How to Make a Smoke Bomb

Materials

To make a smoke bomb, you'll need: 

• Sugar (sucrose or table sugar)
• Potassium nitrate, KNO₃, also known as saltpeter (you can find this at some garden supply stores in the fertilizer section, some pharmacies carry it too)
• Skillet or pan
• Aluminum foil

How to Make a Smoke Bomb

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. If you use equal amounts of KNO₃ and sugar, your smoke bomb will be harder to light and will burn more slowly. As you approach the 5:3 KNO₃:sugar ratio, you get a smoke bomb that burns more quickly.
2. Apply low heat to the pan. 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. Basically, you are carmelizing sugar. The mixture will melt and become a caramel or chocolate color. Continue heating/stirring until the ingredients are liquefied. Remove from heat.
4. Pour the liquid onto a piece of foil. You can pour a smaller amount onto a separate piece, to test the batch. You can pour the smoke bomb into any shape, onto an object, or into a mold. The shape and size will affect the burning pattern.
5. If you aren't going to clean your skillet immediately, pour hot water into the pan to dissolve the sugar (or else it will be harder to clean). Clean up any residue you may have spilled out of the pan, unless you want mini-smoke bombs on your stovetop.
6. Allow the smoke bomb to cool, then you can peel it off the foil.

Now that you've made your smoke bomb, it's time to light it...

How to Use a Smoke Bomb

The solid smoke bomb material is flammable and can be lit directly. You can light your smoke bomb using a lighter, preferably one of the long-handled types used for barbecue grills. Only light your smoke bomb in a well-ventilated area, on a surface that won't catch fire. The smoke bomb will burn vigorously (more slowly with a higher percentage of sugar) with a purple flame.

Alternatively, you could place a short length of fuse into the smoke bomb when you pour it, and then light the fuse.

You can adapt the smoke bomb recipe to make a homemade fountain firework, plus there are additional recipes for smoke bombs...

Additional Smoke Bomb Recipes

No-Cook Smoke Bomb or Powdered Smoke Bomb

A variation on the saltpeter/sugar recipe is to replace the granulated sugar with powdered sugar (icing sugar). The powdered sugar and potassium nitrate are sifted or mixed together and left in powdered form. The powder is ignited to form smoke.

Zinc & Sulfur Smoke Bomb

• Zinc Filings - Zinc Powder
• Sulfur Powder

Mix the zinc and sulfur. Insert a red-hot wire to ignite the mixture and produce smoke. This is a particularly smelly smoke bomb.

Black Powder Smoke Bombs

Black powder (gunpowder) or pyrodex can be mixed with other substances to produce a lot of smoke:

• as a powder, mixed with sugar and sulfur
• mixed with sawdust
• with sugar, sulfur, and a bit of material from a road flare (red flame)

It's easy to make a colored smoke bomb...

Make Colored Smoke Bombs

The recipes for colored smoke bombs require chemicals that may not be readily available unless you have access to a chemistry lab, but it's worth knowing how it's done. Parts or percents are by weight. The ingredients are sifted together and ignited to produce the smoke.

White Smoke Recipe

• Potassium nitrate - 4 parts
• Charcoal - 5 parts
• Sulfur - 10 parts
• Wood dust - 3 parts

Red Smoke Recipe

• Potassium chlorate - 15%
• para-nitroaniline red - 65%
• Lactose - 20%

Green Smoke Recipe

• Synthetic indigo - 26%
• Auramine (yellow) - 15%
• Potassium chlorate - 35%
• Lactose - 26%

Reference: The formulations for colored smoke bombs came from Wouter's Practical Pyrotechnics, who cited the recipes as originating from L.P. Edel, "Mengen en Roeren", 2nd edition (1936).

You can also make a smoke bomb with colored flames...

White Smoke Bomb with Colored Flames

It's fairly easy to make colored flames by adding these chemicals to your smoke bomb recipe:

Chemicals Used to Color Flames

1. Red - strontium salts, most easily found in road flares
2. Orange - calcium chloride (laundry bleaching agent)
3. Yellow - sodium nitrate (common in chemistry lab)
4. Green - barium salts, such as barium nitrate (common in chemistry lab)
5. Greenish-Blue - copper sulfate (common in a chemistry lab, also found in many algicides for pool treatment) Blue - copper chloride (common in chemistry lab)
6. Purple - potassium permanganate (common in a chemistry lab, also used in sewage or water treatment)
7. White - magnesium sulfate (epsom salts, found on laundry aisle or in a pharmacy)

Essentially, you are adding metal salts to get colored flames. You may get additional ideas from looking at the Flame Tests, Fireworks Colors, and How to Color Fire tables. The metal salts listed here produce a relatively safe smoke. Use caution when considering other metals salts, as some compounds may produce toxic smoke.