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.

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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!

Step 4: Variations

Picture of Variations
I tried some more batches with other ingredients added, like water, corn syrup and even tested a little home made rust powder (Iron Oxide - about 1%).

All the fuels burned a little differently, but overall I was most impressed with the batches using the homemade rust.

To see the burn tests, you can watch the video here.

Step 5: The Best Batch

Picture of The Best Batch
I made another batch and packed it into a homemade rocket motor casing that had a nozzle made from kitty litter. I was impressed to see it actually worked! I think this rocket shot up a couple thousand feet.

If you haven't see the video yet, it's not too late.  Watch it here!

If you like this project perhaps you'll like some of my others. Check them out at www.thekingofrandom.com
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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.
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.
Actually the atomic weight of potassium nitrate Is much light than a sugar compound therefore one part KNO3 is not equal to one part Sugar. This is why we use weight as a unit of measurement when working with chemicals.

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?

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.

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.

Biggerdog2 years ago
I'm pretty sure the burn rate increases because oxygen is released from the iron oxide when it is heated and the increased oxygen increases the burn rate of the other ingredients. No additional exhaust gas is generated, but the created gas is released more rapidly, increasing the thrust. Since the thrust is proportional to the mass of the gas times the velocity squared, increasing the velocity is much more effective than increasing the mass. BTW, the iron oxideand aluminum mix is called Thermite, not termite. The burning mixture consumes oxygen, so does not give off gas. Iron powder may not contain any oxide, so must be oxidized. Perhaps soaking it in water and letting the water evaporate slowly will do it. I've also used potassium perchlorate as an oxidizer. This is very effective, but too much results in an explosion rather than a controlled gas release.
Yes the burn rate would increase due to the higher levels of oxygen due to the necessary ingredients to create thrust ( fuel + oxygen + chain reaction) also the more oxygen you have in the compound the higher surface area you will have for combustion.
Can u tell me how to make rocket fuel WITHOUT KNO3 please

simple, all you need is LOX ( liquid oxygen) and LH2 (liquid hydrogen). but you dont have those, so the answer to your question is "no" unless you have LOX and LH2. (this is how NASA makes the base of their rocket fuel. the also ad a certain mixture but i am unsure of what it is.) ;)

They would add a hydride with a strong oxygen compound like bi- or tri- oxygen.
its pretty easy to get... look in garden center or online
lharket1 year ago
Which one had the fastest burn-rate, was it 13syrup 30water 59KNO 30sugar?
The mixture that burns the fastest would have the least fuel and a good catalyst (iron oxide - rust) therefore the 60/40 +1g rust would have the fastest burn rate.
-JMS-1 year ago

Is it possible for u to make a rocket fuel without KNO3? Use I g only kitchen items?

Step 1: Get Hydrogen Peroxide. Step 2: Distill the Hydrogen Peroxide. Step 3: Add silver dust to start the combustion. Note: this is liquid fuel and it will be harder to use but a lot more efficient

Uhmm... no. Never distill hydrogen peroxide as it will readily combust violently with anything it comes into contact with. Unless of course you are an experienced chemist.
huddleto11 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?

Use about a quarter pound mixture (114 grams) and add charcoal (about 20 grams will do) but this time do not plug the hole as that creates a small deflagration
ajp46 months ago

Do you need to wear a mask when caramelizing them?

AstroFire ajp415 days ago
Not unless you are melting the KNO3 first in which nitrogen dioxide would be a byproduct thus requiring a mask but since the sugar is only being melted in this instructable no mask is needed.
aesquivel5 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?

I made a rocket propelled Longboard using this thought process: large inside diameter tubes (carbon steel) with a higher level of oxidation to provide a lot more thrust and then I also used a different kind of sugar called xylitol which has a different bond that is more suitable for larger engine bodies. this sugar is used in engines that are optimal for high altitude propulsion or heavy payload propulsion because it will not crack under pressure.
aesquivel5 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)

No problem, the reason that this compound is a strong candidate for a propellant is because the oxygen from KNO3 transfers over to the sugar to create carbon oxides and nitrogen oxides which act as the positive thrust which in turn push the rocket off the ground and then the heat created as a byproduct of the initial reaction starts a chain reaction within the rest of the compound.

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

Bubdob641 month 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?
Yes although adding a higher oxidizing molecule like ammonium perchlorate or potassium permanganate would allow for a stronger overall thrust due to the heat created as as byproduct of the oxidizer reacting with the fuel.

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


you can try but I would think that it would either not work at all or the mixture would smoke out as the persulphate bond is too stable to cause a volatile chain reaction therefore we use nitrogen bonds because they are extremely unstable and are perfect for causing volatile chain reactions.
Nemweb4 months ago

What about using the KNO3 itself? Pure KNO3?

No the KNO3 would not work by itself as it is an oxidizer and to have a successful bipropellant you would need a fuel ie. (sugar)
JohnM941 month 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.

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