Notes on the use of potassium chlorate in sugar propellants, presented in a national magazine with widespread general readership.

Apologies for the repetitious and disorganized nature of the text below.  I will sort it out to a presentable form shortly....

In the meantime, maybe a list of topics will help some.

Basic Premise
History of chlorates
Sensitivity
Explosive nature
Safety procedures
Court cases
Use in bombings, terrorist activities
Manufacture/availability
Personal Experience
Safer Alternatives
Discussion list responses
Demonstrations
References


My primary contention:  I consider it irresponsible to demonstrate the use of a very dangerous chemical such as potassium chlorate to a general audience when much safer and more effective chemicals are in common use for the same purpose.

A warning "don't do this!" may provide some protection from liability but it will not prevent all readers from doing it.  Many young people read your magazine.  Some will have the means to do such experiments, but are likely to lack the knowledge, maturity, and judgement to do it safely.  Especially so if the article demonstrates unsafe experiments, thus promoting a casual attitude toward safety precautions. Warnings adequate to describe the safe use of this chemical would be lengthy, cumbersome to include in such an article, and their inclusion does not ensure that readers will follow them.  (See note 1)  

Potassium chlorate has a sordid history. It is the classic "basement bomber" chemical.  It is rarely used in rocketry, in part because it is very dangerous but also because other chemicals are more effective for the purpose of propulsion.  

Chlorate oxidizers are better suited for making explosives than rockets.  They form sensitive mixtures with some substances, which may ignite or explode from moderate friction or slight impact.  Sugar is one of those substances.  

If the intent of an article were to teach readers how to make bombs, then potassium chlorate would be a good choice, but even then a dangerous one.  Simply shaking a container of potassium chlorate and sugar can make it explode.  

Because of their instability chlorate mixtures can ignite with the least friction or from a minor shock.
Pyrotechnic mixtures made with potassium chlorate tend to be very fast-burning and thus more likely to explode.  If sufficient quantities are present, detonation is possible, even without containment.  Here are records of two court cases which illustrate the potential of this chemical:

http://online.ceb.com/calcases/C2/2C2d540.htm
http://online.ceb.com/calcases/CA2/119CA2d65.htm

In both cases, a teacher was sued for allowing a student to use potassium chlorate without adequate warning, and the student was badly hurt.  These cases are old, but potassium chlorate has not changed.  It is just as dangerous now as it was then.

Chlorates have been used for insidious purposes lately.  For instance, Theodore Kaczynski (aka "Unabomber") used potassium chlorate and/or sodium chlorate to make his explosives:
http://www.unabombertrial.com/documents/warrant.html

I've been told that sodium chlorate is being used with sugar to make an explosive used by suicide bombers, as sodium chlorate can be made from sodium chloride by electrolysis.  I understand that a number of the suicide bombers did not make it to their intended victims because the chlorate/sugar mixture is so sensitive that it explodes prematurely.

A few links:

http://www.capmag.com/article.asp?ID=3000

http://www.chinadaily.com.cn/en/doc/2003-08/08/content_253353.htm

Potassium nitrate (KNO3) is the oxidizer of choice for those who make sugar propellants.  KNO3 is commonly used with sucrose, dextrose, sorbitol, and a number of other sugars and sugar-alcohols (e.g. sorbitol) to produce viable propellants.  Nitrate/sugar mixtures are not very sensitive, harder to ignite, and slower burning on the average.  Thus nitrate propellants are much safer to make, handle, store, or use.

Sugar rocketry is thus seriously misrepresented by an article which illustrates the use of potassium chlorate.  

Publishing such an article using potassium chlorate will no doubt result in a flurry of "letters to the editor" denouncing the article.  These are likely to come from teachers, chemists, and others who know the history and understand the nature of this substance.  Pyrotechnists and rocketeers will be doubly concerned because accidents which occur during "rocketry" experiments could result in bad publicity and thus further restriction of our hobbies.

(1)  Working with chlorates safely requires substantial precautions and cautious procedures.
- working with very small quantities of any given mixture until the nature of the mixture is well known
- wearing face mask, fireproof gloves, and other suitable protective gear while working with pyrotechnic mixtures including chlorates
- avoiding the use of substances which create sensitive or unstable mixtures with chlorates.  Sugar is one of them.  Others include sulfur, phosphorous and compounds that contain sufur and phosphorous, and many organic fuels.
- avoid storing pyrotechnic mixtures in any tightly sealed container that might serve to build up explosive pressures.
- avoid storing in a hard container such as metal, glass, or hard plastic which could fragment if an explosion occurred
- avoid the use of screw caps or plugs that might cause excessive friction.  If a friction-type of cap is used, it must be kept clean of the pyrotechnic mixture
- avoid packing or ramming of any mixture in a casing without very substantial safety precautions.  Ramming such mixtures in a tube while holding it in the hand is one way amateur pyrotechnists lose fingers.

These opinions are obtained from a number of sources.  I have polled a number of knowledgeable rocketry folks, did some web searching, and looked at several references.  The more I research the use of potassium chlorate, and the way it is used in the article, the more ethical concerns I have about it.

Quick summary of what is below:

Bad news:  The use of potassium chlorate in a casual manner presents an unacceptable model for readers.  This chemical is very dangerous and should be handled with extreme care.  The author acted at great personal risk in mixing KClO3 with random substances.  Since this is the "land of the free" I am OK with that.  But to publish such actions in a widely-read magazine is not acceptable, as some readers are likely to emulate these experiments.  Potassium chlorate has a sordid past.  It is well-known among chemists, teachers, rocketeers, pyrotechnists, and law enforcement officials for its troublesome nature.  Responsible publication would require a long list of safety precautions and procedures to be engaged to attempt such experiments with reasonable safety.  An article promoting its use without adequate safety warnings will likely result in a flurry of unfavorable "letters to the editor."  

Good news:  Much safer chemicals are available, and work very well when used properly.  The article could, and in my opinion should, be rewritten to use these chemicals, and the results are likely to be more impressive. Over the weekend I made some propellant using potassium nitrate as the oxidizer and Pixy Stix as the fuel.  It works quite well, being very similar to the propellant I've been using for years.  Two weeks ago I used this propellant to launch my 10lb rocket to over 5000 feet.

I would be delighted to assist the author in any way to make these changes.  He can use any of my work gratis, and I will do whatever custom work this project might require.  I do not require recognition and am happy to simply support the promotion of good rocketry practice.
This is to avoid three things:

1.  Debilitating trauma to individuals who try the author's experiments and aren't so lucky
2.  Embarrassment to the magazine from negative letters, (hopefully not lawsuits!)
3.  Possible restriction of the hobby I love.

Long summary:

Potassium cholrate was discovered in the late 1700's, and led to a revolution in pyrotechnics when it came into common use in the 1800's. It allowed pyrotechnic compounds to burn with brilliant, true color. It offered loud, resounding reports from aerial shells.  It made brilliant flashes.  It was used in photography to take the earliest flash photographs.

But potassium chlorate also caused great hardship - many fireworks plants using chlorates exploded.  People lost life, limb, vision, and this hardship continues to the present.
A second pyrotechnic revolution began in the early 20th century, when it was found that potassium chlorate is unstable when mixed with certain substances.  Quite a number of them, in fact.  The isolation of chlorates from known sensitizers made its use much safer.  Fireworks plants exploded, but not quite as often.

A third improvement was made when acceptable alternatives for potassium chlorate were discovered, notably potassium PERchlorate (emphasis mine) which is similar in its oxidizing properties but much more stable. Potassium chlorate is still in use for specialized purposes, but less and less as safer compounds have been found to replace it.

Availability:

Potassium chlorate can be made rather easily from substances found in a grocery store.  Sodium chlorate is even easier.  Thus to assume kids or naive adults won't use it because they can't get it is false logic. Instructions on making chlorates can be found on the web with a simple search.  If you run a Google search for "making chlorate" you will get many hits, including several offering specific instructions.

Here are a few examples:

http://www.intekom.com/scotland/cookbook/003.htm

http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/chlorate.html

http://www.everything2.com/index.pl?node_id=510067



The problems of potassium chlorate stem from:

It is unstable when mixed with many substances.  Most notably sufur, phosphorous and their compounds, but also organic fuels, SUGAR, and metals.

Because of this instability it is sensitive to shock and friction. Chlorate mixtures can ignite with the least friction or from a minor shock.
Pyrotechnic mixtures made with potassium chlorate tend to be very fast-burning and thus more likely to explode.  If sufficient quantities are present, detonation is possible, even without containment.  Please look at this court case for an indication of the potential:

http://online.ceb.com/calcases/C2/2C2d540.htm

This case is old, 1935.  But potassium chlorate has not changed, it is as dangerous now as it was then.  

Here is a similar case from 1953:

http://online.ceb.com/calcases/CA2/119CA2d65.htm

In both cases, a teacher was sued for allowing a student to use potassium chlorate without adequate warning, and the student was badly hurt.

People have found safer substitutes, which is the gist of this long note.

Chlorates have been used for insidious purposes lately.  For instance, Theodore Kaczynski (the "Unabomber") used potassium chlorate and/or sodium chlorate to make his explosives:
http://www.unabombertrial.com/documents/warrant.html

I've been told that sodium chlorate is being used with sugar to make an explosive used by Palestinian suicide bombers, as sodium chlorate can be made from sodium chloride by electrolysis.  I understand that a number of the suicide bombers did not make it to their intended victims because the chlorate/sugar mixture is so sensitive that it explodes prematurely.

Sensitivity?  I can vouch for that!, with an emphasis on the "ouch" part of it.

My Personal Experience

Years ago I was burned when making black powder using potassium chlorate.  I had been making black powder using potassium nitrate for a long time, had developed a method for making modest amounts that worked pretty well.  I had never experienced an unexpected ignition.  But someone had given me a small amount of potassium chlorate, saying that it was "more powerful" than KNO3.  So I tried it.  I had mixed up about a tablespoon of the dry powder using my normal method, and was preparing to test a small amount by burning it to see how quickly it burned.  As I inserted my lab scoop into the pile, it ignited.  The friction of the spoon moving through the powder was enough.  I was very fortunate.  The amount of powder was small and not contained so it did not explode, it just burned instantly.  I suffered second-degree burns on that hand - painful, but it healed.  If the amount had been larger, the mixture could have detonated and I would likely have lost vision and/or body parts.

Potassium chlorate is capricious.  In the event I just described, the explosive mixture had endured grinding from coarse chunks to a fine powder without incident.  But a minute later simply inserting a spoon into the pile set it off. Moral of this is that just because one gets away with it once, twice or three times doesn't mean it will not ignite on the fourth or fifth.  


This is the kind of danger I believe we shold encourage people to avoid. At least to warn, so that the danger is known.  Unfortunately, with chlorates, ample warning would take up most of the article, and many folks wouldn't be willing or able to follow them.  It would be far more responsible to use an accepted, stable chemical, especially when the safer chemical works better.
Back to the "candy rocket" article.  The author may know enough about chlorates to use them safely himself, but it seems unlikely.  If he did, he would be much more wary of sharing this information with the general public.  And he would be using much safer chemicals that can do the job better and with much lower risk.
I don't know if you hold much sway with the author of the article or the editors of the magazine, but I implore you to seek ways to get this article modified so that it does not encourage readers to try extremely and unnecessarily hazardous experiments.  Mixing chlorates with random substances is a very good way to get hurt. The author of the article was either very lucky, or exercising cautions that have not been described to me.  I suspect it is the former.
References on this issue:

Publications on rocketry and pyrotechnics invariably warn against the use of potassium chlorate in any propellant.  For example:

>From "Fireworks",  Shimizu, Takeo;  3rd ed  Pyrotechnica Publications  1981

"But it has been a matter of sincere regret that potassium chlorate has often
caused explosive accidents. It would be ideal to reject this material from
fireworks...."  Page 90


>From "Experimental Composite Propellant", McCreary, T.W., Copyright 2000

"...as of this writing I have heard ten (presumably reliable) accounts of
accidents involving experimental propellant and motor making.  In EACH CASE the
accident arose from a clear violation of reasonable safety guidelines.  The
accidents included:
-use of chlorate compound in propellant
-smoking near propellant
-trying a new unknown formulation in other than tiny quantities
-standing near propellant scraps that were being ignited
-mixing incompatible ingredients while dry
-failure to use safety equipment
-drilling an inappropriately sensitive composition
-failure to test launch system properly"            Page 2



>From "Rocket Manual for Amateurs", Capt. Bertrand R. Brinley,  Ballantine Books,
1960  1st publication.

"The most readily available chlorates, sodium chlorate and potassium chlorate,
are so friction sensitive that they will detonate when ground or rubbed in a
mortar <and pestle>  They are not used even in professional propellants for
this reason. The perchlorates are more stable, but are still dangerous."
Page 71-72



>From "Amateur Rocket Motor Construction," David Sleeter, The Teleflite Corporation, 2004

"1.  Important Information & Safety Procedures.

First and MOST IMPORTANT! Do not add or substitute other chemicals either to-or-for the chemicals listed in this book!  Specifically, do NOT use POTASSIUM CHLORATE, SODIUM CHLORATE, POTASSIUM PERCHLORATE, SODIUM PERCHLORATE, POTASSIUM PERMANGANATE, AMMONIUM PERCHLORATE, PHOSPHOROUS, MATCH HEADS, ALUMINUM, MAGNESIUM, or ANY METALS AT ALL!  All of these substances will form DANGEROUS and EXPLOSIVE mixtures when combined with the other ingredients described herein..."  Page 1

Yes, there are other dangerous chemicals besides potassium chlorate, but it is among the worst.



Interactions with the SugPro discussion list

Here is the note I wrote to members of the sugar rocketry discussion list, summing up what I felt to be the consensus of previous messages on this list.  (Please note that "KC" is their abbreviation for "potassium chlorate" and "KN" means "potassium nitrate.")


James Yawn wrote:


It seems to be agreed that:

1.  Potassium chlorate can be used in rocket propellant.  Some
experienced rocketeers (and many pyrotechnists) use it with reasonable
safety.  It offers advantages over potassium nitrate for some limited
purposes.

2.  Potassium chlorate is difficult to tame.  It is easy to make it
explosive, harder to make it a propellant.  It is so troublesome that
many experienced rocketeers have tried it and discarded it for reasons
of excessive danger, low reliability, or ineffectiveness for their
purposes.

3.  Potassium chlorate is extremely dangerous when used improperly, and
using it "properly" is not easy.  Most beginners will use it in a very
dangerous fashion unless trained how to handle it, and that training is
not readily available.  Thus potassium chlorate is NOT a good chemical
for beginners to use when formulating rocket propellant.

4.  Potassium nitrate is preferred by most sugar propellant users as it
is far safer, non-toxic, less expensive, and quite effective.  Even it
must be used with extensive safety precautions, but overall it is a much
better oxidizer for a beginner to use.


Is this something we could agree upon, more or less?


I would tend to agree with all four statements, based on my limited
knowledge of KC. (Richard N)


So what to do, what to do.  I am thinking of suggesting to the
fact-checker that he ask the author to repeat his experiments using
potassium nitrate.


I doubt if such experiments would be successful in replicating the
results. In fact, KN does not react effectively (enough to serve as a
rocket propellant) with most materials -- that is one reason why it is a
"safe" oxidizer for amateur use.

Richard N


William C. writes:

Jimmy,

I hesitate to bring up this issue, but it is relevant.

This is a hobby that many in government would like to
see cease.

The mention in "October Sky" of KClO3 was bad, I
thought and might have engendered some accidents
around the country, especially with young people
experimenting with new substances due to exercising
their young creative minds.

My opinion again would be to attemt to convince the
magazine in question not to publicize the use of KClO3
as a propellant oxidizer.


Bill W. writes:

FWIW, I've heard people in the pyrotechnics/fireworks community claim that
Ammonium perchlorate exhibits sensitivity issues similar to potassium
chlorate.  Given the danger of the two getting anywhere near each other
(allowing ammonium chlorate to form), the professionals tend to choose KC as
the more versatile "potentially dangerous chemical" to deal with.  KC has a
lot of things that you shouldn't combine it with, but in a "professional"
context, those are not difficult to avoid.  The chief danger with KC seems
to be in the "amateur" context, where one is more likely to go about mixing
it with random substances until they accidentally find one that goes boom.

Recomending KC in a context where one has done EXACTLY that (combined it
with random substances) does seem especially irrespsonsible, though.
KN based compositions seem to have a wide safety margin; there are very
few things that people have experiemented with on this list that have
made be cringe.  Start doing the same class of experiments with KC, and
I'd be very nervous...


Jim F

1) Chlorates when mixed with any fuel create dangerously flammable and

explosive mixtures that are  EXTREMELY sensitive to friction and heat.

Pyrotechnicians and rocket builders religiously avoid chlorates in all

but some very specialized and carefully controlled mixtures, and

UNIVERSALLY speak against use of chlorates by any casual experimenter.



Chlorate compounds make matches work. Some home rocket makers in the

60's attempted to use crushed match heads to fill casings for rocket

motors, with often disastrous results. Hence the nickname "basement

bombers" for rocket makers who did not do their homework. Amateur rocket

makers today have excellent records of safety, through careful research

and thorough safety precautions.

End for now.
Jimmy Yawn
jyawn@sfcc.net
3/31/06