KClO3 and sulfur general compatibility

[JTO]

It is said that one should never use both in the same composition, but in pyrodata.com there are EIGHT star compositions, ELEVEN burst/report compositions and ELEVEN flash compositions which contain both substances. How is it possible, or is the whole compatibility issue a myth?

 

I recall that match heads contain both substances and I've never heard of a match box spontaneously igniting. Moreover they are often kept in high temperature, for example close to a fireplace, and they do not ignite.

https://pyrodata.com/composition/stars?tid_1%5B%5D=8&tid_3%5B%5D=72&title=&field_video_video_url=All&description=All&description_1=All

 

https://pyrodata.com/composition/burst-charges?tid_1%5B%5D=8&tid_3%5B%5D=72&title=&field_video_video_url=All&field_table_check_value=All&description=All&description_1=All

 

https://pyrodata.com/composition/flash-powder?tid_1%5B%5D=8&tid_3%5B%5D=72&title=&field_video_video_url=All&field_table_check_value=All&description=All&description_1=All

 

[Arw]

Risk has different level and You choose that what you give and what you get my friend.

Edited September 14, 2021 by Arw

[mabuse00]

There are a lot of antique formulas in such compilations, imho added for the sake of completeness.
In most cases they do not offer any advantage over more modern non-chlorate ones.

You simply do not need them.

In fact, you do not need chlorate at all, apart from a few niche applications.
The only reason to use it is either you happen to have it or you make it yourself.
Especially when you live in a political environment where you cannot get perchlorate.

"Incompatible" can mean several things, from "ignites by itself" (in the past sulphur often contained traces of acid) to "unnecessary sensitive, but usable".

[SeaMonkey]

Here is an interesting video from about 4 and 1/2 years ago where the Friction Sensitivity of various proportions of Potassium Chlorate and Sulfur were tested.

[Crazy Swede]

It is all about pH!

 

If your sulfur is non acidic and your composition has some kind of pH buffer, like MgO, it will be stable for storage. Still very sensitive to friction but it will not spontaneously ignite

[Arthur]

The issues are not always the indicated elements, BUT the impurities associated with their various methods of manufacture over the last hundreds of years.

 

In prior centuries sulphur was found and mined naturally but it contained significant traces of acid which was enough to trigger reactions. Modern sulphur comes from oil refining as a by product of making extra low sulphur road, marine and aviation fuels.

 

However, nothing has ever been said to be dangerous without reason, especially in an industry that makes inflammable things. While old formulae had lots of chlorate and sulphur compounds -because they worked- the comps lead to products that didn't store well or could be sensitised by humidity cycles. As a result of some serious spontaneous explosions in England work rounds to avoid chlorate/sulphur comps were developed leading to the development of perchlorates and leading to the pre-washing of sulphur.

 

Nowadays there is very little reason to use chlorates -they increase sensitivity, or chlorate/sulphur comps -due to their sensitivity. Where there really is a need for chlorates is some sensitive products like old primers and some cool burn comps like smokes. For good reasons professional pyro manufacture minimises the use of chlorates to minimise the risk from chlorate comps and from cross contamination.

[sefrez]

I hate chlorates with regards to accepted "incompatibilities", of which I abide to the best of my knowledge in pyrotechnic devices, but I love them because they are easier to make than perchlorates and work better (in my experience.) Decent colors can be achieved without metals and using less chlorine donor. They also ignite easier and don't go out as easily, again in my experience. This goes along with its higher sensitivity compared with the other oxidizers.

 

Though I have done some tests with chlorates to find conditions seeming to be specific for an accident to happen. Although these test suggest to me the sensitivity of chlorates as claimed by the general community are a little exaggerated, I still choose to take those claims seriously because any conclusion I come to on the contrary need stand tall against the vast dealings with chlorates giving them a "bad name."

 

On small scale, I have mixed stoichiometric amounts potassium chlorate and sulfur (according to 2KClO3 + 3S -> 2KCl + 3SO2) and added drops of ~80% sulfuric acid to it. Upon doing so, I observed much heat produced and redox reactions from the gases being released. Sulfur dioxide was definitely present by scent, but I imagine chlorine and chlorine dioxide were also being produced. I thought for sure the mixture would ignite, but it just simmered down and I neutralized the acid to end the test. Its been a while since I did this test and can't remember how much acid I added to the composition, but its possible I added enough that it actually diluted the composition which could of possibly had the effect of preventing the above reaction from ultimately taking place.

 

I added the same acid to a small amount of H3, and that was a very violent reaction. I would have guessed it the other way around. I didn't do a test on a mixture containing all three (oxidizer, sulfur and charcoal.)

 

I did try ~30% HCl on H3 as well. It mostly produced Cl2 and ClO2. Not much heat and no ignition.

 

All that said, I still keep the acids or acid forming compounds far.....far.... away from chemicals ready for pyrotechnic usage. Oh, and ammonia or ammonium compounds.

[SeaMonkey]

Interesting account of your dripping concentrated Sulfuric Acid onto various Chlorate mixtures.

 

The one mix which will inflame by adding a drop of Sulfuric acid is the Chlorate-Sugar mix.

 

Whether 80% Sulfuric Acid will ignite the mix reliably I cannot say.

 

But the 80% can be concentrated to about 93% quite easily.

[Arthur]

Remember that chlorate was the essential ingredient for colour comps for years (and some others). It wasn't an option it was essential. However since the advent of perc which is far safer there is little need to use chlorate. While the incompatibilities of chlorate are known and some are more hazardous than others it's always easy to look for a more stable alternative, usually there is one, just occasionally there is no choice.

[JTO]

Here is an interesting video from about 4 and 1/2 years ago where the Friction Sensitivity of various proportions of Potassium Chlorate and Sulfur were tested.

Thanks! Somehow I had missed it in Youtube, very informative.

[JTO]

There are a lot of antique formulas in such compilations, imho added for the sake of completeness.

In most cases they do not offer any advantage over more modern non-chlorate ones.

 

You simply do not need them.

 

In fact, you do not need chlorate at all, apart from a few niche applications.

The only reason to use it is either you happen to have it or you make it yourself.

Especially when you live in a political environment where you cannot get perchlorate.

 

"Incompatible" can mean several things, from "ignites by itself" (in the past sulphur often contained traces of acid) to "unnecessary sensitive, but usable".

 

 

The application which I have in mind is that I have made some spolette timing fuses which have a BP + dextrin core and I was thinking about dipping the end of the spolette in H3 primer (75%KClO3 + 25%C + some dextrin) to ensure ignition, because I think the H3 ignites more easily. Which would mean that the H3 comes in direct contact with the BP. But I am weary about its safety, especially in long term storage. What do you think? Also, my stars are primed with H3 and I intend to use BP as burst charge, which brings the same problem, except in the latter case the BP and the H3 are not going to be fused together when wet, merely inside the same shell and in "dry" contact with each other.

[Arthur]

Have you considered sulphurless powder?

If you make a spollette with one increment of sulphurless powder between the BP and the H3 you have eliminated one possible incompatibility. If you use BP as burst then you could give the stars an outer prime of sulphurless powder.

 

Sulphurless powder having several ratios between 70 ; 30 and 87 ;13 according to the source.

[mabuse00]

Generally you should decide on a full chlorate or non chlorate system, without all those changeovers.

I mean, you have both chlorate and sulphur dust in your workplace, on your tools ect.

(Chlorate is easy to clean though, beeing water soluble...)

 

Sulphurless BP would indeed be a solution.

 

 

I was thinking about dipping the end of the spolette in H3 primer (75%KClO3 + 25%C + some dextrin) to ensure ignition, because I think the H3 ignites more easily

I doubt that H3 ignites more easily than BP of at least medium quality.

 

Also your burst charge is BP - that is the next critical changeover, perhaps the stars bounce on it when you accidentaly drop the shell. With sulphur in between - hmmm...

I think thats more critical then H3 merely laquered obove BP.

 

 

 

edit:

 

my stars are primed with H3

Might be irrelevant now, but why did you do that in the first place?

Chlorate stars I assume?

Edited September 21, 2021 by mabuse00

[sefrez]

For spolette ignition, I use small black match. I leave room on the ignition side of the spolette to insert two/three strands. Also, in the making of the spolette, the ignition side has a former I made out of brass that when the composition is pressed against, it leaves a concave cone. This gives greater surface area between match and composition for better ignition.

[JTO]

Yes, my stars use KClO3, because I cannot get KClO4 where I live. I cannot get KClO3 either but I make it.

 

I have a couple of ideas. First, I am going to replicate my BP/H3 mixtures by putting a small quantity of BP and a couple of H3 primed stars, and also a piece of the h3-primed BP spolette which I made, in a small plastic container. Then I am going to store it indefinitely in a safe place, and shake it with all my might every once in a while (with adequate protective gear). If it never goes off, I can be reasonably certain that my devices are safe :-) Also, I am going to start experimenting with the sulphurless compositions soon, I am just making my first prototypes of a simple airburst device. I am going to use sulphurless ones in my next generation devices.

 

Generally you should decide on a full chlorate or non chlorate system, without all those changeovers.

I mean, you have both chlorate and sulphur dust in your workplace, on your tools ect.

(Chlorate is easy to clean though, beeing water soluble...)

 

Sulphurless BP would indeed be a solution.

 

I doubt that H3 ignites more easily than BP of at least medium quality.

 

Also your burst charge is BP - that is the next critical changeover, perhaps the stars bounce on it when you accidentaly drop the shell. With sulphur in between - hmmm...

I think thats more critical then H3 merely laquered obove BP.

 

 

 

edit:

Might be irrelevant now, but why did you do that in the first place?

Chlorate stars I assume?

 

[Richtee]

I’’ll add sulfur-less BP is not very easy to ignite. If that’s a problem, you might search other avenues for your application.

[JTO]

I’’ll add sulfur-less BP is not very easy to ignite. If that’s a problem, you might search other avenues for your application.

Do you mean, as a burst charge? If you used it in a spolette, priming the end with H3 would surely make it easily ignitable.

[Richtee]

Do you mean, as a burst charge? If you used it in a spolette, priming the end with H3 would surely make it easily ignitable.

OK. Then it’s not a problem.

[BigBoomTeen]

Hi JTO,

I'm a noob around here and to this hobby, but I have heard that pyrodata.com is not always reliable. If that is what is causing this confusion for you, you may want to consider double checking the information by other sources.

[JTO]

Thanks! It seems to me that pyrodata.com has tons of compositions from all kinds of sources, some are clearly erroneous. Many might be very old and nobody has evaluated their safety.

Hi JTO,

I'm a noob around here and to this hobby, but I have heard that pyrodata.com is not always reliable. If that is what is causing this confusion for you, you may want to consider double checking the information by other sources.

 

[Bourbon]

I agree... There has been a lot of talk on that subject (pyrodata) around the forums. Folks are encouraged to ask questions, not only about formulas, but their procedures, which in most cases there are non at all (crazy).

 

I'm not the guy to ask... But I trust the folks saying be cautious. I'm certainly not saying ProData is dubious.

[mx5kevin]

KClO3 with sulfur are extremely sensitive from friction! Using less acidic ventilated pure sulfur powder (and not granulated sulfur) are important.

 

The KClO3 friction sensitivity can be reduced temporarily before direct use. The method significantly reduces friction sensitivity for a short time.

 

1. The KClO3 must be grinded to fine powder this is important and heated 200-300°C to be completely free of moisture. If the KClO3 not grinded, the process is less effective.

 

2. Must be used +5% KHCO3 potassium-bicarbonate for the total KClO3 (and not K2CO3 Potassium carbonate because this is much stronger alkali) when the KClO3 are cooled down. Example 10g KClO3 (grinded+heated) +0,5g KHCO3 must be grinded together.

 

3. If sulfur are used (in extreme cases) 1/4 of the KHCO3 are grinded with the sulfur. (In most cases, KClO3+Sulfur a young beginner is experimenting with some unprofessional recipe.)

 

The method makes all kinds of compositions safer where KClO3 are used and friction or compression occurs like in colored smoke bombs where KClO4 burns too high temperature.

 

The other method like making matches or exploding air rifle pellets was mix them wet together „with some glue".

 

Where flash powders, star compositions, whistle mixes, used KClO3 most of them non-professional recipes. KClO4 with sulfur a compatible, KClO3 are not! In most cases, there is no need to use KClO3.

[pyrojig]

In my recollection, you can use even BP primed chlorate stars with acid free sulfur. I have done this in past. Even had a dud shell with those stars ( bad time fuse) in my early pyro years. The shell hit hard ground and no ignition occurred. Loose separate components like chlorate stars and BP may on the other hand react to hard impact. This info was from Shimizu's book I believe. As stated , if not needed why attempt using sensitive chlorate with BP when you can just use h3 or kp burst sys.