around the house. The color isn't as bright as I would imagine a powdered tempera paint would be, but it served it's purpose well enough. Using gel food colorings may also result in a stronger color. This was an old color that I had sitting around and that I wanted to use up.
Because I wanted vibrant, stronger colors, this year we tried adding a liquid acrylic paint, which is what we happened to have on hand, and it worked perfectly.
We ended up with a really bright, vivid colored chalk.
How to shape your sidewalk chalk
Once you have your plaster ready to pour, fill up some silicone molds in your desired shape. With Valentine's Day coming up, I chose to use heart-shaped molds to make some cure, heart-shaped sidewalk chalk. The heart-shaped chalk was great for tiny hands to hold onto.
There was no need to prepare the trays in any way, and when the plaster is set, the heart-shaped chalk pops out easily.
Now that my son is older and wanting to be more precise in his writing, I decided to try some new molds. This year, I used ice cube trays meant for making ice cubes for bottles, and they worked great. The resulting chalk is long and narrow, making it perfect for easier writing for kids who are used to holding a pencil or pen.
I let mine sit overnight, just to be on the safe side, and the next morning I excitedly popped the chalk out, ready to give it a try. This year, though, when I used a lighter plaster, I actually had to wait for a couple of days to take out some of the pieces of chalk.
Does Homemade Sidewalk chalk work?
With it being wintertime, I began inside and tried it out on my foldable heart chalkboard valentine. I was a little bit discouraged, though, to see that it wasn't leaving much of a mark. 🙁
(Update: I was able to get it to work with a lighter, less dense plaster.)
I sadly gave up on the idea of using the heart-shaped chalk with my heart-shaped chalkboard valentines. In hindsight, the heart chalk was much too big for such a small chalkboard anyway. It would have been cute to have it all work together, though.
I wasn't going to give up on my heart chalk completely, though! It was time to take it outside and use it as most people do… as sidewalk chalk.
On the sidewalk, my heart-shaped chalk worked much better. In fact, it worked quite well!
The problem with homemade chalk is that plaster, at least the type I used, is more dense and compact than regular store-bought chalk. Just by comparison, it weighs more. (Of course, that could also due to the fact that it was still holding moisture.) The sidewalk and our tiling outside both provide a rough enough surface for using our homemade sidewalk chalk quite easily.
Choosing your plaster for making chalk
When I first made the heart-shaped chalk, I used a regular plaster (the so-called “escayola” here in Spain). This year, I decided to use what is called “yeso” in Spanish. It's lighter and not-so-hard. It took longer to set and dry, but worked perfectly as a normal chalk would. I was even able to use it on my homemade chalkboards.
For reference in English, I think that plaster of Paris is the lighter type of plaster that you want to use to make chalk. Certain plasters meant for making repairs may make a much harder type chalk. Those chalk are more heavy-duty and harder to break, but also harder to use. They also will only work on harder surfaces like the ground outside.
Because the plaster will hold moisture for at least a few days or so, you will notice that it is still a bit tricky to use on the first day(s) after you make it. If you draw on the sidewalk, the chalk will leave its mark, but it doesn't show up completely until a minute or two later when the plaster dries. As the chalk dries out more, it gets easier to use.
My son had a lot of fun playing with it. (As did I, as you may be able to tell.)
After making this several times, spaced out over several years, I have to say that it's a very fun activity for kids of all ages. Kids love being able to make something that one would normally buy. By making it themselves, they can choose the shapes and colors in which to make their homemade chalk, and are proud to say that they made it themselves!
If anybody has any more tips and tricks for making a light, easy-to-use chalk (which plasters are best in the US, for example), I'd love to hear your ideas!