41 replies to this topic

[Potassium chlorate]

I don't store things for a long time, and I use protection against the toxic stuff, but potassium chlorate and hexamine might be as dangerous as potassium chlorate and ammonium perchlorate.

That one looks interesting, though. Wish one had time to test them all.

[Creepin_pyro]

potassium chlorate and hexamine might be as dangerous as potassium chlorate and ammonium perchlorate.

I don't recall hearing about that one. Is it chlorates in general or just Potassium? I don't currently use chlorates but am planning on doing a few tests with Barium Chlorate, would be useful to know what to avoid mixing it with.

[Potassium chlorate]

I don't recall hearing about that one. Is it chlorates in general or just Potassium? I don't currently use chlorates but am planning on doing a few tests with Barium Chlorate, would be useful to know what to avoid mixing it with.

Hexamine is made of formaldehyde and ammonia. And ammonia and potassium chlorate is a big no-no, since it might form ammonium chlorate.

Barium chlorate is probably a bit more stable, but I wouldn't trust any chlorate together with ammonia or any ammonium compound.

[seymour]

From Shimizu, page 104 of FAST

"It has been said that compositions which contain Barium chlorate are more sensitive than compositions which contain Potassium chlorate and sometimes cause spontaneous ignition in the sun".

I've heard similar things from other sources. Indeed, I believe Barium chlorate is the most sensitive oxidiser used in fireworks, though Potassium chlorate and Ammonium perchlorate are not too far behind.

[Potassium chlorate]

From Shimizu, page 104 of FAST

"It has been said that compositions which contain Barium chlorate are more sensitive than compositions which contain Potassium chlorate and sometimes cause spontaneous ignition in the sun".

I've heard similar things from other sources. Indeed, I believe Barium chlorate is the most sensitive oxidiser used in fireworks, though Potassium chlorate and Ammonium perchlorate are not too far behind.

I think this might be wrong, even if it is a statement from Shimizu. Barium chlorate releases more energy once ignited, but it also takes more energy to activate it.

Though no matter what, all chlorates should be treated very carefully.

[Maxim]

Thinking about valency, why would barium chlorate be more unstable? Barium forms ions with 2+ charge while potassium forms just +1?

[Peret]

According to Shimizu, page 89, chlorates are slowly decomposed by ultraviolet light to chlorites and chlorides. "Potassium chlorite, KClO2, ignites or explodes in contact with sulphur or a sulphide and potassium chloride, KCl, as described above. Therefore the chlorite probably promotes the decomposition of KClO3 when it is heated. Of course, the amount of potassium chlorite or chloride may be too small to cause a spontaneous explosion, but ultraviolet light does not improve the quality of potassium chlorate."

[Mumbles]

I think this might be wrong, even if it is a statement from Shimizu. Barium chlorate releases more energy once ignited, but it also takes more energy to activate it. Though no matter what, all chlorates should be treated very carefully.

Are you sure it takes more energy, or do you just mean harder to light? It's known to be a pretty sluggish oxidizer, so it could just take longer to get going to a self sustaining state. Rate and energy are not always perfectly correlated. I thought it was pretty common knowledge that barium chlorate was more sensitive than potassium chlorate, which would indicate a lower activation energy. Barium chlorate/shellac stars are known to be quite sensitive to impact and friction. The analogous potassium chlorate mix is less sensitive. In fact replacing some of the barium chlorate with potassium chlorate (or barium nitrate) are known to speed up the burn speed and decrease the sensitivity.

Thinking about valency, why would barium chlorate be more unstable? Barium forms ions with 2+ charge while potassium forms just +1?

Well it depends a lot on the crystal structure, but barium 2+ and potassium 1+ are almost the same size. That being said, barium exerts a harder pull on the counter ions, which could weaken the chlorine-oxygen bond. Whether this has anything to do with reactivity is up for debate though.

[Potassium chlorate]

Are you sure it takes more energy, or do you just mean harder to light? It's known to be a pretty sluggish oxidizer, so it could just take longer to get going to a self sustaining state. Rate and energy are not always perfectly correlated. I thought it was pretty common knowledge that barium chlorate was more sensitive than potassium chlorate, which would indicate a lower activation energy. Barium chlorate/shellac stars are known to be quite sensitive to impact and friction. The analogous potassium chlorate mix is less sensitive. In fact replacing some of the barium chlorate with potassium chlorate (or barium nitrate) are known to speed up the burn speed and decrease the sensitivity.

Barium chlorate might more easily detonate on impact. I read in an old encyclopedia that it might detonate on impact without any fuel, though I have never succeeded in making that happen (a 15 kilo sledgehammer on an anvil with barium chlorate didn't make it happen). Though I'm not sure if that means that it will also more easily spontaneously react with stuff like sulfur or hexamine. I read somewhere that the stability of a chlorate might be determined by the stability of its end reactants. The end reactant of barium chlorate is barium monochloride. It first decomposes to barium dichloride and then to the monochloride. For what I know, barium monochloride is more stable than potassium monochloride, but someone may correct me, if I'm wrong in one or both of these assumptions.

[FrankRizzo]

What's the particle size of the MgAl in your formula, Seymour?

[Peret]

Here's Ellern on chlorates (Military and Civilian Pyrotechnics, chapter 43)

In forming anions from chlorine and oxygen atoms, the stability of the anion increases with the number of oxygen atoms, from hypochlorite to chlorite, to chlorate, and to perchlorate. This difference is still pronounced at the last step between chlorate and perchlorate.
...
The stability of the chlorates declines with the increase of valence of the cation. Barium chlorate, normally forming a monohydrate that loses its water above 120°C, is somewhat less stable than potassium chlorate.

[Potassium chlorate]

You're all against me!

[pyrotrev]

I'm fascinated. I can make this for certain right now, except for the red gum (and honestly, I don't plan on buying any soon). Can that be substituted? Also, can we see this composition in action on video either as a star or a loose pile?

The only things I can think of that would be a close replacement for the red gum would be powdered phenolic (novolac) resin or resorcinol resin adhesive. DExtrin has a much lower carbon content and I suspect the burn rate will reduce.

[Potassium chlorate]

What about powdered shellac? It's more suitable for chlorates than perchlorates, but since there is a second - strong - fuel, MgAl, that shouldn't be a problem.

[seymour]

While the Red Gum certainly has a significant fuel value, half the reason it's in there is to reduce stickeyness when using Parlon as a binder.

I'm sure replacing the Red Gum with Shellac would work OK, but I'd prefer to replace it with a larger quantity of Dextrin for more reason than one. By adding 5% or 6% dextrin to replace the 4% RG I'd be compensating slightly for the lower fuel value, but primarily I'm adding a water soluble binder.

Additionally, in my experience Dextrin is actually quite a good fuel with Potassium perchlorate.

My suggestion to use dextrin was not really a suggestion made to most accurately replace the Red Gum, which Phenolic compounds would probably do better.

FrankRizzo

Posted Yesterday, 11:25 AM
What's the particle size of the MgAl in your formula, Seymour?

I use -100# in all my colours.