Sciencemadness Discussion Board

a question for experienced members

goblok - 11-2-2014 at 08:25

Can i use NaClO3 instead of KClO3 to make cheddite?

Zyklon-A - 11-2-2014 at 08:31

Yes, but it may not work as well, and you'll have to store it away from moisture. I've never done it myself, but it should work fine.

goblok - 11-2-2014 at 08:52

thanks a lot
I was afraid it would be a waste of time and money to try,
but now i'm pretty sure to make it.

Zyklon-A - 11-2-2014 at 09:17

Sure, but the proportions will be different, so you'll have to do the stoichiometry in order to make 'the biggest bang for your buck.':)

Bert - 11-2-2014 at 13:04

Although it will certainly work once you've made the adjustments to the proportions...

I would advise NOT using it.

The issue is the rather larger chance for it to set itself on fire during mixing and handling.:o

If you want Potassium chlorate and have Sodium chlorate and Potassium chloride, it's not hard to make. Soluability differences allow separation.

NaClO3 + KCl ---> KClO3 + NaCl

Potassium chlorate from Sodium chlorate & Potassium chloride


These were both dissolved in the smallest possible amount of boiling water. No insoluble matter was observed. The solutions were then mixed and left to cool slowly (so crystals would be large and easy to filter). After 24 hours, a large volume of white crystals of potassium chlorate had precipitated. The temperature was further reduced to 0 degrees centigrade, to push as much KClO3 out of solution as possible. The crystals were then filtered out, and rinsed with freezing water (to remove any NaCl solution on the surface). They were then dissolved in a minimum of boiling water, and cooled again. The precipitate was again washed and redissolved. A total of 4 wash, dissolve, crystallise cycles were used. The final crystals were parallelogram shaped.


Why The WiZ gets pains in his round-and-fuzzies when someone

A message on the West Coast Pyro Board and a recent article in
"Special F/X Newsletter" have made mention of the use of Sodium
Chlorate. There are one hundred and two really good reasons why
this oxidizer has not found use.

Reasons number; one, two, three -> # one hundred--IT IS NOT SAFE MIXED WITH -- ANY THING. PERIOD.


Case in point -- On the 27th of March 1952, four people were killed
and several injured in the chemistry building of Howard University,
Washington, D.C. when 400 pounds of sodium chlorate (possibly
contaminated with cardboard) being removed from a basement
storage room exploded. (Presumable from a electric spark
generated when a worker grasped the metal handles of the loaded
hand truck.)

A 1979 edition of the German medical journal "Plastische Chirugie"
(Plastic surgery) contain an article entitled: Mikrochirurgisch-
plasticsche Versorgung der explosionsverletzten Hand. (Mico-
plastic surgery for severe explosion injury to the hand.) "During the
last two years, 16 severe explosion injuries of the hand have been
treated with plastic microsurgery in our hospital. The injury had
arisen in seven cases FROM THE MIXTURE SUGAR + SODIUM
CHLORATE. This substance mixture may already be caused to
explode by slight vibrations and the warmth of the hands."

Photos accompanying the article show either; a victims hand, or a
squirrel that met a eighteen wheel'r while crossing the interstate!
No doubt an amazing bit of surgery. Well; I guess .... two and a half
fingers, and a toe are better then no hand! Must of hurt a bit

What we have here is a classic case of a low melting point fuel and
a low melting point oxidizer. A combination likly to be more then a
little sensitive/unstable.

By-the-by, one of the other cases was the resulted of the mixing
Potassium chlorate and red phosphorus. (For further info on this
combination, see my two articles in the American Fireworks News.)

Reason one-hundred-one is -- it is hygroscopic. (Which may
explain its sensitivity. For it is believed that the cycle of; absorption
of moisture followed by drying creates large unstable crystals, a' la
lead azide.)

Reason one-hundred-two is -- It contains (obviously) Sodium,
which will create a strong yellow light obliterating other colors.

While POTASSIUM chlorate has be used to good effect as an
igniter &c. when mixed with table sugar, and in combination with
lactose for smoke mixtures, it is NEVER to be combined with finely
powdered sugar such as confectionery sugar. For, combustion my
be a lot faster than you planned on. To your great regret.


[Edited on 11-2-2014 by Bert]

roXefeller - 11-2-2014 at 15:03

That post by THE WIZ certainly caught me off guard. I was always under the impression that KClO3 was the senstive cousin (I only played with chlorates a little in high school before my father found my stash and destroyed). I read the post and thought he would finish it with the punch line of "yeah, what do they know?" So NaClO3 is more sensitive and hygroscopic. I hate hygroscopic, especially lye. But at least with lye I don't have to think about losing my fingers while I'm cussing at it. If a girl were the same (clingy and prone to explosive fits), I'd apply for an order of protection. I'll take an explosive wife, and a clingy mistress. :D

Bert - 11-2-2014 at 17:01

To misuse a famous passage...

"Having eyes do you not see, and having ears do you not hear? And do you not remember?"

Sodium Chlorate melts @ 248 C., enthalpy of formation -53 kJ*Mol

Potassium Chlorate melts @ 356 C., enthalpy of formation -391kJ*Mol

And you already knew that Potassium Chlorate has a reputation for "touchy" mixtures?

From: Safety Report Assessment Guide: Chemical warehouses - Hazards

TNT equivalent of pure sodium chlorate: The explosive power of sodium chlorate is usually assumed to be .14.

The figure for pure ammonium nitrate is somewhere between .32 and .53, depending on conditions and who you ask.

There's a reason the original cheddite mixes didn't use Sodium chlorate except as a small percentage- even though it has allways been a cheaper chemical than Potassium chlorate. Cheaper ingredients won't lead to higher profits when the product, factory and workers keep needing to be replaced...

[Edited on 12-2-2014 by Bert]

Vikascoder - 11-2-2014 at 19:15

I have made cheddites with NaCl03 and they works main problem is that they are very hygroscopic so u need to store them very carefully . Its good to use the NaClO3 cheddite as quick as possible

Ral123 - 11-2-2014 at 22:37

The higher density of the sodium chlorate my contribute to lower burn speed in case of fire. Not sure of this one, only suspect. What makes the sodium chlorate mixture more unstable? Will it have lower storage stability. Let's not get hygroscopicity involved ok?

hissingnoise - 12-2-2014 at 02:52

Potassium chlorate has the higher density . . .

roXefeller - 12-2-2014 at 03:46

Quote: Originally posted by Ral123  
Let's not get hygroscopicity involved ok?

One of the speculations I read was the water involved causes large sensitive crystals to form.

Bert - 12-2-2014 at 06:18

Quote: Originally posted by Ral123  
What makes the sodium chlorate mixture more unstable?

If you can't interpret the melt points and enthalpy of formation of the various common oxidizers as signposts to the relative sensitivities of the mixtures made with them, you need to learn and keep in mind physics as it relates to explosives chemistry.

As for the melting point:

Solid with solid reactions proceed only at the contact points between particles, limiting the surface area available for reaction relative to that of a solid immersed in a liquid or gaseous reactant. To realy get things going at least one the reactants has to become a liquid or gas, allowing it to contact the COMPLETE surface area of other reactants - Hence the influence of melting point on sensitivity. Most pyrotechnic reactions really start to move around the temperature that one of the ingredients melts, generally the oxidizer. A low melting fuel like Sulfer or lactose can help provide a similar effect. How is a mixture of Sodium chlorate and Sulfer or lactose likely to behave? (Hint: use very small quantities if you want to see).

Look up the common oxidizers melt and decomposition temperatures, list them in order from low to high- Notice Sodium Chlorate has a rather low melting point, so it's going to take less energy to get the party started there.

About enthalpies of formation:

If energy was given off in the formation of a compound, you will need to provide at least that amount of energy to reverse that process-

Look at oxidizing Aluminum to Al2O3, which has a (relatively high!) enthalpy of formation of -1675.7 kJ*Mol. Lots of heat was given off there! (it also has a VERY high melting point...). Do you use it as an oxidizer???

Look at what I listed above for the chlorates:

Sodium Chlorate melts @ 248 C., enthalpy of formation -53 kJ*Mol

Potassium Chlorate melts @ 356 C., enthalpy of formation -391kJ*Mol

Do you use THEM for oxidizers? From the difference between those figures, which is going to make a more sensitive mixture, all other things being equal?

Further reading:

Conkling: Chemistry of Pyrotechnics- basic principles and theory