This instructables goal is to allow you to make "rocket candy" or "caramel candy" for easy, quick rocket fun! Rocket Candy is composed of two basic ingredients. Sugar and Potassium Nitrate, both of which can be found the home or at a home improvement store. WARNING rocket candy is dangerous and can harm you if you are not careful. Use safety precautions to keep yourself safe. Wear eyewear at all time while making the fuel. Wear gloves when working with the fuel. Keep the fuel from and open flame and never attempt to light the fuel indoors. Rocketry is an outdoor activity. The creator of this instructable is not liable for any injury that occurs while making rocket candy. In order to make rocket candy you will need:
- Potassium Nitrate (KNO3)
- Scale or balance
- Mortar and Pestle
- Electric skillet
- Glue Stick
- Electric Drill and bits
Step 1: Constructing the Engine
For this step use a glue stick, paper, scissors and a pen. Use the scissors to cut a strip of paper 1"- 1 1/2" thick by 11 inches long. Then use the glue stick to coat both sides of the strip with glue. Use the pen, and wrap the paper around the pen to form a cylinder. This cylinder will act as your engine. Then use the clay to plug up one end of the engine. Repeat this step for as many engines required. Allow the engines to completely dry before packing them with fuel. The glue will provide rigidity and structure.
Step 2: Ingredients
First the basic ingredients must be obtained. Sugar and Potassium Nitrate will be required for the fuel. The sugar can be found at any grocery store or mini market. Potassium Nitrate can be found at Lowes however it is labeled as Stump remover. Spetracide stump remover is reccommended as it is 100% Potassium Nitrate. The potassium nitrate acts as the oxidizer in the fuel and the sugar acts as the fuel.
Step 3: Grind
The Potassium Nitrate will need to be grounded into a fine powder. This will increase the surface area and provide a clean and quicker burn when lit. To grind the potassium nitrate pour about 15 grams into a mortar and pestle. Grind the Potassium Nitrate into fine granules. This will take about 20 minutes to do correctly.
Step 4: The Golden Ratio
Now that you have fine granules of Potassium Nitrate, you can begin to weigh out the fuel. The optimal ratio of oxidizer (KNO3) to sugar should be 65:35. To obtain the correct amount use a scale and weigh out 65 grams of Potassium Nitrate and 35 grams of sugar.
Step 5: Mix and Heat
Now that you have the correct ratio of oxidizer to sugar ratio mix the two components together. Mix thoroughly. Next you can evenly spread the fuel throughtout the electric skillet.
Step 6: Caramelization
Heat the electric skillet to about 375 degrees. The melting point of sugar is 366 degrees. The goal is to caramelize the sugar and coat the fine granules of potassium nitrate with the sugar. This will provide and even mixture for the fuel. Within 5 minutes the powder in the skillet will liquify and become gooey. Mix the gooey mixture around in the skillet until it is the consistency you would like. To thicken the consistency turn the heat down and to liquify the fuel turn the heat up. Avoid heating the fuel up too much because charring decreases the effectiveness of the fuel.
Step 7: Engine Packing
Now thet the fuel is pliable the engine can be packed. Since the engine was modeled around the diameter of a pen, a pen can be used to tighly pack the engine. Use a glove to protect your hand as you pack the engine. Caramelized sugar can severely burn your hand. Place fuel inside the engine and using the end of a pen pack the engine periodically. Pack the fuel to the top of the of the engine. To ensure a steady burn avoid having air bubbles in the rocket motor, these can cause unstable flight or explosion.
Step 8: Engine Prep
After allowing the rocket engine to cool, the engine must be incorporated into a rocket. To do this first drill a hole in the base of the engine to create a nozzle which will direct the flow of the gases and provide the thrust for your rocket. You will want about a 1/16" drill bit to obtain the correct nozzle size, and the hole should be about half the engine length deep. This hole will also provide an ignition site for the electric igniters. Also tape a stick to the side of the engine to create a bottle rocket.
Step 9: Igniter
Place the igniter within the hole that was drill in the previous step. Then place a plug in the base of the hole to ensure the igniter stays in place. After this step you are ready to launch your rocket. Head outside to see how your rocket performs!!