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Make homemade liquid sidewalk chalk for your little ones to paint with outside.
Approximate Time: 5 minutes
Sidewalk chalk is sometimes expensive and not always easy to find. Mix 1 cup Plaster of Paris with 3\4 cup water and powder tempera paint of your color choice. Pour into an egg carton container, and let harden for 24 hours. Pop the molds out and enjoy. The shape of the sidewalk chalk is easy for smaller hands to use.
You can only purchase the 3 primary colors of tempera paint (red, yellow, and blue) and mix the powders together with the plaster and water to create so many beautiful colors. It makes a great science experiment too for the young ones!
By Marci from West Monroe, LA
Make your own sidewalk chalk.
Source: I found this on a thrifty site, but I can't tell you the name (I visit so many!)
By Monique 
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Here are questions related to Homemade Sidewalk Chalk.
Could you use food coloring, for the colors or do you have to use the paint?
Does the liquid sidewalk chalk stain concrete? I wanted to make it for my son and let him paint the driveway.
By Joan B.10/26/2011
I have never seen any stained sidewalks from the purchased sidewalk chalk, but I don't know about the home made sidewalk chalk.
How do you make chalk?
Here is one from right here at Thrifty Fun: http://www.thriftyfun.com/tf494134.tip.html
'Plaster of Paris' is available at craft stores, hardware stores, Kmart etc.
Thrifty Fun has been around so long that many of our pages have been reset several times. Archives are older versions of the page and the feedback that was provided then.
Mix the water, Plaster of Paris and powdered tempera paint. The more tempera paint you add, the deeper the color of the chalk will be. Then pour the mixture into you mold.
Toilet Paper Roll: A toilet paper roll works as a mold. Just seal one end with duct tape and pour the mixture into the mold and let it dry. When I use toilet paper rolls I like to let it dry for over 24 hours. You can line the toilet paper roll with wax paper so that the chalk will easily slide out.
Egg Cartons: Egg cartons are nice because you can do numerous different colors in one mold.
Dixie Cups: 5 ounce dixie cups also work well.
Film Cannisters: Just line with wax paper and the chalk will slide right now.
Note: Be sure to follow all safety precautions on the Plaster of Paris box. And, this makes a mess!
By Cheryl from Missouri
Another thought, gently tap, tap, tap the poured molds to get the air bubbles out of. Do not hasten the drying process mechanically (like with hair dryer, microwave, etc). WHY do I say that? With my big projects I have done that, fine. With small ones it does not work. (07/07/2010)