How to Make a Smoke Bomb

Have you ever wondered how to make a smoke bomb? It is extremely easy! Here are instructions for making a classic homemade smoke bomb using sugar and potassium nitrate. The smoke bomb is non-toxic. It produces white smoke and purple sparks as it burns, but does not blow up. Also, find other simple recipes and safety tips.

How to Make a Smoke Bomb

This is the classic homemade smoke bomb recipe, which only requires two ingredients: sugar and potassium nitrate. Find ordinary granulated sugar (sucrose, C₁₂H₂₂O₁₁) in the kitchen. Potassium nitrate (saltpeter, KNO₃) is sold in some pharmacies and garden supply stores (as a fertilizer). I use Spectracide Stump Remover from a home supply store. Alternatively, you can make potassium nitrate yourself from a cold pack and salt substitute.

This recipe cooks the ingredients together, so you’ll need a skillet. The ingredients are non-toxic, so you can use kitchen utensils. However, the recipe is sticky, much like making candy. If you hate soaking pans, just craft a makeshift pan using foil and throw it away when you’re done.

• Sugar
• Potassium nitrate
• Skillet (or make one using aluminum foil)
• Aluminum foil

Burning sugar makes the smoke while potassium nitrate supports combustion. A good starting point is a 3:2 potassium nitrate to sugar ratio (e.g., 1.5 cups KNO₃ and 1 cup sugar). If you have trouble lighting the smoke bomb, slightly increase the amount of potassium nitrate (5:3 ratio).

1. Pour about 3 parts potassium nitrate to 2 parts sugar into the skillet (5:3 ratio is also good). Measurements don’t need to be exact, but you want more KNO₃ than sugar. For example, you can use 1-1/2 cups KNO₃ and 1 cup sugar. As you approach the 5:3 KNO₃:sugar ratio, you get a smoke bomb that burns more quickly. If you use equal amounts of KNO₃ and sugar, the smoke bomb becomes harder to light and burns slowly.
2. Apply low heat to the pan. If the heat is too high then you can burn the mixture, releasing a lot of smoke! Stir the mixture with a spoon using long strokes. If you see the grains of sugar starting to melt along the edges where you are stirring, remove the pan from the heat and reduce the temperature before continuing.
3. The smoke bomb is done when the solids melt. Once this happens, remove the pan from the heat. There is also a color change, but what matters is that the mixture becomes smooth rather than grainy. During cooking, notice the ingredients change to a golden brown color. Basically, you are caramelizing sugar.
4. Pour the liquid onto a piece of foil. There’s nothing important about the foil. It just provides a convenient surface. You can pour the smoke bomb into any shape, onto an object, or into a mold. The shape and size affects the burning pattern.
5. If you aren’t cleaning the skillet immediately, pour hot water into the pan to dissolve the sugar. Clean up any residue that spilled out of the pan, unless you want mini-smoke bombs on your stovetop.
6. Cool the smoke bomb and peel it off the foil. Now you’re ready to light it!

How a Homemade Smoke Bomb Works

The two ingredients in a smoke bomb are the oxidizer and the fuel. Potassium nitrate is the oxidizer. It supplies oxygen to the combustion reaction and help the fuel burn. Sugar is the fuel. The key to making a great smoke bomb is having a good balance between the oxidizer and the fuel. If there is too much oxidizer, you get a lot of fire (purple, because of the potassium), but little smoke. If there is too much fuel, you get a lot of smoke, but igniting the smoke bomb is challenging.

How to Light a Smoke Bomb

Just take the smoke bomb out to a safe location and light it with a long-handled lighter or match. While you don’t need a fuse, you can add one before the mixture hardens.

Difference Between Homemade and Commercial Smoke Bombs

The smoke bombs you buy at the store are different from homemade smoke bombs. First, a special container disperses the smoke composition. The container has tiny holes so the smoke billows out in a nice cloud. Get a comparable effect with a homemade smoke bomb by covering it with paper or foil and poking holes in the wrapping.

The composition of commercial smoke bombs differs from the homemade smoke bomb recipe. Products from the store typically contain potassium chlorate (KClO₃) instead of potassium nitrate, sugar (sucrose or dextrin – fuel), sodium bicarbonate (otherwise known as baking soda – to moderate the rate of the reaction and keep it from getting too hot), and a powdered organic dye (for colored smoke). When the smoke bomb burns, the heat vaporizes the dye. Pressure inside the device forces out the dye as a cloud.

More Smoke Bomb Recipes

No Cooking Smoke Bomb

• 3 parts potassium nitrate
• 2 parts sugar
• Water

Mix the potassium nitrate and sugar with just enough water so the ingredients stick together. Separate the mixture into separate small smoke bombs (so they dry). Insert a fuse, if desired. Dry the smoke bombs until they feel like clay. This usually takes a day or two.

Powdered Sugar Smoke Bomb Powder

• 3 parts potassium nitrate
• 2 parts confectioner or powdered sugar

Sift the ingredients together and ignite the powder.

Zinc and Sulfur Smoke Bomb

• Zinc filings
• Sulfur powder

Mix the zinc and sulfur. Insert a red-hot wire to ignite the mixture and produce smoke. This smoke bomb doubles as a stink bomb.

Black Powder Smoke Bomb

Mix black powder or pyrodex with other ingredients and ignite them.

• Mixed with sugar and sulfur
• Mixed with sawdust
• With sugar, sulfur, and a bit of material from a road flare (red flame)

Colored Smoke Bombs

Colored smoke bomb use powdered dye. Here’s what you do…

Safety

• Adult supervision is required both for making and lighting smoke bombs! While smoke bombs do not explode, they do burn.
• If you are a messy cook, please make smoke bombs outdoors and not in your kitchen. If you spill the mixture on a burner, expect a lot of smoke.
• Check local regulations before using a smoke bomb. Make sure smoke bombs are legal and that the area is not under a “burn ban”.
• While the ingredients are not toxic, please do not eat the smoke bomb. Even if the sugar is food-grade, the potassium nitrate likely is not.

References

• Moldoveanu, S.C. (November 1998). Analytical Pyrolysis of Natural Organic Polymers. Elsevier. ISBN 9780444822031. 
• Turnbull, Stephen (2004). Ninja AD 1460 – 1650 ([3rd ed.). Oxford: Osprey. ISBN 978-1-84176-525-9.
• Visser, Wouter (November 2003). Practical Pyrotechnics.