7 replies to this topic

[aapua]

Hi everyone again,

just to share 2 ideas I finally tested few days ago.

The first one is about the method to get the burst charge. Instead of coating rice or whatever I used swab or some other type of soft foam plastic. Cut it into pieces of 5x5x5 mm.This time I used regular mealed BP (75/10/15) with +5% of Dextrin and +5% of DarkPyro Aluminium. I added water to get nice "soup" and put the swab into it. The foam takes pretty nicely the mixture in it and dries, making pretty hard pieces. The performance wasn't too good, though. It was too slow. Probably it's better to use perc/s/c micture with some extra Al. But this is my next experiment, I wasn't in my lab when making this, and I hadn't perc there. Anyway, this method helps to make the burst charge very easily and quickly. The disadvantage is that in bigger shells you have to use some hard neutral fillings, the foam is physically not hard enough.

The second idea is to use a very special epoxy-glue in the mixtures. The glue I got is Wessex Resin's CASCOPHEN RS 12 A with resin hardener RXS 22 A. The good point is that the stars dry within 24 hours, the mixtures with this glue are very stable, and you can prime stars before they dry. Though, because of high content of different elements it was pretty hard to get good green and blue, with red there was no problem.

For red I used:

KClO4 - 50%
Sr(NO3)2 - 25%
Hexamine - 10%
Al DarkPyro or Mg - 2%
Resin RS12A - 10%
Resin hardener RXS22A - 3%

After drying very hard, ignites easily and burns quite a long time.

Any comments are more than welcome.

Regards,

Aapua

[aapua]

It depends on the time you keep the material in the "soup". When the time is short enough, the mixture stays only in the outer pores and doesn't go in. So it doesn't form a "star". Again, there are huge variety of different materials, I chose the one with pretty small pores. The result is just coated pieces.

[fishy1]

1) "It was too slow"

Pretty much says it all about idea no1. perc/c/s is also a bit of a waste of chems. It doesn't take me long to make up a couple of pints of rice crispy filler.

2) An interesting idea, but you can't get blues or greens and the glue probably isn't cheap. Could you thin in out with acetone or something? I don't know alot about resins but I'm curious.

[Mortartube]

Your use of cascophen resorcinol resin is how the little square stars were made for this rocket back in the late 1960's or early 1970's. These ones are red by the way.

http://www.pyrosocie...?showtopic=2210

[aapua]

Well, about the price - depends what is expensive and what's cheap. Blue and green - as I said it just took some days of playing, but I got these. For the blue I used ammonium perc as the main oxidizer, plus some CuO and Cu acetate, again with hexamine. By adding some Barium perchlorate the colour gets deeper. Green bases on only barium perchlorate or its mixture with AP, I can put here the compositions tomorrow, because I'm home now.

Note. The cheapest price is not my purpose - as cheap as the chinese fireworks is it never will be anyway, what I try to do, is to get colours even better, the effects last longer etc.

You can add both acetone or better methylated spirt to the glue.

Mortartube - do you know what was the company made these rockets? These flat stars are very interesting.

Edited by aapua, 21 November 2006 - 06:41 PM.

[aapua]

To mostly Shrubsole and fishy1.

I've done some research works with the "idea no. 1". I guess that the slow results with the 1st attempt were simply caused by bad mixing of chemicals.

KClO4 70, C 18, S 12 + 5-10% AlDarkPyro + 5% Dextrin works very well.

As i already mentioned there a huge varieties of foams. As I would say the best results are with the ones with "open pores". The point is that it sucks in all the paste or soup, after drying it actually gets back its old form - its a foam again. It is clearly seen when you cut the dry pieces into thin slices - it has like it was, foam, the dried mixture stays as a thin layer everywhere in it. So, instead of forming a solid star, it actually has a huge reaction surface, and the actual weight of burst charge will be therefore much less.

Anyway, just one alternative possibility in my mind.

[Mortartube]

Sorry, I've just caught up with this thread again. The rockets and stars were made by Brocks at their factory in Sanqhuar, Scotland.