Making your own sidewalk chalk is lots of fun. We chose to make dinosaurs but you could make any shapes. Wrap them up in little box and some coloured cellophane to make a cute present or party favours.
Time: 15 minutes plus at least 3 days drying time
Age: Any Age
Tempera paint powder works best to give an even colour but it is quite expensive. Liquid tempera (poster) paint also works well enough- we used liquid paint here.
We tried small molds (ice cube sized) and jumbo molds (muffin sized). We preferred the smaller finished chalks as they dried much faster.
We preferred the small dinosaur chocolate mold which cost 2 dollars from the local supermarket
We made up our plaster using a ratio of 2 parts plaster powder to 1 part water.
If you're using liquid paint, add around 1-2 teaspoons of paint to half a cup of water and mix well. Pour into a disposable tub and add 1 cup of plaster of Paris powder, stirring well until the color is mixed through.
With liquid paint, add the paint to the water first...
...then add plaster powder and stir
If you are using powder paint, stir the paint through the plaster powder first then add the powder mix to water.
The consistency should be thick but still pourable
Pour into silicone molds and leave to set.
You should be able to remove the casts from the molds after 24 hours. Leave the chalk to dry out for at least 2 more days before you use it. Bigger shapes may need even longer drying time.
Your sidewalk chalk is now ready to use - have fun!
Jumbo dinosaurs took quite a few days to dry out
We also made pretty multi coloured stars by adding a small layer of one colour, leaving to set slightly, then adding a layer of another colour
Notes Use a disposable tub to mix the plaster - you can then throw away the tub after you have finished. As it could set in pipe work, you won't want to wash any down the sink. Be careful not to inhale plaster dust and try to minimize skin contact with wet plaster.