Gearing up for July 4th? We've discovered that you can make a homemade skyrocket out of sugar, potassium nitrate, and a few odds and ends. It may be small, but trust us, it's a high-flyer and the materials are cheap and easy to find. Best of all, while anybody can buy a bottle rocket, making one yourself gives you major street cred.
Begin by making the rocket body. Wind a 1.5"×8" piece of brown paper, cut from a grocery bag, around a 3/8-inch dowel. Apply an overcoat of plastic tape to the paper to prevent unraveling, then remove the rocket body from the dowel.
Next, construct a ¼-inch thick rocket nozzle inside the rocket body by holding the rocket body vertically on a heavy table. Then place a few pinches of crumbled kitty litter in the tube and compress it into a hard plug by reinserting the dowel in the tube and striking the dowel lightly several times with a hammer. Use and awl or handheld 3/16-inch drill bit to make a nozzle hole in the center of the plug.
Next, weigh 9 grams of potassium nitrate and 6 grams of sugar and place them in a small, tightly covered plastic container along with five or six lead fishing weights. Put on your safety glasses and then shake, shake, and shake some more. The more you shake the better.
Now go outdoors to complete this project or risk filling your kitchen with smoke should you ignite the fuel. On an an electric hotplate (no gas flames allowed!) heat a pan to medium.
Add the rocket fuel mixture to the pan. Stir with a plastic spatula. The mixture will soon melt into a runny paste. Turn off the heat and let the fuel cool until you can just handle it with your fingers. Working quickly, push the pliable rocket fuel mixture into the rocket body, and then compress it with the dowel and hammer. Let it cool and harden.
Insert the awl or 3/16-inch drill bit into the hole in the nozzle, and drill into the hardened fuel about 2/3 of the way through, then remove the drill. Seal the end opposite the nozzle with a piece of tape.
Create a balancing stick by attaching a 12-inch wooden shish-kebab skewer with tape to the rocket casing behind the nozzle. Find a safe place to try out your rocket. It is impossible to predict the trajectory, so launch only in a flat, open space away from people and ignitable materials. Obey local laws and make sure you have the landowner’s permission to launch.
Insert a 2-inch-long piece of visco fuse into the rocket’s nozzle. If necessary, slightly bend the end of the fuse before inserting it so it stays in the nozzle. Place the rocket in empty glass bottle, light the fuse and retreat to a safe distance.
Projects like this can be dangerous, so attempt only at your own risk. Do not scale up. Use an electric hot plate only, heat the chemicals outdoors only, keep a fire extinguisher handy, retreat to a safe distance after lighting the fuse, and always wear safety glasses.