18 replies to this topic

[Creepin_pyro]

I have recently tried combining flash products with my usual technique for producing mines/roman candles, with some surprisingly worthwhile ( if a tad expensive ) results.

For example, I took a single 8mm white star, a small circle of flash paper, and some electric sparkle additive (comp unknown) with a small amount of copper oxide added. Placing the star in the centre of the paper, powder was added to surround the star, leaving just enough free paper to twist or glue the end to keep the star together. When launched, the stars leave the tube emmiting bright blue sparkles in quite a dense cloud, then countinue as normal white stars.

I have also experimented with using flash cotton instead of coarse grained BP to launch these things, with great success. I've reached a good 20-30 feet in the air with a lovely "pfoot" sound from the cotton.

I realise there are more conventional ways of producing colour changing stars, but I have little equipment, and my star rolling is still in the experimental stage.

Thought this might be of interest, if not of much practical use. Hope it sits well in this forum, as flash products are used mostly in theatre/film SFX.

[adamw]

Thanks for the post and welcome. I'm gobsmacked someone has actually done it right first time! Sensible post, and in the right area! Woohoo!

The use of flash cotton etc as a lifting medium has been dabbled with before, but as you said, would probably work out more expensive. The safety of such a method also has to be established - ie chemical compatibility. In essence what you have with flashpaper is nitric acid. Although in the manufacture stage it should have been rigerously cleaned to remove any free acid, the fact that some may remain or may leech out or form from decomposition of the paper should not be ruled out.

When you say "Placing the star in the centre of the paper, powder was added to surround the star" I assume you mean the sparkle additive, yes?

I am interested to know how pure and bright the blue effect produced was. Sparkle additive generally contains 'orbron' type bright aluminum and magnesium. Wether it contains a chlorine donor which may have enhanced the blue colour I do not know.

What brand is the additive? PyroPak? I have some of this somewhere so may dig it out and try.

Let us know how you get on.

[lord_dranack]

I was looking on the new scientist archives the other day and found some interesting information on research to replace gunpowder in fireworks with nitrocellulose, or a mixture of KCLO4 and a resin.

The reason given for using NC was as it is cleaner burning and allowed less salts/chlorine donors to be used so was more environmentaly friendly.

It also mentioned a giant set of computer controlled mortars developed by disney that uses compressed air to give pinpoint accuracy

[adamw]

...but over in reality land...

Blackpowder has been used for thousands of years. To be honest, I don't see it ever being replaced. Stay with me forever! The smell would never be the same!

[Yugen-biki]

I have read a small number of articles on replaceing BP. Geoex (...?) were the closest to BP.
In the end BP can?t allways be replaced, and manely due to burnings caracteristics but also friction and shock problems and price.

I tend to make as few comps as possible to ceep it simple and be abel to reproduce the same comp after a period time.
With 9 differens comps you can make most off the effects out there!

Edited by Yugen-biki, 03 February 2004 - 09:47 AM.

[Creepin_pyro]

I did think briefly about seperating flash powder from any contaminates with flash cotton, to add to mines. I then remembered the procedure to make the cotton involved Nitric and Sulphuric acids, which might leech out if not prepared/washed properly (don't suppose anyone has come across this before?).

Anyway, prepared some lovely flash cotton recently. Doesn't compare to the real stuff, as it leaves some ash and burns slightly slower, but created a less dense flame with a kind of arc-ing deep orange sparkliness...

Should have recieved chem order today, so I can stop playing around with the Cat. 1 indoor stuff.

[adamw]

Be careful with nitration. If you must do it, which I dont recommend (the use of concentrated acids for one), make sure you keep the damn stuff cool! A runaway nitration wouldnt be a nice thing...

[Stuart]

Lots of lovely nitrogen oxides

[miniskinny]

I was wondering, could someone tell me how to make flash cotton for propulsion?

[Rhodri]

I was wondering, could someone tell me how to make flash cotton for propulsion?

 

Hi Miniskinny

Technically flash cotton (cellulose nitrate) is not used in pyro.

It's also classed as HE and as such we cannot describe its manufacture here.

If you are interested any decent book (A level +) will explain the process.

Nitrating organics is not a pleasant task either.....

[Creepin_pyro]

Making flash cotton is not something you should try at home - also its hard to achive professional results. You shouldn't have any trouble buying the stuff - search for stage pyrotechnics.

What kind of propulsion were you thinking of?

[miniskinny]

deleted.

Edited by miniskinny, 12 March 2005 - 07:54 AM.

[adamw]

You propel SHELLS, not MORTARS

[miniskinny]

Heh, I guess that's sort of American of me to get those mixed up

[italteen3]

Heh, I guess that's sort of American of me to get those mixed up?

 

Yes, a common mix up started by the illegal selling of Class B fireworks many years ago. Dont worry I used to think the same thing at one point too .

I dont see flash cotton replacing BP for lifting. I would first elaborate more on how you feel BP can cause problems then someone could help you out. Im having the same issue you are with lift powder, I think it will just take time and a precise practice.(and getting my monster mill started)

Edited by italteen3, 28 August 2004 - 04:54 AM.