What is rocket candy?
Rocket candy is a type of fuel used for model rockets that is made from sugar and an oxidizer. Rocket candy, aka caramel candy, is called such because of its sugar content and appearance of caramel. Because of its oxidizer content it obviously should not be consumed.
-Beaker/ Heat safe container
-Hot Plate/ Electric Skillet
-Mortar and Pestle/ Grinder
-Used rocket motors
-Drill and Drill bits
-Model Rocket, Igniters, Launch Pad, etc
-Safety Gear (goggles, gloves, etc)
Making rocket fuel is dangerous. There is potential for personal injury including poisoning and burning. This is to be conducted outside under adult supervision and in an open air environment. The creator of this instructable is not personally responsible for any injury resulting from the creation or use of this rocket candy. All safety precautions should be followed including those of the manufacturers of the rockets themselves. Take care, while fun, rockets are still dangerous.
Step 1: Ingredients
This specific type of rocket candy calls for 3 ingredients. An Oxidizer, Potassium Nitrate (KNO3, aka "Salt Peter"). And two types of fuel: Sucrose (table sugar), and Fructose (Corn Syrup). Ideally the oxidizer and fuel should be in a ratio of around 65:35. In order to account for the water in the corn syrup, the ingredients should be in the following amounts:
Sugar and Corn syrup can be purchased at your local grocery. KNO3 can be found in commercial stump remover which can be purchased at most hardware stores or online.
Weigh out the ingredients on the scale.
Step 2: Heat
Turn on your hot plate to around 350 F and allow it to heat up.
Step 3: Add the Ingredients
Add your ingredients to the beaker. Stir continuously until the mixture is a uniform consistency. Then stir occasionally so that the sugar doesn't burn.
Step 4: Turn the Heat Up
Once the mixture has thinned out a little (after about 5-10 mins) increase the heat to 500-600 F. Stir more often than before.
Step 5: Remove From Heat
Once the mixture stops bubbling and has turned a caramel color (after about 15-20 mins) turn off the hot plate and remove the beaker from the heat. Pour your mixture onto wax paper and let cool.
Step 6: Cool Your Fuel
Once the fuel has cooled and hardened break it into smaller pieces. You will notice the fuel has lost some weight due to water boiling off.
Step 7: Grind Your Fuel
Using a mortar and pestle, grind your fuel into a powder. This step is important. The fuel must have a small grain size so that it can be properly mixed and packed.
Step 8: Add Metal Oxide
Add 5-10% by weight of a metal oxide. This increases the burn rate of your fuel turning it from a smoke bomb into a rocket engine. The easiest metal oxide to use is Iron oxide (rust). There are plenty of great tutorials on Instructables.com on how to make rust. It follow the instructions and add the rust to your fuel and mix.
Step 9: Pack Your Motors
Take the motor casing from a used rocket motor and fill it with your fuel. I used the B size rocket motors which take around 6g of fuel to fill. While packing you should periodically pack down the fuel in the motor. Do this by sliding the dowel rod into the open end and tapping it down with a hammer.
Step 10: Drill a Nozzle
Once the motors are packed, use a drill to drill a nozzle down the center of the motor. It should be slightly smaller than the hole in the motor casing nozzle and about 2/3-3/4 the depth of your fuel.
Step 11: Blast Off
You are now finished. Put your motor into an appropriate size rocket, install an igniter, and fire it off.