823 replies to this topic

[digger]

No problem. Questions ultimately lead to understanding.

To underline it. Most flash mixes (not all) are considered to be negative explosives. This just means that the final reaction products are denser and occupy less space than the reactants. This does not mean that this is so during the reaction (bang).

The article does not state that negative explosives are safer. It just says that the one discussed is safer than standard flash which is also a negative explosive.

[CCH Concepts]

if the final reaction products as gasous wouldnt they occupy more volume?

[cooperman435]

The final reaction products are solids, but during the change stage (bang) they are super heated so are in the gaseous stage until cooled down.


One of the reasons I made my earlier comment is that you seem to make judgements based on information that isnt there CCH, prime example being that because one composition is named as safer than another you take this to mean a whole group of compositions are safe. My comment still stands from months ago, patience is virtue, if you dont understand at first keep reading and read more literature on the subject dont base your judgement on one article.

Edited by cooperman435, 28 April 2010 - 12:04 PM.

[CCH Concepts]

that was exactly my reason for posting, i posted a previous topic on the subject stating i hadnt found much info on it and did anyone have any experience with it. simply because i dont understand it and wanted to know more.

i would like to say, unlike when i first joined the fourum, being that i dont know about negitive explosives i havnt tried the aformentioned formulie.

when i first joined the forum, my first instinct would have been to find out through experiementation, now i read and ask questions as my first instinct. i have learnt from my mistakes and from advice given, both from yourself and others.

one example is i have abbandoned my paintball venture until i am satisfied i have relevent experience and can get licenced.
with what i know now, trying to use flash with it was idiotic, just took time and reading for me to see why your advice was correct, but at the time i did hede you advice and stopped, even though i didnt fully understand why the advice was correct.

[Potassium chlorate]

I don't know why there is this endless preoccupation with flash. It plays only a small part in fireworks albeit an important one a times, but nothing like the gratuitous attention it gets on the forum.
I am not anti flash if used wisely it's just people seem to be overly attracted by it I suppose it's to do with the power and the dangers associated at the end of the day it is a blunt instrument.
And with regards to HE, any posts about it or bordering on the subject in any way should be deleted

Flash makes a very good break for the smallest shells, like 1" and 2". It's hard to get a decent break with anything else I think, maybe with the exception for whistle mix. Have actually not tried that yet. If you use flash as a break, you can fill the shell completely with stars and just add about 1/10 of the star weight in flash in the small space between the stars. And of course the heat the flash produces also makes sure that the stars ignite very well.

[Atom Fireworks]

Flash makes a very good break for the smallest shells, like 1" and 2". It's hard to get a decent break with anything else I think, maybe with the exception for whistle mix. Have actually not tried that yet. If you use flash as a break, you can fill the shell completely with stars and just add about 1/10 of the star weight in flash in the small space between the stars. And of course the heat the flash produces also makes sure that the stars ignite very well.

Ime not sure what flash mix you use but i wouldnt use just flash as burst it would be too violent maybe add abit to aid in the burst but thats about it.
And also as a side note i really wouldnt let flash become into contact with stars, especially if they contain sulfur. Ime no chemest and not extensivly experienced but flash around stars sounds really dangerous. I stand to be corrected if i am wrong.

[seymour]

I like to sprinkle BP in the gaps between the stars, and then just add a few grams of flash. Flash may be too violent for some people in these small units, either because they have stars which can not cope, or flash which is too brisant, but it does work for other people. Definitely you should be aware that over-breaking is a possibility when using flash, however, it works well without ill effects more often than many people think.

As for contact between sulfur containing stars (or burst) and a flash powder, in most cases I do not think that that would be of significant concern. I say 'most cases' because it does depend on the formula. I would like to think that it will always be a nitrate or pechlorate flash, but some people do insist on using chlorate for flash, though I suspect that there are not many forum regulars who do this.

Yes, sulfur does sensitise Potassium perchlorate more than most fuels, but not to the extent that it has been definitively catagorised as an incompatable mix, indeed, formulas with the two in them are widely used, and often highly regarded (KP burst charge, Ruby red star formula, many blues).

Because S sensitises KP, and because it is unneccisary, I will not add sulfur to my KP/Al flash powder, but also, I will keep adding it directly to black powder burst as a loose powder when boosting shells.

[Vic]

As I said I am not anti flash but you can use kp on your rice hulls or on whatever carrier you choose, along with a whistle booster as long as your shells are well pasted. But you are not going to get the hard breaks that you get with a flash booster especially on smaller shells. Flash bags are a good way to contain you flash instead of just dumping it in. There are many that coat their rice hulls before hand with booster.

[pyrotechnist]

what about coating rice hulls in flash?

[Potassium chlorate]

what about coating rice hulls in flash?

I think you all complicate things. In a small shell, up to 2" or maybe 3", but absolutely not bigger than that, the best way to make it is to fill both hemis with stars and then add 1/10 standard flash by weight. You will get many stars despite the shell being small and you will get a strong but not too strong break.

For 4" and bigger BP, potassium perchlorate based powder or H3 on rice hulls, corn cob hulls etc. or granulated will be perfectly alright.

Edited by Pyroswede, 01 May 2010 - 07:26 AM.

[PyroCreationZ]

Flash coated rice hulls are actually being used by the Chinese but only in smaller shells (up to 2.5" I believe) or bombettes (in cakes).
Like Pyroswede says, for bigger shells, BP coated hulls or whatever should be fine.
And adding just a little bit of flash as a booster can help.

[Potassium chlorate]

I was experimenting with green colours, and for that purpose I bought some barium sulfate. Of course I had to test a small amount of flash made with it:

potassium perchlorate 33
barium sulfate 33
magnesium 34

This is about as powerful as potassium perchlorate and magnesium alone and cheaper.

You can use barium nitrate instead, but I actually think the sulfate makes it a little more powerful.

[digger]

I was experimenting with green colours, and for that purpose I bought some barium sulfate. Of course I had to test a small amount of flash made with it:

potassium perchlorate 33
barium sulfate 33
magnesium 34

This is about as powerful as potassium perchlorate and magnesium alone and cheaper.

You can use barium nitrate instead, but I actually think the sulfate makes it a little more powerful.

Interesting stuff there Pyroswede. Do you have any video of your experimentation with these compositions.

D

[Potassium chlorate]

Interesting stuff there Pyroswede. Do you have any video of your experimentation with these compositions.

D

Nope, not yet. I actually haven't posted any vids with flash yet, except the vids of two of my 2" shells, where flash is used as a break, and that is standard 70:30 potassium perchlorate/German Black.

You might also make your flash stronger (though more expensive) by using a 1:1 mix of magnesium and either potassium chlorate or potassium perchlorate. They're over-fueled, but the magnesium takes atmospheric oxygen, and it does so rapidly, especially with really fine magnesium. The potassium perchlorate formula is often called "Shimizu Magnesium".

[Vic]

???If you know how to make BP, I see no reason to use flash. Maybe cause I am from the states where possession of more than 50 mg can put you into jail for 6 years, be handed a felony charge which takes away your gun rughts I have learned how to make a BP that is able to break shells of any size. Reading some of these folmulas here scares me. Just take some potassium clorate, and sulfur and thinly spread it upon a smoth hard surface. Then hit it with a hammer. BOOM. Goes to show you the danger.Well made bP corned into a lift powder is a fine substitue for breaking any shell, and a thousand times safer! OMG!!! potassium perch. mixed with fine magnisium? Talk of playing with fire!What it is, is "overkill. I never had any trouble breaking any size shell with my BP.Wish all of you luck. Very good luck. Not smart playing with such foemulas.

I see you are back again Anyka