Jump to content


Member Since 18 May 2005
Offline Last Active Jul 05 2019 01:06 PM

Posts I've Made

In Topic: Fireworks from Malta

20 August 2012 - 02:34 PM

Maltese fireworks are the best in the world period.

It has been discussed many times before; the level achieved by their cyl shells is unique in the world.
I'm also amazed that the round shells can rival the japonese ones, all learned by these wonderfull people in like 10-15 years.

This is all given by free work, many "firework schools" competing + secrets.

In Topic: Two Arrested

13 May 2012 - 08:16 AM

Vic, can I have a link about that case please?

In Topic: Mortar tube life span project?

31 January 2012 - 12:07 PM

Depending on the cardboard quality, 10-100 shells are said to be the max recomended number for a cardboard mortar. As the time passes, some of the paper unwraps inside. This could be a problem (there's a case of a truck full of cardboard mortars, that caught fire because of a glowing ember + air draft cased by the truck moving)

Better invest in some HDPE mortars as they will last much longer.

In Topic: Micro thrust motor

05 December 2011 - 04:11 PM

You are welcome Dragonsinger.

From the discussion link I posted you can see that the Rapier uses a ammonium perchlorate/zinc kind of compo, that would burn with high temperatures. Please do read it as it clears down many questions you may have. The cardboard casing is designed such that it could whitstand the temperature during the burning time.

In Topic: Micro thrust motor

05 December 2011 - 06:51 AM

Your problem is that the fuel is not only supposed to burn slowly, but also with a low temp. Jetex barely went over 450 degrees C I guess.
Rocket fuels are of several kinds, but the usual oxidizer/fuel mixtures burn past 1000 degrees C and the use of a metal case (as in Jetex) is strictly forbidden due to a serios explosion hazard.

"Jetex" type engines used guanidine nitrate as a fuel. I really doubt you'd be able to get your hands on it, as it's really an elusive chemical and a HE, so you're going to raise more then some eyebrows. However it can be synthesized with the proper determination as the precursors are easy to find.

As an alternative you can probably use nitrocelulose. There are different grades available, and it's used in the paint industry. A plastic called "celluloid", still in use can also be seen as a weak, slow rocket fuel in my childhood rocketry experience. Ping pong balls are made of it (althogh I have seen some that are not). A "good" ping pong ball can be easily recognised as being made of celluloid by scratching it with the finger nail; a mentholated smell is then detected (it's camphor, as celluloid is a mixture of camphor and nitrocellulose).

An interesting read you may know about: http://www.jetex.org...?num=1254520818