Picture of How to make rocket candy
Rcandy (Rocket candy) is a Medium-Fast burning Solid Rocket Fuel and propellant that has many uses in fireworks and amateur rocketry and is the much more powerful "Brother" to the smoke bomb burning over twice the smoke with the same amounts.
In this instructable I will explain the materials, Processes and safety precautions to be taken in the production of Rcandy.
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Step 1: Safety precautions

Picture of Safety precautions
Rcandy uses a Recrystalisation process making it much more potent.
First a few safety tips:

- During the whole process have a fire extinguisher near you and/or a fire blanket,
- Wear full face protection During cooking and ignition because things could get ugly:


- Use an electric Stove and fan forced oven.

If you are under 18 or if is illegal for you to complete this process Do Not continue or Continue at your own risk, I am not liable For ANYTHING
Keep in mind Rcandy is classified as an incendiary.

Step 2: Materials and chemicals

Picture of Materials and chemicals
Gathering the chemicals especially Potassium Nitrate is difficult and to get these from a chemical supplier you need to be 18 years old (possibly 16 in America) but its easy to get at other sources:

Potassium Nitrate / Saltpeter: Chemical compound KNO3
Stump remover (95%-99%)
Chemical suppliers (Perth= Sigma chemicals or Daly)
Industrial chemical suppliers
Fertilizer stores (>85%)
MSDS: http://www.jtbaker.com/msds/englishhtml/P5950.htm
The LD50 is about 300 grams

Sugar: Chemical Compound Sucrose (C12H22O11)
From supermarkets
Icing sugar is best otherwise: White sugar
Fairly universal and harmless so no MSDS is needed

Iron (III) Oxide: Chemical Compound Fe2O3
Oxide colouring "Brick" Red (99%<)
Bunnings or any other good hardware store
MSDS: http://msds.chem.ox.ac.uk/IR/iron_III_oxide.html
Stains like HELL

To buy I suggest about 1Kg of KNO3 at a time the smallest amount of Iron Oxide (for me about 250g) and another kilo of Sugar.

Other materials or tools will be refered to during the instructable.

Step 3: Mixing the ingredients

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The KNO3 and sugar doesn't have to be in powder form because it is going to be dissolved in solution (Save some cash and buy coarse grain) but the Iron Oxide being insoluble has to be crushed finely into powder before being used.

Mix in a cooking pot:
64g of KNO3
35g of Sucrose (Icing Sugar)
1g Fe2O3 (Powdered)
And add 30-40ml of hot water
Tip: don't make any more than 100g at a time because if there is an accidental ignition the danger is steeply increased!
Tip: If you do decide to make more or less size batches use about the same amount of water as the sugar.
This has a burn rate (for a 5mm thick strand) of 0.41 cm/sec

-As far as I know the mixture is shock and friction insensitive but high temperatures (145C<) will set it off
(DO NOT quote me on that!)
-If you are a lazy bugger you can just burn this as a powder (without the water) but it won't be as impressive.

If you cannot locate iron oxide use this and continue on.
65g KNO3
35g Sucrose (Icing Sugar)
40ml Hot Water
This has a burn rate (for a 5mm thick strand) of less than 0.41 cm/sec

Or if you want to try James Yawn's formula mix
30g KNO3
15g Sucrose (Icing Sugar)
7ml Karo syrup
30ml Hot water
Without Iron Oxide burn rate (for a 5mm thick strand) 0.211 cm/sec
With Iron Oxide burn rate (for a 5mm thick strand) 0.362 cm/sec

Step 4: Cooking Process

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Put the pot onto a stove and set it to about 150 Celsius while stirring constantly to dissolve the KNO3 and Sugar.
Before the "Crystal Mush" stage Do not use gloves! It may soak up and Ignite, case in point fusepaper...
Once all the solids have dissolved you can turn the heat up a bit.

Tip: if the solution starts bubbling up a lot simply turn down the heat and be patient.

Eventually there will be a red slop and once it starts having the texture more viscous than water this as James Yawn says the "Crystal Mush" stage now turn down the heat to 125 Celsius and put Gloves on.
Once you have passed this stage make sure you mix and stir the propellant a lot because it reduces bubbles of air making it more durable once done.
When it starts looking a bit like putty turn the heat down to 107 Celsius and continue to cook, if you still hear sizzling then there is still water in it.
Once the sizzling has stopped you can take out a small piece the size of a pea and roll it with your fingers.

Tip: Make sure that the Rcandy is covered by something while you are off doing other things so that if it does ignite there will be less damage.

If it feels sticky that's the moisture in it so continue cooking, if its easily roll-able and not sticky mash it flat and let it cool. Once cool bend it and see if it snaps if it bends then keep cooking the rest of it and do another test in a few minutes if it snaps and is brittle then it is ready for moulding and the Rcandy has finished cooking.
-Remember that the propellant is very Hygroscopic so it likes to suck up water from the air, I did a rocket that was supposed to have a burn time of 0.2 seconds and it went for 15 so keep it dry.

Step 5: Flash-Candy

Picture of Flash-Candy
since I have discovered flash candy I have been very worried about its use as a low explosive, and recent test results show that it is has possibly over twice the same power as gunpowder, please do not use in a small or confined space or rapid deflagration will occurr causing explosion!

Flash-candy is a name I gave Rcandy that has been powdered finely and dehydrated which acts similarly to gunpowder and can be molded cold.
Heat oven to 100C - 140C
Place already recrystalised Rcandy into a food processor or Whizzer and give it hell for at least a minute, once its a fine powder have a feel with a spoon.
Unless you're really good at recrystalisation there should be some residual water and it will be squishy and will not flow like dry sand.
So leave to heat in oven for at least 10 minutes and take some out for a try.
Use a fuse! I had the misfortune of finding out what it's capable of so be careful:)

Ignition techniques
I Suggest electric ignition for anything big 50g< but otherwise use a fuse.
Don't use matches or Lighters
Whatever you have seen on youtube this stuff burns faster with a very hot flame!

I would like to acknowledge James Yawn for not just his inspiration but his process in which this instructable is a hybrid.

I have recently added:
An instructable on the common firework the Roman candle
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vignesh12305 years ago
What if you have a gas stove and cant set the temperature? Is there different instructions?
Tombini (author)  vignesh12305 years ago
I would not recommend using a gas stove since this is a form of rocket fuel which is highly flammable and any chance of ignition is a severe danger. If you really wanted to use a gas stove you could perhaps use a oil bath but still I wouldn't reccomend it.
Does anyone know how to make rocket motor casings? I have read many comments that hint that I can make them using stiff paper but I have not found a detailed description of how to make them. I also have had trouble finding ways to make rocket nozzles.
Tombini (author)  148wmcquiston5 years ago
Look at my instructable for making roman candles, it shows a procedure that produces good motor tubing. Alternatively you could just buy some tube.
You can also flick a tadbit of water onto the mixture to see if there is any water left. If it immediatley turns to steam, you know that the mixture is above boiling point, and it is not bubbling, therefore there is no water.
Tombini (author)  I_am_Canadian6 years ago
That would seem logical
I have done it, seems to work.
tudgeanator6 years ago
What would you suggest i use as a rocket fuel: Should i use BP in the traditional 'rammed' method, or this r-candy? Which fuel with make the same sized rocket fly highest?
Tombini (author)  tudgeanator6 years ago
There are plenty of pros and cons for Rcandy; Rcandy Pros -small amount of slag -easily made -relatively safe Rcandy Cons -Not as high a specific impulse than BP (I think) -Fractures in the grain are more prominant -Hygroscopic and to answer your question, a BP rocket would fly higher but I think it wouldn't be worth the trouble
Thanks alot, im gonna give rcandy a try and see the difference in performance for myself. Oh,sorry for the slow reply, i thought i allready had.
lil jon1686 years ago
you dont have to have iron oxide
Tombini (author)  lil jon1686 years ago
Yes the Iron Oxide is an optional catalyst that increases the burn rate by 50% That said, Ive never tried it without it so the results will be variable
Question, I tried to change this up by dissolving the salt peter in 91% rubbing alcohol then mixing it with molten sugar, the first time I did this The salt peter was in little balls about one millimeter in diameter and I mixed the sugar and salt peter first then added alcohol in small bits, this dissolved the saltpeter(I saw the balls disappear), however when I heated the alcohol to boiling using a hot water bath the saltpeter did not really dissolve in the the alcohol very much, why was that.?
Tombini (author)  optimistcynic6 years ago
The properties of different solvents can vary, Ethanol (CH3CH2OH) which I think is the main ingredient in rubbing alchohol. This can dissolve some solids and not others, depending on their polarity ect... KNO3 and sucrose dissolve very well in water (all nitrates dissolve in water) But CuCl dissolves in Ethanol and NaCl doesn't, so I have no idea :( btw the little pellets are known as "prills"
I find it quite interesting that the stoichiometry in your 'ible is explained much better than my chemistry teacher might have put it.
Tombini (author)  guitarman63mm6 years ago
Thanx man, my chem teacher is nice but not so good either. At the moment we are learning about atomic structure and covalent bonding :) How condescending...
if I don't add any iron to the mixture will I get drastically different results
Tombini (author)  coolpizzadude6 years ago
The reaction rate will be eccentialy divided by 2.5 If you do It just means rockets ect will need to be designed differently to incorporate the slower burn rate I suppose it would work with the roman candles, but ive never used it :P
killa6966 years ago
Looks good. Does the iron also make it burn a certain color?
Tombini (author)  killa6966 years ago
No, the Iron oxide acts as a catalyst only
Have you tried alcohol instead of sugar. I tried a one to one ratio of sugar to saltpeter melted the sugar and added alcohol to dissolve the saltpeter. the alcohol was boiling but did the job and that way I could form it while it was still wet and not have to what for it to dry completely. Granted the first time it caught fire but the second time it worked great.
Tombini (author)  optimistcynic7 years ago
Yes I have been pondering using 50% Methalated spirits 50% water for cooking because it would evapourate much easier... But the flammability danger is greatly increased because of the ethanol, and the water method works fine for me. As a fuel I strongly suggest against it, Ethanol Is a liquid and it will make a composition similar to ANFO! P.S. August 2 my BIRTHDAY!
831 Tombini6 years ago
cool g im new can u send me 1 of ur eseys resipes in ml so i gan get it good
Tombini (author)  8316 years ago
This is as simple as I'm going to make it, if you don't understand it study the concepts expressed and learn some chemistry. This page is not about making bombs its about science.
When I did it I was using 91% rubbing alcohol. And although the alcohol itself is flammable the boiling of the alcohol kept the reaction under the flash point. the first time it caught fire when we were trying to boil the last bit of it off. In short as long as you keep it in a well ventilated room so the the vapors don't catch it doesn't seem to spontaneously combusted when using alcohol. P.S. A. what is ANFO and how ethanol make it like the it, and B. does a fire extinguisher work on this type of fire since it has it's own oxygen supply. I know water works but I figured that was because it lowerd the temp of the fire.
Tombini (author)  optimistcynic6 years ago
ANFO stands for Ammonium Nitrate Fuel Oil and is a mix of 95% NH4NO3 and 5% diesel fuel, it has had much media attention due to its use in terrorism...
And the reason it could act like ANFO is because it is in the end fairly similar (a solid oxidiser and liquid fuel)
I don't actualy know!
Water and CO2 definately work, dry powder should as well.
I think someone misunderstood someone. I was not sugesting using the alchol as the fuel. I was sugesting using it to combine the sugare and salt peter. I usualy boil of most of the alchol. but this way if I don't boil it all off the disoving agent will help not hinder the reaction.
Tombini (author)  optimistcynic6 years ago
Yeah I guess so... Its just if it does catch fire during the process its very dangerous
feswee6 years ago
how come you don't have this on pdf??
you can also try making golden powder if you risk using the oven for this method. 60 grams kno3 to 40 grams ascorbic acid (vitamin c). search youtube :)
Tombini (author)  Pyrochemistry6 years ago
That looks very similar to well refine flash candy, and it seems easier to make. I wonder if anyone has recrystalised it? It would be very dangerous then What on average is its sensitivity? (in joules)
deadpyro6 years ago
I can't find Kno3 any where!!!!!!!!!11
Tombini (author)  deadpyro6 years ago
Where on the planet are you located?
I live in the U.S.A. Oh, if you wondered i changed my name.Where do you get your Kno3?
Tombini (author)  bylerfamily6 years ago
Have a read of the instructable a bit closer, It explains everything...
deadpyro6 years ago
Did you get this idea from James Yawn?
Tombini (author)  deadpyro6 years ago
Read it then comment; "I would like to acknowledge James Yawn for not just his inspiration but his process in which this instructable is a hybrid."
deadpyro6 years ago
I'm sure that flash candy does not quite make a fire ball like that.
Tombini (author)  deadpyro6 years ago
No, thats an atomic bomb.
But flash candy burns similar to gunpowder just 5x the smoke, so 100g = 2 meter flame and a 4 meter diameter mushroom cloud.
Tombini (author) 7 years ago
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