273 replies to this topic

[NorCalPyro]

Thanks for the beta gents. Very helpful. I appreciate the words of caution.

Any advice on best procedures for pressing? Does pressing and a blast shield go hand in hand for most folks?

[Mumbles]

Just so you know, I have never in the history of pyrotechnics heard of a fountain being dead pressed. Deadpressing is more a term associated with high explosives, and not really applicable here. The equivalent of ramming/pressing too much in pyro is breaking the tube/support sleeve. The speed with excessive pressure will surely slow, but absolutely not to the point where it becomes useless or have diminished functionality really.

[GZ22]

Yes, perhaps 'dead pressing' is the wrong term to use (from my HE training) - just couldn't think of an appropriate alternative for pyro. And agreed - you're likely to split the tube with excessive force. Though I did once make a simple fountain many years ago and when ignited, it just burned very erratically in spits and spurts because I'd pressed it too hard.

[MDH]

Just thought I'd share:

Black Powder, 3-6
Sulfur, 0.6-1.0
Sodium Chloride, finely powdered, 1
Dark Pyro Aluminum, 1

Tonight is one of my testing nights and I found this composition was quite lively, although with a nozzle it became drossy and wouldn't work. Tested inside 8mm with 4mm thickness (home made of course) and about 2 and a half inches long, open ended, no nozzle.

Probably could use more black powder if anyone is willing to experiment

With minimal oxidation and a binder I think it'd make nice sparklers but with more black powder (thus more oxidation) it becomes a nice fountain.

Makes a pleasant sound.

Edited by MDH, 23 December 2007 - 07:53 AM.

[portfire]

The only formulas I dont seem to try are fountain comps, so thought It's about time I did. The formula is Lancasters-D, from 'Fireworks, Principles and Practice'

KNO3-27
S-14
C 40-100#-9
Meal-40
Ti 40#-10

Here's a few build pics


Tubes were 110mm long, 15mmID, 4mm wall, and a choke of 6mm.

Video
http://www.pyrobin.c...an fountain.mpg

The tubes were only half full with comp as I was testing some new fountain tooling, and the comp it's self, thats why the burn-time is short, but all in all it's a great simple comp, and recommend trying it

[pudi.dk]

Nice fountains, this is Degn, Silver Gerbe #11

Potassium Nitrate 6
Titanium, sponge, 18-30 mesh 3
Charcoal Airfloat 1
Sulfur 1


http://www.pyrobin.c...tifountains.wmv

[Bonny]

Nice fountains, this is Degn, Silver Gerbe #11

Potassium Nitrate 6
Titanium, sponge, 18-30 mesh 3
Charcoal Airfloat 1
Sulfur 1


http://www.pyrobin.c...tifountains.wmv

Those look really nice pudi. Care to share some details?... tube size, choke size. Did you mill the comp then add Ti?

[pudi.dk]

Those look really nice pudi. Care to share some details?... tube size, choke size. Did you mill the comp then add Ti?

22 mm tubes, around 38 grams of composition in each one IIRC (same weight of composition measured out for better timing).
Nozzle is 1/3 and no core.

Chemicals were just screened together.

Edited by pudi.dk, 24 June 2008 - 08:16 PM.

[Bonny]

22 mm tubes, around 38 grams of composition in each one IIRC (same weight of composition measured out for better timing).
Nozzle is 1/3 and no core.

Chemicals were just screened together.

I'm assuming they were pressed, but did you just hand press or use a clamp/jack?

[pudi.dk]

I used a 10 ton hydraulic jack, although I'm sure less would do it just fine.
Tooling was something I just improvised, low quality pine tools which broke, but were only for these specific ones hehe.

[MDH]

Well, today I tried several fountain formulas from a consumer fireworks company who I can not name, with the compositions being listed as "simple". I'm guessing this is where they make their money ...

Here's one.

Fountain Base #2
Potassium Nitrate, 6
Mixed Pine Charcoal, 3
Sulfur, 1
Preparation: at factories it is screened together through a double-layer -20 mesh screen.
my notes: I did test this. It burns uncleanly with a lot of leftover nitrate dross and smoke. My guess is that they have a specific kind of casing that they use for fountains containing this composition that allows it to lift the dross and react it with larger pieces of charcoal and sulfur. In the open it isn't very impressive.

[seymour]

That mix is exactly the same as the humble "six-three-one" standard core burning rocket fuel. When I've burned that mix there has always been plenty of charcoal sparks, but dross has been lacking from the products of combustion, in any significant quantity anyway.

Perhaps it's name "Fountain base" implies that it is intended to have micro-stars in it?

I have used it in fountains on a number of occasions. When cored the plume is rich, moderately high in height, and very lively. When used in an end burning system the plume is very small for such a sized device yet the other qualities remain. Light weight spark producing substances, especially charcoal, do not fly far.

I have used it with both ball milled, and relatively coarse screened-together compositions. The coarser mix has longer lasting, slightly higher reaching sparks, while the ball milled mix is a more unique, feathery, yet smaller result.

[MDH]

What I've always been curious about is what kind of compositions the companies use in these small fountains which are often only 3" tall and 2/4" ID and yet last up to 30 seconds... They must really optimize their compositions to yield such results.

[pyrotechnist]

I wonder that to and when I always check out the tubes afterwards I rarely see any clogging of the choke from dross or see a tube burn through. Could they use excess charcoal etc for the longer lasting plume?

Edited by pyrotechnist, 21 August 2008 - 06:09 AM.

[JackFlash]

Please post all fountain formulas here.

Hi there people.
I hope I am doing things here in the correct order and am not breaching any forum etiquette here but hi from new member here.

Just to say I have been researching pyro for several years as a half hearted/interested/curious reader but have for the last 6 months being researching and accumulating reagents more seriously.

Just to comment after 6 months of research and accumulation I have finally made my first gerb, I think. You old lags may tell me I made something different.

My mix was a 24 4 4 10 mix of KNO3 C S metal.

I used 300 mesh Al.

Wanted to start non lethal. (PS I know that a lot of the dangers are exaggerated but still existant and stupidity and carelessness are nearly always the cause of all accidents, pyro or otherwise.)

Anyway I primed through the ignition with black powder due to visco not having arrived yet (I realise improvisation and impatience probably another major factor in pyro mishaps) but this seemed very feasible in such a safeish compound.

Ignited with a match head the prime compound which slow burnt until the bore hole and then i got a mini fountain which I would have been quite happy with, this being my first ever gerb and this was about 10" high.

Five seconds later I got an almighty roar and a fifteen foot spray of white sparks came out for about 15secs until the side blew out.

I am buzzing at the moment as all problems are easily understood and thicker walls are needed and obviously visco.

The fountain rivalled the dearest fountains available on the market and I am so happy to have had such a success.

I know this seems like small beer to some of you old hands but the buzz of your first success must still be lurking there in your pyro jaded memorybanks.

Love you all and stay lucky.

PS. I used a
3/4" X 3 1/2" tube 1/16" wall.
6mm choke.
1/2"-3/4" bentonite plugs either end.

Edited by JackFlash, 10 May 2009 - 09:21 PM.