Very small salute inserts

[dangerousamateur]

Hi

 

I'm about to make some small inserts for 8mm bottle rockets.

 

They will contain about 200-300mg flash in rather thin 6mm tubes. I have to keep the weight down, so I cannot provide very much confinement. Break will be very soft of course.

 

To make sure I get sharp cracks instead of white gogetters, what kind of measures can I take to make my flash more "detonation" eager?

 

Compared to 70/30, will a mixture with sulphur like 64 23 13 or the classic M80 mix with antimon trisulfide be more suitable? Since they are more sensitive, I suspect them to work better in very small amounts.

 

How about magnesium based stuff?

 

 

I cannot test these things very often here for obvious reasons, so It would be helpful if you can give me some starting point

[Algenco]

I add 10% sulfur to the standard 70/30, nearly the same as Shimzu Thunder

 

Never had it fail to pop har in small amounts with minimal confinement

[Potassiumchlorate]

I made some 64:23:13 yesterday. I always diaper mix on newspaper and then burn the newspaper. Although there were only small amounts, at most a few hundred mg, left on the paper, it made several small "pops" totally unconfined. I think it will do very well for you. In commercial bottle rockets they use 70:30 and not even with German Dark but with bright flake Al Edited December 1, 2012 by Potassiumchlorate

[Seymour]

2-300mg of flash is still plenty, in my opinion, for 70/30 to go bang satisfactorily with rather flimsy and pathetic confinement.

 

I have had 500mg go off with a sharp bang encased in a tube of tissue paper, one layer thick (one third two layers, overlap) with open ends. This was just well mixed 70/30 with good Aluminium, and good mixing (pre sieving the KClO4 -120 mesh being notable) . I bought the Al as Indian flake from the US Ebay. It seemed genuine, very dark, more so than Ekhart 5413, like BP fresh from the mill, with the odd twinkle from pesky macroscopic bits that did not seem to alter the performance.

 

I don't see why the bare minimum confinement required for holding the flash in place, and preventing them from going of prematurely in the burst (even if gentle) won't be sufficient... assuming you are using the nicer flash grade Aluminiums. If you are using less reactive Aluminium, upgrading your metal will certainly be safer than adding sulfur, though I will certainly not disagree that it is also an effective option.

 

As you get really small, spicing your flash up with Sulfur, sulfides, catalysts and/or more reactive metals will be required to get good results, especially with small amounts, but with 200mg + I don't personally think you are there yet. Still, I said required. I know some people are rather fond of some of those special vitamin blends, and not just for small things.

 

I typically also diaper on newspaper, screening the powders separately on to the paper beforehand. More and more though I screen the stuff two or three times -60 instead of diapering. With the separate per-screening of the chemicals beforehand (important whatever method you use next in my opinion) it just flows through so nice and purty (in half kilo - 1kg batches).

 

Still, when I made up 20kg I got all superstitious and diapered it, on a bigger bit of paper than news paper of course. This was with 70/30 though, and is also a little off topic.

 

I always diaper mix on newspaper and then burn the newspaper.

 

Yes. It should be burned as soon as possible, and in a safe manner. It should be assumed that it will upon, or some time after being ignited, be consumed in a small explosion. As much as this is obvious, I have been given a very nasty bite and rude awakening from a piece of flash diapering paper that got away. Though the risks are as I said obvious, and this inflates the shame I have for it, it still is a good reminder for us all for me to stress.

Edited December 2, 2012 by Seymour

[Arthur]

70/30 is the fastest mix I use, however even this can be adjusted by using fine or even finer perc! With milled fine perc 100mg in an open heap (that's a pile the size of a match head!) will go bang very effectively. If you can feel grain in the perc then mill it or just sieve out the fines for use.

[Potassiumchlorate]

I use 2:1 when excluding sulfur. Stochiometrically it should be 65.8% potassium perchlorate and 34.2% aluminium.

 

70:30 is almost stochiometrical when using potassium chlorate instead, but surprisingly I never found that to be more powerful.

[Mumbles]

I suspect you'll have more issues with getting the inserts to stay together than providing enough confinement. I don't have any doubts that 2-300 mg will salute. I've often seen antimony trisulfide being recommended in small salutes to make them "sharper". Generally in proportions of 7:3:1 or 8:3:1 Perc:Dark Al:Sb2S3.

[pyrojig]

If one is experienced (many years of practice under the belt) they could use a more reactive metal to obtain a flash capable of popping in milligram amounts. I have found that fine magnal is very reactive and capable of self confining in 1/4-1/2g piles. Even smaller if the magnal is 400-600mesh. This flash is perfect for small applications, but more dangerous to the amateur who has little to no experience with flash. Im not sure of the shelf life of this mix, but assuming the Chinese use this metal extensively, I figure it has to last several years w/o degrading.

[Potassiumchlorate]

How dangerous will the flash become with antimony trisulfide? Instinctively it feels like it will be sharper than when "laced" with sulfur.

[AirCowPeacock]

Shimizus tables suggest, as far as friction and impact goes, antimony trisulfide will not increase it's sensitivity as much as with sulfur.

[spitfire]

My question is, if 70/30 doesn't do the (pyrotechnic) trick for you, what on earth are you looking for...? A huge bang from a 10 gram bottle rocket? Your own safety might come in to play. There might be a theoretically better flash, but is it worth all the trouble for just bottle rockets.. If the bottle rockets are for your kids/young relatives.... they won't notice any difference. Make them happy with a safe mix and rockets that fly and go bang. They'll be happy anyway. Just my 2 cents for your safety.

[dangerousamateur]

what on earth are you looking for...?

As I wrote just a little report, an XXL dragon egg, nothing more.

 

70/30 reported extremely well in a little test today, and it also survived the "bag" header. I used dark Al.

So you where right, no further tuning is necessary.

[Eduardo]

Any one tryed this Allan Yates' composition?

 

by Allan Yates' site...

 

Name: Zinc "Flash"

Source: Alan Yates

 

Composition:

 

63.00% Zinc (dust)

32.00% Potassium Nitrate

5.00% Sulfur

Edited December 18, 2012 by Eduardo

[pyrojig]

This sounds more like RP. Not flash. If flash Im sure it would be quite slow.

[AirCowPeacock]

I think it would make a more effective flash then 5:3:2 KN:Al:S flash.

[Mumbles]

That's not saying a lot.

[AirCowPeacock]

True, but I would still consider slow flash, flash powder, and I certainly wouldn't try to use it as rocket propellant.

[Mumbles]

I would consider whistle mix to be more powerful than slow flash, and well.....

 

Also, for what it's worth, I've been told by Steve LaDuke that you can make a rocket from straight 70/30 with enough compression.

[AirCowPeacock]

Whistle is probably 'more powerful', but in my experience it has a lower burn rate exponant (in a burnrate pressure relationship.) I would think you could make a rocket from it, but I wouldn't. Partly because I know I would need double wall thickness just so the casing doesn't burn up.