Picture of Making Rocket Fuel With Kitchen Chemistry!
Today we're doing some kitchen chemistry using common household items.  This is the type of cooking that gets me excited, because I'm experimenting with recipes for solid-state rocket fuel.
Remove these adsRemove these ads by Signing Up

Step 1: Watch The Video!

WARNING: This project should not be attempted without adult supervision and adequate training. Misuse, or careless use, of tools or projects may result in serious injury, death, and/or permanent damage to equipment and property.  Ignition of an incendiary or explosive material may not be legal in your area.  Use of this content is at your own risk.

Step 2: KNO3 and Sugar

Picture of KNO3 and Sugar
For this project, I wanted to use some kitchen chemistry and a few common household items to test out a few different methods for making rocket fuel.  This type of rocket fuel is commonly referred to as "R-Candy"

The main components of this composition are a brand of stump remover, which is 100% potassium nitrate (KNO3), and plain white table sugar.

In addition, I tried using different amounts of corn syrup and homemade rust powder.  The rust was made by mixing steel wool (like these scrubbing pads) and vinegar, then letting it rust out over the course of 1-2 weeks.

Step 3: Mix Intimately and Caramelize

Picture of Mix Intimately and Caramelize
When mixed together in ratios of 60% KNO3/40% Sugar by weight, and placed on medium heat, they melt into a creamy brown liquid. This is because the sugar caramelizes and absorbs the KNO3. The smell is similar to that of making candy, and that's why this is sometimes referred to as "Rocket Candy" or "R-Candy".

The mixture is volatile, and will violently ignite if brought in contact with a flame, so extreme caution needs to be used at this point.

When it's runny enough, it can be poured into a casing to cool down and solidify. I'm using these Mega-Block LEGOs. Watch out, it's hot!
1-40 of 157Next »

hey love all your videos :D is ammonium persulphate a suitable substitute for KNO3? It a little easier for me to get


JohnM9421 days ago

Mix everything by weight. 30% sugar, 60%potassium nitrate and 10% sulfur for the best rocket fuel. Melt slowly and pour into tube. Nozzle should be 60 degrees entering side (converging) and 30 degrees leaving (diverging) and the hole should be 1/3 the dia. of the motor tube. Tubing should be seamless steel. Nozzle..cold rolled. Bulkhead...cold rolled. To give it an intitial pulse put a rod up through the nozzle about 1/3 the length of the motor. Pour the liquid propellant over this rod. Pull the rod out when cooled.

ryckmans_t2 years ago
Sorry, but isn't the point of an Instructable to give instructions? This entry would be much more interesting if actual data was provided, e.g. at least state the units of ratio ("weight" for KNO3/sugar only appeared in the comments, nothing for the rust).
The King of Random (author)  ryckmans_t2 years ago
If you read the whole instructable you would see that KNO3, Sugar and "weight" were actually all in the instructable, so I'm confused by your complaint.

For your convenience I added 1% to the statement about the rust.
when you say weight, would that be like if you used so many cups of KNO3 you would have to use so many cups of sugar?
That would be volume. Weight means how much they weigh on a scale. Eg. 1 lb of bricks vs 1 lb of feathers.

When mixing components always use weight...not volumn. So if you have one pound of sugar you need two pounds of potassium nitrate and 1.6 oz of sulfur.

oh so if you had 1 pound of sugar you would need so many pounds of kno3?
seriously? they give you percentages. 40% sugar, 60% potassium nitrate. (stated in the video, and on page three) i dont mean to be rude but how hard is it to figure out four parts sugar to six parts stump remover? but, if you must, 1 lbs of sugar, equaling 40% of the weight, means the total weight is 2.5 lbs. which means 60% of the weight, stump remover, is 1.5 lbs.

just take the percentage of how much you are mixing. For example, if you are making 2 cups of r-candy, what is 40% of 2? 60% of 2?

عدي غالب

عدي غالب


Umm, he literally weighed it right in front of you. He used a kitchen scale and weighed it in grams. The percentage number was based on how many grams of each product were in each mix.

JohnM9421 days ago
Bubdob6423 days ago
Is it possible to produve this rocket fuel on a larger scale? (E.g. about 10 pounds of it fuel) to blast a rocket into the sky?
Corinbw3 months ago

along with the rust being added to the mixture, you could also add powdered aluminum so that you get the a thermite reaction that happens at the same time as the other one. This will probably burn hotter, but it might not burn faster, you should give that a try though

TristanM5 Corinbw2 months ago

will do man

TristanM52 months ago

omg it works i did it

Nemweb3 months ago

What about using the KNO3 itself? Pure KNO3?

VipinY3 months ago

what if i dont have KmNO4

could i use an electric model rocket starter to start it rather than a blowtorch?

TomT64 months ago

could this be used as an actual rocket boster on a real life scale?

TomT64 months ago

could this be used as an actual rocket boster on a real life scale?

Hey instead of a electric burner , can i caramelize the mixture over a gas flame in saucepan ? Is it dangerous or will it do ?

yes very dangerous to use gas flame.

aesquivel4 months ago

Another (dumb) question: KNO3 by itself is not flammable (as far as I know) and sugar isn't either so why are they flammable only by mixing them? do they react chemically even if they are not diluted? (sorry, I didn't pay attention in HS chemistry)

Sugar is flammable, and acts as the fuel. The KNO3 acts as the oxidizer and provides the oxygen needed to combust quickly.

aesquivel4 months ago

I saw your other video where you use 3/4" Schedule 40 PVC pipe, would a bigger pipe also work and may be able to sustain a heavier payload or 3/4 is the best option?

how long does it burn? I'd like to put it on an airplane. literary every thing I find needs to be put on a model aircraft.

Depends on your mixture. Make it and time how long it burns.

joshadkisson made it!5 months ago
I made a sugar rocket, but I didn't have to carmelize my fuel, I simply used a 1" pvc pipe, powdered kitty litter for the nozzle, and a 60%/40% mixture of KNO3/powdered sugar. I even mixed in magnesium shavings for spectacular flare!

good indestructible for fuel testing though, I like the use of Legos.
ajp45 months ago

Do you need to wear a mask when caramelizing them?

shadowop5557 months ago

that is AWESOME!!!

does this make toxic gas when its carmalised
Fission Chips8 months ago

Upon making this with a friend, we were both ecstatic to see it shoot high up into the air! Great Instructable. I love your videos!

SebiA8 months ago

Hey Grant! I love all your experiments! Keep impressing me please!

SebiA8 months ago

Hey Grant! I love all your experiments! Keep impressing me please!

huddleto10 months ago

I have about 30 cedar tree stumps to get rid of. I tried salt peter and sugar but it just blew the stick I used to plug hole with about 20 feet in the air. Any suggestions?

patbking1 year ago

is there a substitute for KNO3


1-40 of 157Next »