How to build a simple Smoke Bomb using basic kitchen and garden shop chemicals...
We made smoke bombs back home
We made homemade smoke bombs by combining two simple and readily-acquired ingredients and 'cooked' the dry mixture in an old skillet, all done outside of course. A little basic chemistry know-how and a few dollars worth of basic kitchen and gardening chemicals and you have all the ingredients you need.
First it shall be said, do no attempt this in your mom’s kitchen, or in the home for that matter. You are working with mildly noxious chemicals and heating them in a skillet over either a flame or electric heating element. This basic chemistry lesson and project is best performed outside or in the garage, and with goggles, gloves and protective wear for your face and eyes.
Ingredients for the Smoke Bomb are as follows:
- Plain white granulated table sugar (sucrose)
- Saltpeter, also known by the chemical name potassium nitrate. (“fertilizer” and “tree stump remover” are potential sources of saltpeter.)
- A sheet of heavyweight aluminum foil, and
- An old skillet (preferable a discarded cast iron skillet that won't be used for other purposes)
- Baking soda (sodium bicarbonate.) This ingredient slows the rate of burning, making the smoke bomb last a little longer when ignited. Optional but preferred.
Smoke Bomb Creation Method:
Using a small measuring cup (a 4-or-6-ounce ‘Dixie cup’ can used for the purposes of equal parts measuring,) combine approximately 3 or 4 measures of white sugar to 2 parts potassium nitrate. You need the ratio to favor white sugar over potassium nitrate at either a 3:2 or 4:2 ratio or else the result will be harder to ignite.
Sugar is the ‘fuel.’ Potassium nitrate is the ‘oxidizer.’ Too much potassium nitrate and the smoke bomb will burn too quickly. You want the effect to last long enough to appreciate. Also add one level teaspoon baking soda to the mix before 'cooking' to slow the rate of burning of the finished produce (entirely optional ingredient.)
Have the aluminum foil prepared: laid out flat and secure on a flat surface (board, etc.) to receive the ‘smoke bomb cookies’ that we will be placing upon it to cool.
In the skillet, combine the ingredients over heat and stir with a wooden spoon or spatula. Mix and fold gently. You will see the sugar beginning to caramelize (‘melt’ and brown.)
Remove the skillet from the heat and continue to blend the Smoke Bomb mixture until it becomes a nice caramel brown to darker cocoa-like color.
Continue to stir off and on the heat until smooth and creamy like warm peanut butter. Don’t overheat the mixture; you don’t want it to ‘smoke’ or worse, to ignite! There might be some odor during this ‘cooking phase' which could be objectionable (which is why I recommend doing this outside only!)
When the mixture is blended and looks adequately smooth and creamy, spoon individual portions onto the aluminum foil sheet into little mounds about the size of a walnut or plum. There is no need to press these flat like cookie dough although this is what the mixture will remind you of, cookie dough. If used aforethought, bust apart a long wax candle and salvage the wick.
Cut the wick into inch-long pieces and have ready on-hand. Using a pair of needle nose pliers and wooden stick (a Popsicle stick works fine) gently press one end of the wick into the still soft smoke bomb material. This provides a ready-made wick for lighting the smoke bomb. The still-hot material will harden around the inserted wick end quite nicely.
Keep in mind that the melted sugar mix will be very hot even minutes after having been set onto the aluminum foil. Do not touch it with your bare skin for it will stick and burn you quite badly!
If you plan to use the candle wick option, you can also space the placement of the hot smoke bomb cookies far enough apart on the aluminum foil so that when cool, you can cut and wrap the foil around the smoke bomb, leaving just the wick exposed. Think 'Hershey's Chocolate Kisses' and you've got the idea.
Allow these Smoke Bomb Cookies to Completely Cool.
When cooled, peel the smoke bombs from the aluminum foil. The foil may stick to the bottom. This won’t affect its function.
Light that Smoke Bomb!
These can be easily lit using a wooden match or long-necked propane candle lighter. Only ignite these outdoors, and upon a non-flammable surface (a flat rock, concrete brick or patio step, etc.) and away from the house. They will readily ignite and smoke profusely. The smoke will be dense and abundant. The smoke bomb will only last for 10 or 15 seconds for the size smoke bomb that we have made.
Colored Smoke Bombs?
If you are brave (and careful enough!) to perform this basic chemistry lesson, it is a nifty little do-it-yourself pyrotechnic effect for your homemade smoke bomb creations which can liven your Fourth of July backyard party or other patriotic event. Colored smoke requires chemicals that may not be readily available to the average user, but they can be sourced from products that contain them. Additional research is called for. Experiment, -discover what works!
Use caution when making this concoction and be mindful of local ordinances about creating and igniting pyrotechnic devices in your community. I present this how-to for the knowledge only. It is your responsibility to know your local laws regarding smoke bombs.
Be safe! Have fun!