Make Sugar Rockets

Sugar rockets sound innocuous, but they produce thrust that can lift them hundreds of meters in the air. This article will show you how to make them.

10 Second Summary

1. Cut a short piece of PVC piping and add a retaining ring to each side.
2. Pack the PVC piping with ground cat litter.
3. Heat ground potassium nitrate with powdered sugar in a saucepan, stirring frequently.
4. Pack it into the rocket and add more cat litter.
5. Drill a hole through the litter and attach a fuse.
6. Attach a stick to the side, set it in the ground, and light it.

Steps

Making the Rocket Body

1. Cut short sections of PVC piping. Buy roughly 13 mm (½ inch) diameter PVC piping from a home improvement store. Cut-PVC-Pipe into sections, as long as you'd like your rockets to be. 7.5–10 cm (3–4 in) rockets are a good place to start.
   • Do not replace this with a metal pipe. Sparks from the metal could ignite your rocket and cause a premature explosion.
2. Add a retaining ring to each side. Find a smaller PVC pipe, that just barely fits into your rocket sections. Cut this into short sections, about 6–12 mm (¼–½ in) long. Cut through each section — this allows you to expand the ring outward for a tighter fit. Apply PVC cement to the inner edge of the larger pipe, at one end. Place the smaller pipe inside the larger one, pressing it outward to form a tight fit. Repeat on the opposite end with a second retaining ring. Clamp and wait for the cement to cure, according to label instructions.
3. Grind cat litter. Purchase unscented clay cat litter from a pet store. Keeping it dry, grind it in a coffee grinder or mortar until it becomes fine dust.
   • Alternatively, use quick-set cement.
   • Eventually, you'll be making a cap on the opposite end as well. Grind extra and set it aside.
4. Pack the litter into each rocket. Stand each pipe on its end on a stable surface. Fill each one about ⅓ full with the cat litter dust. Tamp the litter vigorously with a wooden dowel or spool that fits snugly into the pipe. This should compress the litter into a hard, clay cap.
   • Make sure the clay forms a hard surface above the retaining ring. The ring's job is to prevent the clay from sliding out, allowing the rocket to build up more pressure before the cap blows out.
   • If the litter crumbles and refuses to pack, dampen it slightly.

Making the Propellant

1. Purchase powdered sugar. Sugar provides the energy that will give thrust to the rocket once burned. Check the ingredients list before buying: most powdered sugar contains a little corn starch, but this will not significantly affect the rocket. If it contains any other additives, look for a different brand.
   • In some areas, this is sold as confectioner's sugar or icing sugar.
   • You can start with granulated white sugar and Make-Powdered-Sugar with a blender, coffee grinder, or spice mill.
2. Find potassium nitrate. This chemical, KNO₃, will provide oxygen to allow for fast, prolonged combustion. Buy this as "stump killer" at a garden supply store or home improvement store. Some brands of stump killer contain other ingredients, so check the label to make sure it is 100% KNO₃.
   • You can sometimes find potassium nitrate at pharmacies, farming supply stores, or online chemistry supply stores. For best results, look for it in powdered form.
   • Keep the potassium nitrate and the sugar in separate rooms.
3. Grind the potassium nitrate to a powder. Buy a new coffee grinder and label it "potassium nitrate." Place it on a cleared counter, far away from all sugar and combustible materials. Fill halfway with potassium nitrate and grind for about 40 seconds, rotating the grinder to make sure all the powder hits the blades. The finer the powder, the more evenly it will mix with the sugar.
   • Never grind sugar and potassium nitrate in the same grinder, even in separate batches. This can cause a fire or explosion.
   • You'll need 65g (2.3 oz) for this batch, about a handful.
4. Find an appropriate work area. Once made, the rockets are at risk of combustion if they come into contact with heat, a spark from a metal object, or a flame. Ideally, you should make the rockets close to the area you plan to set them off. Choose an open area with no passersby. Even when intentionally set off, these rockets can damage surroundings or people when they return to earth.
   • Check local law for regulations concerning rockets or fireworks.
5. Set up an electric heating station. Soon, you'll be mixing the two ingredients together over heat. There's always the risk of explosion or fire during this process. Reduce the chance of injury with the following setup:
   • Remove all clutter and flammable materials from a spacious area, preferably outside. The floor should be made of dirt (with all weeds removed) or concrete.
   • Set up an electric hot plate or deep fryer with a thermostat control. An electric stove or other heating element without an exact temperature setting adds significant danger.
   • Make sure there are no sources of sparks or open flame in the area. Even metal objects can be dangerous.
   • Keep a large container of water nearby. A fire extinguisher may not extinguish burning propellant.
6. Wear safety equipment. There's a significant chance that the propellant mixture catches fire and explodes violently. Wear gloves, a face shield, and thick clothing that covers all exposed skin. Do not wear any clothing made from synthetic materials, which can melt onto your skin.
   • Use a face shield that protects your head and hair as well.
   • A leather apron and long leather gloves are recommended.
7. Add ingredients to a heat-safe container. Use-a-Scale, measure 65 grams (2.29 ounces) powdered potassium nitrate, and bring it to your heating station. Bring the kitchen scale to the powdered sugar. Measure 35 grams (1.23 ounces) powdered sugar in a new container and bring that to your station. Pour both ingredients into a saucepan or frying pan that you don't plan on using for any other purpose.
   • For best results, make a double boiler by placing a deep saucepan into a larger pan filled with oil. This heats the propellant more evenly.
   • For your first project, consider using 60g (2.12 oz) potassium nitrate and 40g (1.41 oz) sugar instead. This is much easier to make, but less powerful.
8. Mix with baking soda (optional). This will slow down the firing, which decreases thrust but reduces risk of exploding the rocket prematurely. Mix 15g (0.53 oz) baking soda into your 100g (3.5 oz) of propellant. Use a wooden or silicone implement to stir.
9. Heat while stirring frequently. Place the container of sugar and potassium nitrate on the electric heat source. Heat at 193ºC (380ºF), staying as near to this temperature as you can the whole time. Using a silicone spatula (never a metal one), stir gently to combine the two ingredients and distribute the heat. Failure to stir frequently can cause an explosion. Stir over heat until the whole mixture turns into a thick, light brown paste, similar to peanut butter. This can take up to an hour, but a batch this size will usually be ready in 20–30 minutes.
   • If the sugar turns dark brown, remove the mixture from heat. Too much caramelization will make the propellant less effective.

Finishing the Rocket

1. Pack the propellant into the rocket body. As soon as the hot propellant mixture is ready, pour a little into one of your prepared rockets. Immediately tamp it down with a snug-fitting dowel, making sure there are no air bubbles. Pour more propellant and tamp down until there's roughly 2.5 cm (1 inch) of space left in the tube.
   • If the mixture has cooled too much to pour, transfer the material with a wooden implement.
   • Leave space between the propellant and the retaining ring.
2. Tamp down additional cat litter. Create a second clay cap on top of the propellant, just as you did the first. Tamp down firmly to create a hard, non-crumbling cap. This should extend beneath the retaining ring and lie even with the end of the rocket.
   • Again, you may use quick-set cement instead. Allow cement to cure before you continue.
   • At this point, the rocket will move with extreme force if the propellant ignites. Stand back while tamping. From now on, treat the rocket with extreme caution and avoid pointing either end toward yourself.
3. Drill carefully through the top cap. It's time to turn the cap you just made into a nozzle, which will create thrust by expelling high-pressure exhaust. It is possible to ignite the rocket by drilling, so use extreme caution. In your fire-safe work area, drill the nozzle as follows:
   • Clamp your rocket in place and stand to one side. Never put your face in front of the rocket end.
   • Choose a small drill bit, to make a small hole in the center of the rocket. A smaller hole leads to higher pressure, but this may blow off the cap prematurely. You may need to experiment to find the best results.
   • Use the slowest drill setting to keep temperatures low. Drill through the center of the clay cap. Stop every few seconds and withdraw to reduce heat and wipe off stuck particles with a dry cloth.
   • Drill until you penetrate the top cap.
4. Create a core (optional). After you've penetrated the cap, you may wish to create a hollow core in the propellant. This will increase thrust by providing more surface area to combust. Push a dowel or aluminum rod into the propellant, pushing about halfway along the rocket's length.
   • Your propellant may be too viscous or too hard to create the core. That's fine; the rocket will still work.
   • Remember, do not put your face in front of either end of the rocket.
5. Attach a fuse. Thread a cannon fuse into the hole you just drilled. Leave plenty of fuse outside the rocket for safety.
6. Attach a stick to the side. Tape or glue a long, sturdy, wooden skewer to the outside of the rocket. Attach it near the nozzle, with most of the skewer extending beyond it.
   • You should be able to balance the rocket (just above the ground) on a finger placed just above the nozzle. Move the stick or switch to a stick of a different size until you can balance it.
7. Set in the ground and light. Plant the stick firmly into the ground so the rocket points upward. Confirm that the stick and rocket are stable. Warn everyone in the area. Light the fuse and step well back. Congratulations! You've launched your first sugar rocket.
   • Preferably, move behind a safety wall after lighting the fuse.

Tips

• Store all ingredients and propellant in an airtight container to minimize the amount of moisture they absorb from the air. (To reduce fire risk, only store propellant for a day or two, while completing the project.)
• If your stump remover is not 100% KNO₃, dissolve it in boiling water and strain it through a paper filter. Discard the filter and solids, then boil off remaining water to get mostly pure KNO₃. Leave in a hot area or minimum-temperature oven until completely dry.
• For an extremely fine powder with excellent combustive qualities, put the sugar and the nitrate (always separated) into individual rock tumblers. Tumble for up to 10 hours.
• Kids should not try this at home. Have children stand 20 feet away from the rocket.
• Gluing fins will drastically increase stability.
• Your wall for protection should be made out of bricks and be firmly placed on the ground.

Warnings

• This is a highly dangerous process that should be treated with caution. Older children should not try this without constant, close supervision. Younger children should not be kept near the area.
• Check local laws before making or firing rockets. They may be considered fireworks or weapons in some areas.
• If anyone else has access to your workspace, post visible warning signs at all entrances.

Things You'll Need

• PVC pipe, about 13 mm (½ inch) diameter
• PVC pipe, about 6 mm (¼ inch) diameter (tight fit in the larger pipe)
• PVC cement
• Clay cat litter or quick-set cement
• Wooden dowel or spool (tight fit in the larger pipe)
• Potassium nitrate (KNO₃)
  • Easy to make recipe: 60 g (2.12 oz)
  • More powerful recipe: 65 g (2.29 oz)
• Powdered sugar
  • Easy to make recipe: 40g (1.41 oz)
  • More powerful recipe: 35g (1.23 oz)
• Baking soda, 15g (0.5 oz) (optional)
• Electric deep fryer or hot plate with thermostat control
• Face shield
• Gloves and thick clothing, non-synthetic (preferably flame-resistant)
• Drill
• Vice or clamp
• Kebab stick

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