The classic smoke bomb is a great project for the home or lab, producing lots of safe smoke, with purple flames. If you get dye and consider the shape of your creation, you can make a smoke bomb that billows clouds of brightly-colored smoke. This project is easy and safe enough to do at home. Adult supervision is required.
60 g (3 tablespoons) potassium nitrate (sold as saltpeter in garden supply shops) 40 g (2 tablespoons) sugar 1 teaspoon baking soda 60 g (3 tablespoons) powdered organic dye (found in laundry sections of the store as well as craft & hobby shops) cardboard tube ( an iced push-pop tube works (eat the treat first), or you could use a toilet paper roll or section of paper towel tube. duct tape pen or pencil firework fuse from hardware, rocketry, construction, or hobby shops, or scavenge it from a firework (just make sure it is not broken or it will dud) cotton balls saucepanedit Steps
1Mix 60g potassium nitrate with 40g sugar in a saucepan over low heat. It's a 3:2 ratio, so if you don't have a method of measuring grams, use three tablespoons of potassium nitrate and two tablespoons of sugar.
2The sugar will carmelize and brown. Stir the mixture continuously until it resembles smooth peanut butter. I you are having trouble getting the sugar to caramelize, try adding some parrafin candle wax. Add just enough so that all of the powder in your pan is wet when the parrafin is melted. When using parrafin, there is no need to caramelize the sugar; just let the parrafin melt while mixing it and pour it into your tube once it's all melted and mixed.
3Remove the mixture from heat.
4Stir in a spoonful of baking soda (rounded teaspoon is fine). The baking soda is added to slow down the combustion when the smoke bomb is ignited.
5Add three large spoonfuls (3 tablespoons) of powdered organic dye. Blue dye and orange dye are said to produce better results than the other colors. Stir to mix well.
6Construct the smoke bomb while the mixture is still hot and pliable.
7Fill a cardboard tube with the warm smoke bomb mixture.
8Push a pen or pencil down into the center of the mix (doesn't have to be all the way to the bottom but should be enough that the pen stands in the mixture). You could use a different shape, but the cylinder works really well.
9Let the mixture harden (for about an hour).
10Remove the pen.
11Insert a firework fuse. Push pieces of cotton balls into the hole to tamp the fuse securely inside the smoke bomb. Be sure there is fuse left outside of the tube so that you will be able to light your smoke bomb.
12Wrap the smoke bomb with duct tape. Cover the top and bottom of the tube, too, but leave the hole area with the cotton and fuse uncovered.
13Go outside and light your smoke bomb!