Hello :)
I created this thread to discuss chlorate stability/sensivity based powders, especially the chlorate/sucrose powder, as this subjet doesn't appear to have been discussed before.
Chlorate powders are much more powerful than nitrate based powders, and for me, NaClO3 (which I can turn to KClO3) is greatly available in pure form whereas KNO3 is not, so it would be great to be able to use chlorate instead...

I heard a lot of things about chlorate/sucrose since I do pyrotechnics:
-"Chlorate powders auto ignite after 24 hours"
-"Minor temperature changes can ignite the powder"
-"Minor shock or friction can ignite the powder"
-"Chlorate powders are not that sensitive, just a bit more than BP"

So I searched on the net, and I found that:
http://www.jamesyawn.com/candyrocket/notes.html
-"chlorate mixtures can ignite with the least friction or from a minor shock"
-"Simply shaking a container of potassium chlorate and sugar can make it explode."
-"But a minute later simply inserting a spoon into the pile set it off"

Chlorate is described as very sensitive here, like it was AP ^^, so, what's the truth ?
I did some tests to find out:
-The first one, hammer impact: it ignited after several hits, and the one which ignited it was quite strong !
-The second one, friction test (with a teaspoon): no way to ignite it !

So, what I heard, what I read and what I tested, nothing matches !
Did the authorities published misinformation about that to avoid k3wls to blow-up their face, or am I just a paranoiac ?

If someone has some informations about that, it would be appreciated, thanks :D

Basically, while it can combust on minor friction, it's unlikely to. The point is to take adequate safety precautions and risk management.

Chlorates are sensitive in comparison to some other oxidising agents- perchlorates are a better choice here if you have safety in mind (and if you can obtain them, of course). I wouldn't worry too much about it as long as you do simple things like keeping chemicals separate and in a safe location. And don't mix chlorates with sulphur, you'll kill yourself ;) .

Ok, thanks :) yes, sulfur is not a great idea with chlorates, but I tried once with very small quantities (black powder with sodium chlorate), it's quite powerful !

Gerbil's warning should be emphasized. Sulfur and chlorates are not technically dangerous together. However, the sulfur will form traces of sulfur dioxide and hydrogen sulfide, both of which form acids in the presence of moisture (almost impossible to avoid). These trace amounts may/will form enough chloric acid to explode when hit. If you let it sit long enough and let the build up of these nasties continue, it may go off on its own. You may get away with it a few times, but the risk isn't worth it. Stick with perchlorates if at all possible. I know the majority of forum members are aware of this, but safety first. :D

A lot of Sulfur's reputation for sensitizing chlorate to the point of behaving like a contact explosive came from the days before Frasch process and/or refinery Sulfurs, which are quite pure as industrial chemicals go.

The old process of roasing Sulfur bearing rocks and letting the liquid Sulfur roll down a hill, or condense on a cold iron surface from vapor both produced large quantities of oxidation products. Additionally, the "volcanic sulfur" available in Europe in past times was contaminated with Arsenic sulfides, which REALLY will sensitize a chlorate mix to the point where sticking a spoon into it will cause an ignition.

There are a lot of older pyrotechnic mixes with sucrose as a fuel. They were storeable and functional on an industrial basis, particularly if sulfurless BP was used as the prime, if one was needed. Modern mixes and procedures tend to be safer, however.

I was wondering, why not adding NaOH / KOH (depending on what oxidizer is used) fine powder in small quantities in the powder ? so when the moisture comes in, NaOH / KOH will turn acids in Na / K salts, the powder would be more hygroscopic but safer, right ? It seems too easy :o

Feel free to test that out and get back to us. :D

I don't think you'd be able to grind NaOH into fine powder before it reacted with the ambient moisture in the air and form a nice mush. I might try it tomorrow at work. I need to make up some standard solutions anyway.

Ok, I'll try, I'll need to recrystallize a commercial solution of NaOH, the only thing I'll be able to see is if the powder behaves normally with moisture or not, I won't be able to see if the powder will be less instable/sensitive over time :(

I was wondering, why not adding NaOH / KOH (depending on what oxidizer is used) fine powder in small quantities in the powder ? so when the moisture comes in, NaOH / KOH will turn acids in Na / K salts, the powder would be more hygroscopic but safer, right ? It seems too easy :o

The hydroxides are too strong bases to be used in contact with pyrotechnic mixtures, especially Aluminum, Magnesium & their alloys.

MANY pyrotechnic mixes contain small percentages of carbonates as acid neutralizers. For some, the metallic carbonate is also a colorant, as with Strontium carbonate in Potassium chlorate and perchlorate oxidized red stars.

Copper carbonate is used in many blue and purple stars as the colorant as well.

Barium carbonate is a crappy green colorant, but 1% or so is often added to Barium nitrate or Barium chlorate oxidized green stars as an antacid. Their are a fair number of Sodium bicarbonate yellow mixes listed, but I hate that orangey Sodium yellow so I don't recommend them. I'd rather use mostly Barium nitrate with a small addition of cryolite or even Sodium benzoate to turn it from green to light, lemony yellow. With such a mix, a bit of Barium carbonate also serves well as the antacid.

Good idea, K2CO3 won't react with potassium oxidizers and it will give a great purple color, I've got 4kg KOH so it will be easy to get :) The only issue with K2CO3 is its hygroscopicity, maybe KHSO4 which is easy to make and not hygroscopic would be perfect :)
I'll try it soon to see how it behaves, to check if it's not hygroscopic and if it auto-ignites or becomes very sensitive in presence of sulfur over a long time period.

Good idea
Yes, an idea so good it's been in continuous use for over 150 years.
A little study of the existing litterature can save a lot of re-inventing the wheel.

Yes, an idea so good it's been in continuous use for over 150 years.
A little study of the existing litterature can save a lot of re-inventing the wheel.

Well, I meant... nice trick :D

I know it is an old thread, but Horrigan don't even tray to mix Chlorates and Hydrogen Sulfates !

You can't repleace a Carbonate (basic) with an Hydrogen Sulfate (acid).
You'll be getting Hydrochloric acid and that's what you are trying to avoid.

With CPSC's apparently impending success in limiting oxidizer sales, look for the amateur pyrotechnist to re-discover chlorate oxidized color mixes made with chlorate produced from supermarket bleach or pool chlorinator and water softener Potassium chloride, fueled with candy maker's superfine sugar or garden center Sulfur and colored with Copper, Strontium and Barium compounds sold by ceramic glaze suppliers or other non conventional pyro supply sources. (Or even home made colorants- My first chlorate blue and purple stars were made with my own fused Copper sulfide a la Weingart, home made from electrical wire and agricultural Sulfur).

Report mixes may revert to home made chlorate with Sulfur from the garden center and/or Antimony sulfide from your bullet casting metals supplier with charcoal (See Weingart for those 1800's "cannon cracker" powder mixes). My first Mag stars were made with a piece of scrap yard Magnesium plate, laboriously cut with a heavy wire wheel on a hand held angle grinder. Really made you appreciate those colors.

Of course, lift powder could be made from stump remover, yet more agricultural Sulfur and charcoal. (Let's just see them ban charcoal...) "When compost piles are outlawed, only outlaws will have nitre beds?"

We'll be back to the chemistry of the 1800's before you know it! And perhaps individual's levels of resourcefulness, grit, pluck and political involvement may also revert to the levels found in the USA a century and a half ago. Shortly after THAT, many problems could likely be solved-

Like the comment Bert. It would pretty funny to see the amateur pyrotechnist resort to using methods from the 1800's.

I had done a few propulsion tests with sodium chlorate/sucrose a while back, and was aware of the sulpher/chlorate issue. Being I was employing visco for ignition, I coated the end of the fuse with nitrocell. lacquer and experienced no issues. But from all the info out there, I felt lucky in this regard.

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There is no '-er' in Sulphur, nor Sulfur. NBK

This thread caused me to revisit the sugar/chlorate mix. I find it is a pretty darn good delay fuse mix when simply liquified and used to permeate a length of cotton string. A 50/50 mix, dried for 36 hours burns at about 20 seconds an inch, and is difficult to extinguish with snuffing, or air stream.

By liquified I sure hope you mean dissolved and not melted. It seems pretty obvious that it means dissolved when discussing drying time, but I've seen people do stupider things.

Oh dear :o.

I just boiled off the electrolyte from my chlorate cell and got about 200 grams of NaClO3 for my final yield. I haven't ever used chlorates for flash compositions, and now you've got me worried about the danger in storing it. I was planning on storing it in a plastic jar in a steel ammo box with the rest of my oxidizers. I read around and this looks safe, but just checking.

There should not be any problem with storing NaClO3 at normal temperatures in plastic.

Is there any particular reason you did not convert it to KNaClO3?

(edit)
Er, what's happened to the subscript...

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Nothing 'happened' to it, you just used the wrong style of tag. It's [ ] not < > NBK

Is there any particular reason you did not convert it to KNaClO3?Sodium chloride readily absorbs water from the air. By converting sodium chloride into potassium chloride- KClO3, you avoid the issue.

Plus, you end up with a somewhat better oxidizer.

Sodium chlorate also has a lower melting point than Potassium chlorate. This leads to a lower ignition temperature, and greater sensitivity of mixtures using it. Not to mention that Sodium chlorate is useless for making any color of star but yellow-

In my last post "KNaClO3" is a typo, I meant KClO3

As an old time pyro now in my 60's I can tell you that sodium chlorate has a much higher oxidation potential than it's potassium brethern, but there is that damn hygroscopic problem, overcome that and you've got a cheap and plentiful easy to aquire oxidizer.

Foot note: most pyro's I know do not allow chlorates in their labs and use them in a seperate area, designed for them. Use extreme caution when Chlorates are around.

Delta, I'll concede the oxidation potential issue, but the hygroscopic nature just ruins it for hobby pyro. Other than to hermetically seal a devise, water will get to it from the atmosphere. Commercial industrial uses are an exception.

Chlorates are indeed the bane of careless pyro's everywhere. Probably more f-ups w/chlorate-sulfur mixtures than all else combined.

A couple grams of sulfur can turn pounds of chlorate into an accident waiting to happen. Your reminder should be noted by all.