40 replies to this topic

[a_bab]

BC = barium chlorate (as in Best green Color)

As the good greens are elusive to me and the ones saying that "BC green is arguable the best" obviously never saw a green obtained by BC/shellac, I'm considering more and more to use it.

But, BC it is known as giving among the most sensitive compositions, some being known to be able to take fire spontaneously. This is plain scarry. Imagine what happends if this takes place in an already finished shell? So the question of safety remains, vs the benefices of a really good green.

There are two things I'd like to get answers for:

1. Is it feasable to obtain BC from the electrolysis of BaCl2 using Ti/MMO electrodes. Did somebody do it?
2. Is it really that sensitive, and if so what are the factors making it so (obviously no sulphur/sulphides etc, but there may be others)


I mention I have access to Ba nitrate/KP/AP/MgAl etc. but the green sucks compared to BC (barium chlorate).

[Potassium chlorate]

It's very powerful and sensitive, yes, but with shellac I think there would be no risk for spontaneous ignition.

I'm also in love with this chemical. The colour it produces is like magic.

Edited by Pyroswede, 28 October 2009 - 07:11 PM.

[Arthur Brown]

BaCl will electrolyse to chlorate with MMO and stainless cathode, BUT due to adverse reactions in the cathode zone the cathode has to be rotated or the Ba forms insoluble by products and precipitates out.

Best is to use KCl or NaCl and electrolyse to saturation of chlorate then add BaCl to ppt out BaClO3.

Also whatever chemistry you will need to put lots of amps in for a very long time to make much product.
Someone pushed 50 amps for 150 Hours to get a good output, now that is a really good power supply.

Added; 7.1KWhr per kilo is quoted as real experimental current efficiency, possibly no more than 50% of stoichemetric figure

Edited by Arthur Brown, 28 October 2009 - 08:09 PM.

[a_bab]

I gotta try BC it with colophonium. It should work similar to shelac I hope.

The thing is, the color made by BC is just fantastic. Better then anything for sure.

[Potassium chlorate]

I gotta try BC it with colophonium. It should work similar to shelac I hope.

The thing is, the color made by BC is just fantastic. Better then anything for sure.

Is it hard to get shellac in your country? Here we just buy it in any hardware store.

[a_bab]

No, it isn't. But the price is close to 30 bucks/kg (quite a rip off).
On the other hand colophonium is like 5-10 bucks/kg.

Certainly my precious kilo of shellac would only be used for THE green stars. If colophonium doesn't work, that is.

Now, on the instability of the BC compos: there are many accounts in the literature, all saying that BC compositions are more sensitive then potassium chlorate ones. But, there are many other things in such a composition, like barium nitrate. Also, it is stressed that in the sunlight sometimes spontaneous ignition can occur. This makes lots of sense, as BC is less stable than potassium chlorate, and the UV light certainly decomposes it to things like chlorine dioxide, that would ignite/heat anything organic. Think sulphuric acid dripped onto a sugar/potassium chlorate mix to get the idea.

There is another story about some lances that self ignited in the past. They concluded that BC was the cause. But only God knows what else they may had in the composition, as lances tend to be slowed down, and this means lots of fiddling with the formula. Not talking about the purity of the chems, known to be not very good those days.

Yet another story states about some barrel of BC, that was heavily rusted and when opened there were specs of rust in a yellow, chlorine stinking BC. That means decomposion, and if something combustible was mixed in, it could have meant ignitionn. But, what were the conditions that lead to this story? Since the rust was IN the barrel, it could have been heat, and the resulted chlorine fumes corroded the barrel from the inside.

I am getting more confident now that a simple verified formula like BC/shellac may indeed be safe enough. The question of a safe priming (although I'm sure none is needed)/breaking charge remains.

Edited by a_bab, 29 October 2009 - 09:15 AM.

[Potassium chlorate]

The breaking charge has to be rather weak, otherwise the stars will detonate instead of burning due to the high percentage of chlorate. Potassium perchlorate/charcoal perhaps. Or even sulfurless BP, if the shell is a big one.

[sir steve]

[quote name='a_bab' date='29 October 2009 - 08:10 AM' timestamp='1256803850' post='61003']
No, it isn't. But the price is close to 30 bucks/kg (quite a rip off).
On the other hand colophonium is like 5-10 bucks/kg.

Dont waste your bucks on colophonium gum . Pay the money and get shellac. red gum will do.
Also buy Barium Chlorate from a good supplier. The best comes from Sweden. It is my
favourite chemical. That said some people are alergic to it.

Steve.

[Mumbles]

I've never heard of anyone, especially anyone with extensive chlorate experience, ever say chlorate stars could detonate from any normal burst, even some flash bags. Impacting the ground of excessive lift is another story though.

[Potassium chlorate]

I've never heard of anyone, especially anyone with extensive chlorate experience, ever say chlorate stars could detonate from any normal burst, even some flash bags. Impacting the ground of excessive lift is another story though.

But did they use 90% bariumchlorate? It's originally a Bengal fire formula, not a star formula.

[Mumbles]

That formula, or very similar ones, is given in every old firework book I've ever seen. Weingart, Kentish, etc. I've talked with several people who have used these stars and they've never had issue. Obviously sulfur is rigorously excluded. The shells were all cans shells by the way if that makes a difference. Yes, they are pretty sensitive, but it can be done. I saw one reference in Weingart that was approximately as sensitive as a chlorate/gallic acid whistle. Never made them so I don't know off hand what that corresponds to.

4 or 5 parts of BaCO3 will do well to desensitize it.

There's one exhibition green given in weingart that specifically mentions no shells. It contains Ba Chlorate, calomel (a known sensitizer), and picric acid. Now that's a recipe for hole in the earth.

[Potassium chlorate]

My shell was a 2" hemisphere shell and I used sulfurless gunpowder (you can buy it without a license here) as a burst instead of coated rice hulls. The stars were pretty big for such a small shell, though, 10 mm pumped.

[CCH Concepts]

That formula, or very similar ones, is given in every old firework book I've ever seen. Weingart, Kentish, etc. I've talked with several people who have used these stars and they've never had issue. Obviously sulfur is rigorously excluded. The shells were all cans shells by the way if that makes a difference. Yes, they are pretty sensitive, but it can be done. I saw one reference in Weingart that was approximately as sensitive as a chlorate/gallic acid whistle. Never made them so I don't know off hand what that corresponds to.

4 or 5 parts of BaCO3 will do well to desensitize it.

There's one exhibition green given in weingart that specifically mentions no shells. It contains Ba Chlorate, calomel (a known sensitizer), and picric acid. Now that's a recipe for hole in the earth.

from what i gather isnt picric acid a HE?

[Potassium chlorate]

from what i gather isnt picric acid a HE?

It is, actually even a bit more powerful than TNT, but it was still used in some older formulas.

[CCH Concepts]

i think i remember reading it was used in warheads on torpedo's and artillery shells. its impact sensitive. what use did it have in fireworks?