Sciencemadness Discussion Board

First Rocket Candy attempt

Oppenheimer - 26-11-2010 at 06:42

Ok so yesterday I tried to make my first batch of rocket candy using

60g stump remover (KNO3 I hope--didn't list materials)
30g sugar
14g sugar syrup

I'm going to try and find some iron oxide today at a pigment arts and crafts store.

I think my problem was that I didn't let it cook long enough, I had it to there point where it was a very thick paste, and rolled it into a cylinder for a burn test, but it was till a little bit sticky, and baaaarely snapped when it was cool.

I am going to try again and cook it a bit longer to drive off more water.

My only question is, if the stump remover doesn't list ingridients, how can I be sure its KNO3 or NaNO3 and not NH4NO3?

While cooking I got a whiff of some of the fumes and they immediately made my lungs close up and I had to back away.

It sort of smelled like ammonia...but I am wondering if it was something dissolving in the water in my nostrils/lungs to give it an acidic burning smell.

Ammonium nitrate decomposes into N2 O2 + maybe it isn't ammonia I"m smelling?

Any ideas?

Joauml - 26-11-2010 at 07:09

Stump remover can be many things. Try mixing it with sugar (2 stump : 1 sugar) and try to burn it, if it's NH4NO3 it will barely burn, if it's NaNO3 it will burn with a very yellow flame and if it's KNO3, it will burn with a faint purple color or little yellow. It also can be metabisulfite or even chlorate.

Oppenheimer - 26-11-2010 at 09:34

Thanks for the reply. I found a great video by Nurdrage on youtube about testing stump remover to find out what it is. I've mixed dry powder and sugar together, and a match wont light it. I don't have a butane torch to try it at a higher temperature though.

After i read it could be a metabisulfite in your post, I looked that up, and found that can give off sulfur dioxide, which is a pungeant harsh gas (Fits the bill of what I've been smelling) which when mixed with water can produce sulfurous acid (which would explain the burning smell in my nose/lungs).

I emailed the company to try and find out what it is...but now I"m leaning towards sodium metabisulfate. THanks for the help

entropy51 - 26-11-2010 at 13:37

If you just got crazy and posted the name of the stump remover someone here could probably tell you what it is.

The Bonide brand is metabisulfite and if you add a little vinegar to about a gram you will smell SO2.

Ozone - 26-11-2010 at 13:52

Heating sugar with a trace of acid will ultimately give formic and levulinic acids. These will react will metabisulfite in the same way as acetic acid (vinegar).


Oppenheimer - 26-11-2010 at 16:33

haha yes entropy51, in all the critical thinking I did, I completely forgot the most simple approach. It is Bonide, so it was sulfur dioxide I was smelling, and it is also why the rocket candy never worked. Case solved. Thanks

Bismuth - 28-11-2010 at 23:29

I know... I know...

We go through this thousands of times. But be bloody careful about making r-candy. A LOT of accidents happen when cooking it and they often result in 2nd degree burns. If I had to put money on it, it's one of the most common accidents when dealing with 'pyrotechnics'.

Recently someone on a forum I frequent had an accident making it and his burns look nasty. I also believe iron oxide lowers the activation energy of the mixture. The quantity you're making at a time is enough to do a fair bit of damage. But enough of that... I felt obliged to just throw that out there due to recent incidents. Back to the Science.

It might be worth recrystallizing the potassium nitrate when you acquire a source (if you plan to use stump remover) before you use it as some blends can be rather contaminated. It's not much effort to do anyway. Happy experimenting.

ScienceSquirrel - 29-11-2010 at 03:21

A version of rocket candy was known as Paxo, after a proprietory brand of stuffing mixture available in the UK. The stuff was made by the Provisional IRA for use in letter bombs, etc, it was notoriously unstable.
Trying to make explosives by mixing unknown materials together is madness.

quicksilver - 29-11-2010 at 08:11

Quote: Originally posted by ScienceSquirrel  

Trying to make explosives by mixing unknown materials together is madness.

Don't waste your time. This will be closed shortly: it's lack of science is obvious, it's danger - overwhelming. Things will get back to normal in a bit here.

ScienceSquirrel - 29-11-2010 at 14:14

Sadly I keep on saying it but too many people ignore it.
Chemists should learn their trade with safe chemicals and reactions before moving on to things that are more challenging.
There is a significant chance that if your first organic synthesis is Triacetone triperoxide, ( TATP ), it will be your last!

Oppenheimer - 29-11-2010 at 14:24

Well thank you for the concern, but I make sure to wear proper safety equipment and work in small quantities before scaling up. I was under the impression rocket candy mixes of potassium nitrate and sugar were QUITE stable, as I've seen numerous videos of people making it in their kitchen or outside with no apparent problems.

What accidents arise that have given people burns? Would gloves have prevented the problem? (Thick gloves not nitrile or latex)

I bet some people have used their open flame stove tops for it as well, when an electric oven would be more suited to the task.

Also, I'm not following how "Trying to make explosives by mixing unknown materials together is madness."

My intention was never to make an explosive.

I'm a senior undergrad in chemistry, so I do have appreciation for safety and potential hazards, but I do not see this as an extremely challenging or dangerous experiment.

Also thanks for the heads up about re-crystalization, although at this point with united nuclear selling kno3 for $3 I might just go that route.

ScienceSquirrel - 29-11-2010 at 16:45

Your stump killer could have been based on sodium chlorate!
Sugar, sodium chlorate and a few odds and sods on a hundred gram scale could turn you into a mess of bits of flesh and bone that will never be recognisable by your mum and will require shovelling in to a plastic bag in a closed coffin :(
Rocket fuels are explosives, they are just not explosive enough to blow you apart out right!

ScienceSquirrel - 29-11-2010 at 17:00

Quote: Originally posted by Oppenheimer  
Ok so yesterday I tried to make my first batch of rocket candy using

60g stump remover (KNO3 I hope--didn't list materials)
30g sugar
14g sugar syrup

If that had been sodium chlorate it could have gone off with the power of a quarter of a stick of dynamite!

Oppenheimer - 29-11-2010 at 17:12

This is true, it was quite stupid to start with 60g of an unknown oxidizer, it's just that all the reading I've done and videos I've watched, I've seen people use far more then that, and the product appears to be a stable thick paste.

It's strange to me picturing a mixture of compounds actually EXPLODING with enough force in an open pan to actually cause damage.

Perhaps next time I will use only a few grams (of a known oxidizer) and see if it works.

ScienceSquirrel - 29-11-2010 at 17:30

Quote: Originally posted by Oppenheimer  
This is true, it was quite stupid to start with 60g of an unknown oxidizer, it's just that all the reading I've done and videos I've watched, I've seen people use far more then that, and the product appears to be a stable thick paste.

It's strange to me picturing a mixture of compounds actually EXPLODING with enough force in an open pan to actually cause damage.

Perhaps next time I will use only a few grams (of a known oxidizer) and see if it works.

There are plenty of things that will explode in an open pan and create significant damage on a gram scale.
Try silver or copper acetylide, lead azide, iron picrate.
Or stick a gram of them in a test tube and shake in front of your eyes, instant white stick for life! :-(

Oppenheimer - 29-11-2010 at 17:42

So has anyone tried the KNO3 Sugar r-candy mix and come out unscathed?

ScienceSquirrel - 29-11-2010 at 18:37

If you start with known ingredients and follow a good procedure using appropriate care you may be OK.
But it really is not my first experiment!
The whole idea of practical chemistry is that the student gains experience during their career so they can handle more challenging substances safely.
Even the best chemists make mistakes but years of experience do provide some protection when handling the truly deadly like dimethyl mercury.

Oppenheimer - 29-11-2010 at 19:04

I have no interest in dimethy mercury or copper acetylide or any other deflegrating/explosive agents, only rocket fuel mix. What experiments would you do as you rfirst experiment then?

Ozone - 29-11-2010 at 19:38

Rocket candy is FINE (many of us made it when we were kids)! Just know what the hell you are putting in the pan (and how much). And, do it outside, or with appropriate ventillation and fire extinguishing/safety equipment/knowledge.

Your FAILURE to do ALL of these things could have led to catastrophic consequences (at the very least, being gassed with SO2 is unpleasant).

Are you functionally unable to realize that we would like for you learn how to experiment safely (or do you counter all advice defensively?) The first step is to listen to those who are trying to help. The second is to do some research. A quick search on YouTube, for example, has several videos of successful preparation...and several videos, perhaps more useful, of failures and accidents. See especially the deflagration which occured during a preparation in a garage ( would have been bad news in a kitchen).

Edited for an admittedly ambiguous statement I made last night. Apologies for that.



[Edited on 30-11-2010 by Ozone]

[Edited on 30-11-2010 by Ozone]

Oppenheimer - 29-11-2010 at 20:08


Are you functionally unable to figure that this is the realization that the others would like for you to have?! Sheesh,

I don't know what that means. Does that mean other people want me to blowup?

Ozone - 29-11-2010 at 21:32

Edit: Alright. I'll retract that. It wasn't constructive.

Am I the only one who is unusually sensitive after the recent rash of frustrating posts (especially with energetics)?

[Edited on 30-11-2010 by Ozone]

psychokinetic - 29-11-2010 at 22:54

Sheesh O3. I had to read it a few times to make sure, too. o.o

No Oppenheimer, we want you to be safe, and not stupid :)

Aside from the fact you stuck unknowns in, you seem to at least think about what you are doing. We've had a small rash of morons in this here department that don't understand that safety and science go hand in hand.

Even when you're going to be unsafe, do it safely ;)

Microtek - 30-11-2010 at 06:34

Candy propellant is quite safe (as energetics go). If you haven't already, take a look at James Yawn's site about "recrystallised" candy propellant. When you mix the ingredients wet, you avoid a lot of the dangers of conventional pyrotechnics preparation. Also, when you only heat the mixture to ca. 110 C to drive off most of the water instead of melting the mixture you avoid another major risk.

ScienceSquirrel - 30-11-2010 at 07:44

Potassium nitrate and sugar is several orders of magnitude safer than potassium or sodium chlorate and sugar or worse sulphur.
Making energetic materials, be they explosives or propellants, requires exact knowledge of what you have and a good guide to their preparation.
You want to start with a known good sample of potassium nitrate and make about 5 -10g on your first go following the instructions on James Yawn's site exactly.
I would use a thermometer and regulate the temperature as closely as possible.
Remember at all times, you are making rocket fuel, NOT play dough! :P

Rosco Bodine - 3-12-2010 at 03:54

This thread starts out with an ill conceived notion that a science experiment is mixing unidentified materials and then "cooking" the mixture at an unspecified temperature, following no detailed or monitored procedure, with the goal in mind of making rocket propellant. This isn't really a valid science experiment. It isn't logical or safe to handle pyrotechnic compositions in a way that is foolish.
A kitchen is not a safe or proper place for making rocket fuel.
(An electric oven is not the proper tool either)

Edit: Oppenheimer sent me a U2U clarifying that the
procedure described in the original post was done outdoors
using a thermostatically controlled hotplate. Such details
should have been included in the first post describing what was being done. I'll reopen this thread and see if any useful links or discussion is added. There are several rocketry specific pages which have extensive information.

Here is one of them
sugar rocketry links page

[Edited on 4-12-2010 by Rosco Bodine]

gregkdc - 22-1-2011 at 14:28

I was just wondering if you guys have done any more experiments with rocket candy?

If you want to know what your stump remover contains the simplest way of finding out is by looking up the MSDS on line.
I have done this multiple times to find various chemicals locally. Rocket candy is about as safe as you can get with an energetic mixture (as long as you do in fact have rocket candy). I have been making it since the early nineties and I have never had anything close to an accident. I have never seen it ignite from friction or impact, not saying that it can't, but I have really tried to get it to go off with the friction and hammer test. I also destroyed the thermostats in an electric frying pan so it wouldn't stop heating and cooked up a batch and let it keep heating just so see what would happen. All it did was brown never ignited. I did see a guy have a close call, he was making recrystallized rocket candy and let some of the propellant boil over and run into the plug of his skillet. When the propellant got into the plug it ignited but it didn't ignite the rest of the propellant.
That being said don’t get over confident with rocket candy. It has more power than black powder and just a teaspoon of black powder in a gun has enough power to kill a large animal like a bison. I hope that putts things into perspective.
The most common problem people have with rocket candy is not when they are making it which is probably safer than pouring sulfuric acid or lye form a beaker. The big problem with rocket candy is when they go from making a batch of propellant to actually wanting to make a rocket motor. It can be vary hard for the beginner to control the surface area of the propellant, or to even know what to look for when making propellant grains. Next they take this propellant with an unknown surface area and ignite it in a casing not knowing that they just made a pipe bomb.

So most guys start at the other extreme and deliberately make motors that are under pressured, while this is a little safer there are dangers involved with this approach if you rush into things. Many guys once they get a working motor are so excited they move forward with a working rocket before they have characterized their motors. Invariable the motor is underpowered and their rocket turns into a land shark that could cause physical harm or start fires. So you can see as with any endeavor it may be more complicated than you think. Best of luck if you do decide to continue.

Nothing like rocket stuff...

albqbrian - 27-6-2011 at 07:10

I have to say, one can learn a whole lot of great chemistry and physics via rocketry. And making your own propellant and motors? Even more. As with any experimental chemistry it requires a modicum of caution and common sense. You've heard enough particulars.

Personally I think Ammonium Perchlorate Composite Propellant (APCP) is safer, but that is opinion. Plus you do require more, and more expensive; chems. So Candy propellant is a logical 1st try.

If you are doing Candy, read Richard Nakaa's stuff until you know it cold. He is the Guru of Candy propellant. I watched him cook up a batch for a K motor in my kitchen once. The wife did wonder what the smell was.

I wouldn't be trying any additives until you got the basic formulation down. In particular I'd skip the FeO. It's a standard burn rate enhancer for APCP, I use it in most formulations; but I don't think it would do anything useful in Candy.

And as the previous thread mentioned; the hard part in the do-it-yourself motor biz is making your motor stay together. Making propellant is like making bread, ugh except for the high temps and such. Once you get close there are a near infinite number of formulations that work OK. But making a motor that has, a nozzle that stays together and is properly sized; a lining that doesn't burn through; a case that doesn't let go; etc., etc. is much more challenging. But it sure gives you a lot to study and learn.

Also check to see if there are any Tripoli ( sites in your area. You can see some great launches and likely meet guys who do some motor building.

IndependentBoffin - 27-6-2011 at 08:01

One thing to note is that since solid rocket propellants generate gas (pretty much by definition), a sample of burning propellant tends to sputter smaller bits of burning propellant around.

Please do keep this in mind when testing a small batch next to your main batch, or anything inflammable :o

Safest place to test your rocket propellant samples are either in an earthenware flower pot or trough, or in a depression in a sand box/in the ground.

White Yeti - 2-8-2011 at 14:07

"Ammonium nitrate decomposes into N2 O2 + maybe it isn't ammonia I"m smelling?"

It's a good idea to note that ammonium nitrate decomposes explosively...

"While cooking I got a whiff of some of the fumes and they immediately made my lungs close up and I had to back away."

Do you have asthma?
I'm serious, I accidentally inhaled SO2 once, and I have asthma related problems, it knocked the air out of me for an entire 10 minutes, followed by a few hours of wheezing. There might have been SO2 production from the decomposition of metabisulfite.