Questions about perchlorate and chlorate

[Visco]

I am new to the pyro hobby and have allot of questions. I have made rockets, smoke, bp and am working on my first 2"shells with D1 and have been reading about other star compositions. I've been looking at an array of cut or rolled rubber star formulas and have been buying my chemicals as I can and have a question. Most of the star formulas I have been looking at have potassium perchlorate and sometimes potassium chlorate in them but I see allot of don't use chlorate's. What is the risks with using these powders why do allot of people not want to use them? Only thing I can find is that potassium chlorate is not to be used with sulfur . Other than that what are the concerns? All information is welcome to further my knowledge. Please no just don't use them! I want to know why? And what the percautions are. Thank you all very much. You've been a big help so far.

[Paradise]

I am still VERY green in pyro but I can tell you some of what I know. Apparently chlorate comps can also be friction sensitive. If you had an ariel shell make a round trip chances are the shock from the shell hitting the ground would set off the chlorate containing stars and BOOM! Even more sensitive still would be if your comp contained metals. I've learned some folks here won't touch a device containing both. Far as the sulfer goes some will prime the chlorate stars with straight meal powder ONLY if the sulfer within is verified to be "pure" which I gather is mostly determined by the source of the sulfer by pyros far more experienced than I. The safest way to incorporate chlorates is sulfer free prime and burst (H3). 😉

[OldMarine]

Perchlorate stars are harder to light than the chlorate ones and a bit safer. There's a current thread here telling of a pyro setting his shop on fire apparently just by shaking some chlorate stars in a bucket.

[Visco]

So can the star formulas that contain perchlorate use bp as a burst charge? Only the chlorate can't? If I can't find hemp coal will homemade spruce or commercial charcoal work in place for the H3 charge.

[NeighborJ]

Clorate stars can be burst with bp if they are primed with a non sulfer containing prime. Ie.Monocapa, sulferless bp and H3. It is the sulfer which creates the undesirable friction sensitivity it can have a high acidity which creates another reaction when exposed to moisture. The spruce can work but you will want a very reactive charcoal to offset the lack of sulfer in the prime. Edited September 2, 2016 by NeighborJ

[OldMarine]

I've been working up to chlorate stars and I've repeatedly been told that a thick prime is a necessity to limit the friction/impact danger of these stars. I think the colors are worth the added risks myself but many choose to avoid them completely.

 

Hell, who wants to live forever?

[CrossOut]

Another option is to use non acidic sulfur in your sulfur prime as marine saidmake sure you put on a thick layer. Imo there aren't any good cheap color comps that can beat the old clorate ones. Just gotta be extra careful with them.

[Mumbles]

There are a lot of unfounded fears regarding chlorates. Compositions containing chlorates are more sensitive than perchlorates, but not notably so. Any pyro composition needs to be treated with respect. I think a lot of people would be surprised to learn how similar in sensitivies chlorate and perchlorates are. I would avoid compositions containing both sulfur and chlorates for reasons already mentioned. However having them in contact with one another is not the death sentence that it is sometimes made out to be. If it makes you more comfortable, don't use any sulfur containing burst or prime in your shells. You can prime chlorate stars with BP, and you can burst shells containing chlorate stars with BP. It has been done safely for decades. There has been a big shift over the past 20-30 years to produce very bright metal fueled stars. I personally feel that the benefits of chlorates are negated by the use of metals, while rendering more sensitive stars. To me, chlorates excel at organic stars and perchlorates excel at metallic stars. That's just my opinion of course, and people are free to see things differently or disagree.

 

Much of the chlorate hysteria came about when the common sulfur source was flowers of sulfur, which is a sublimed form and a notably acidic form. Currently much of the sulfur is a by-product of petroleum refining, commonly called sweetening. This form is actually quite clean. I usually seek out rubbermakers sulfur, which is generally produced via this process to the best of my knowledge and is a very clean form. The biggest concern

 

Other things that have noted sensitivities with chlorates are lactose(impact), antimony trisulfide(friction), arsenic sulfides, and red phosphorus (everything). All of these things are still used with chlorates for specialized applications, but you do need to be careful. You should keep an eye out of things that may contain sulfur or sulfides as well such as gilsonite and potentially some impure carbonate sources. I'm less sure about the actual danger of the carbonates since they're a natural buffer, but some do contain sulfides.

 

Barium chlorate is a slightly different animal. It is actually somewhat sensitive. For safety, performance, and economic reasons it is often cut with potassium chlorate and/or barium nitrate.

[Guest]

As im also new to this I have found this post to be great. To be fair I really try to stay away from chlorates and thus far have never used any.some storys really make me feel like they run a higher risk than I want.Im also somewhat scared skylighter may say im trying to make flash to make m80s if I buy any.I dont want to be cut off from buying at that store.

[Tim1877]

I was just wondering if there is any way to test your sulfur to see its acid content?

[OldMarine]

I've had my butt handed to me for asking the same question. This answer stuck:

"Sulfur was once recovered from volcanic deposits which contained adulterants which upon introduction of moisture would render sulfuric acid. Modern production methods render a purer product so the old chlorate fears are somewhat abated."

 

I have that printed out so I don't start getting too paranoid again. I like blue stars too much to avoid chlorates.

[PeteyPyro]

With regards to free acid in sulphur, I wash my sulphur with a solution of 2 table spoons of bicarbonate of soda ( baking soda) in 1 gallon of water. I use a dedicated blender to agitate the suspended sulphur. I test with my pool testing pH paper to ensure that there is a neutral pH. I then wash, filter, and dry it gently ( to ensure that the sulphur doesn't melt). I then mill it alone, with its own dedicated media, and in its labeled dedicated jar.

I try never to use any tool that has touched sulphur, to touch any comp that uses chlorate/perchlorate. Call me paranoid, but I still have all of my fingers and eyes, after 45~ish years in this hobby.

There is seldom a need to use any sulphur bearing chemical to enhance or sensitize a fp comp., unless using aluminum with little surface area to react. Good AL can easily produce explosive deflagration in sub-gram 70/30 fp, in my experience.

 

Stay clean and green, and keep them fingers.

[lloyd]

Petey, I'm sitting here, blinking kind of hard, and slowly shaking my head side-to-side.

 

In all those years of making pyro, has no one ever introduced you to acid-free rubber-makers' sulfur?

 

Lloyd

[rogeryermaw]

i've always done well with n.c. lacquer barrier coating. it's not a cure all but it has let me work in relative safety with both barium chlorate and ammonium perchlorate (shouldn't have to mention it but NEVER TOGETHER!!!!!!!) using simple b.p. based primes

[DesertCatUSN]

Does Antimony Trisulfide increase friction sensitivity with Chlorates only, or does it have the same effect with Nitrates like Ammonium Nitrate and Potassium Nitrate? Same question regarding lactose and impact sensitivity.

 

Also, what amount of each causes the change in sensitivity. Is it a small amount like less than 5%, or does it have to be a significant amount of the mix before it is of concern?

 

Finally, when you say lactose, what specific type and mesh are you talking about? I'm guessing we're not talking about powdered milk. Obviously a newbie to lots of this, so your patience is appreciated. Thanks!

 

Roger

[lloyd]

Sun,

Sb2S3, being a sulfide, tends to increase friction and/or impact sensitivity of any mixture to which it's added. However, it's not particularly a problem with anything but perchlorates (lesser) and chlorates (greater). It sensitizes in any amount, with sensitivity increasing up to about 15% of the mixture.

 

In any case, you should be mixing ALL materials (regardless of content) as if they were friction-sensitive. Screening is acceptable with almost all compositions as a means of mixing, but no 'device' like a squeegee or - worse - a metal object should EVER be used to force materials through a screen. At the most, only gentle wipes with the fingers of a hand. Shaking is preferred. But with chlorate mixtures containing any sulfur or sulfide, shaking ONLY.

 

Lactose is the sugar found in milk. It contains no portion of the milk except the "milk sugar".

 

Lloyd

[DesertCatUSN]

Lloyd,

 

Thanks for the info. I mix by gently shaking, not stirring. However, I've seen powder explosions and fires when the substance is aerated, as in a silo, or buildup of dust from flour or sugar. Even a sawdust canon on Mythbusters. Does that mean that powdered sugar, sawdust, or possibly flour would increase mix sensitivity? I've also read that powdered soap (regular Tide) has the same effect in small amounts when mixed with ammonium nitrate. Sounds weird, but is it true?

 

Also, I've read that mixing pure sulfur with chlorates is likely to result in an unexpected fire or explosion. Is that true, and would it depend on the ratio of Chlorate to sulfur? I'm not keen to have a mix unintendedly blow up on me or burn my lab down. Thanks again to any assistance.

 

Roger

[lloyd]

Roger,

Shaking a screen horizontally (NOT vertically), and fairly close to the surface on which the powders are deposited will not tend to aerate the mix much.

 

As for that, no 'conventional' pyro compositions are prone to ignition from aeration, anyway. I had an accident once with <2u magnesium, but that is a TINY particle of a VERY reactive metal. You'd not have much use for that material in 'normal' pyro compositions.

 

So-called "powder explosions" from dusts of flour and sugar are caused, not by the mere aeration, but by sparks (usually from static-electricity). Such dusts are not "pyrophoric" in their native state. The air is merely the oxidizer -- not the 'initiator' of the explosion.

 

The term "sensitivity" of a pyro composition is usually used to describe its tendency to ignite from impact or friction -- not from aeration.

 

I have no experience with mixing powdered detergent with AN... but why would you DO that? If I had to guess, any possible reaction might be due to the strongly-basic character of detergents... but I've never heard of that.

 

Lloyd

Edited June 17, 2017 by lloyd

[DesertCatUSN]

Lloyd,

 

Thank you. I don't know why they'd do that, but I read about the soap sensitizer in one of my military references. Unfortunately, I don't remember exactly where, should have marked the book and the location. And oddly, they emphasized regular Tide, in a low percentage. I guessed the particles themselves helped with friction, but that's an uninformed guess. Appreciate your patience.

 

Roger

[JTS]

Perchlorate stars are harder to light than the chlorate ones and a bit safer. There's a current thread here telling of a pyro setting his shop on fire apparently just by shaking some chlorate stars in a bucket.

The percussion/friction angle is the danger, though I've also been told that compositions containing Chlorate and Aluminum, with sulfur even somewhat isolated in the mix - the sulfur can "migrate" into the other chemicals and become ultra sensitive. It can happen over a period of time and become even more sensitive. Don't take the chance unless you're very qualified and have all the safety precautions for well established production companies. Never 'experiment' by adding mixtures of your own. There's plenty of literature available that can guide you safely.

[lloyd]

One example of a mixture that can become more sensitive with time is Dr. Shimizu's Napthalene black smoke star formula.

 

It contains chlorate, sulfur, and a large excess of napthalene as fuel. There's so much fuel in it that it's not even the least-bit sensitive to either impact or friction.

 

But....napthalene sublimes into the air at STP. So, after a time, the stars become fuel-poor, and the only primary constituents are chlorate and sulfur -- OOPS!

 

That's one of those formulae that needs a "best used by date" on it! <grin>

 

Lloyd

[DesertCatUSN]

Thanks! I'll stick with the known recipes. Roger

[PeteyPyro]

Hi Lloyd. I should have specified those precautions for when I have sulphur of unknown quality, or like 90+- % garden stuff. I don't think it matters much for bp, but H help me if I had any chlorate stars that got near bp with acidic S, tissue paper in between or not..............when I'm in the States (April-October) however, Phil's G,S, has some good prices on very low acid wetable RM sulfur....Duda D. too, in bulk. I still ALWAYS test it, because there have been cases of cheaper sulphur being relabeled as 99.95% pure / acid free. Maybe I'm just a bit paranoid, Lloyd. .. paranoid pyro Petey (clutching my litmus paper) <grin>

[Zippoman]

Chlorate is more shock sensitive then perchlorates