Rocket Propellant (Candy)
From PyroGuide
Candy propellant is popular in amateur experimental rocketry, mainly due to the availability of the chemicals and ease of use. It is usually prepared by melting potassium nitrate and sugar together, but this is obviously a somewhat dangerous operation. Dry mixing is possible and much safer but produces lower quality propellant. Because Candy propellant is a very easy to make propellant it is listed in the Beginners’ pages.
The ratio of potassium nitrate to sugar may be varied to alter the properties of the propellant, but the following formulation is most commonly employed:
Composition
| Potassium nitrate | 65 |
| Sugar | 35 |
The composition produces a relatively large amount of smoke due to its similarity to smoke mix. You can increase the burn rate of this mixture by adding 1% Iron oxide (red) to the mixture. A noted product of this combustion reaction is potassium oxide which absorbs water and turns into very caustic potassium hydroxide which may react vigorously with some chemicals and isn't good to get on skin.
Smoke
A similar mixture can be made simply for making smoke mix.
Powder form
There is a way to create candy propellant that evolves wet mixing. It creates powdered candy propellant that burns almost like commercial black powder and isn't hydroscopic like the molten sugar method.
Wet Mixing Method
This method has a faster burn to it, but requires more work. Full details can be found at Jamesyawn.com, but a chart with the correct mixture is provided below:
Composition
| Potassium nitrate | 30 |
| Sugar | 30 |
| Water | 25 |
| Corn Syrup | 10 |
| Iron oxide (red) | 5 |
Simply mix all ingredients together in a saucepan and bring to a boil on an outdoor heating element. Keep the mixture at a boil until all of the water has evaporated. When the mixture is the consistency of peanut butter, remove pot from heat. Spread mixture out onto cookie sheet and let dry in the sun for several hours. Your fuel should now be brittle and hard. Grind up by placing all material in a plastic bag and breaking it up with a hammer.