273 replies to this topic

[Richard H]

Sounds excellent.

[MDH]

With thicker walls that fountain would have exploded with a very loud bang. Maybe you should make your nozzle hole a bit wider. Losing a few feet of height, at 15 feet, shouldn't be too much of a problem.

You might also want to try a non-oxidizing fire retardant in your tube.

[dr thrust]

hmm, a great story of your first gerb and it sounds like you've gone about it the right way by researching, then some more researching...
Agreed open up your nozzle to half the tube id, 8-9mm, although a really good quality thick walled tube should be able to withstand the pressure, as core burner rocket motor's have to deal with a great deal more and survive saying that though ive made great fountains with no choke at-all you dont get the height but a great spread of effect and im glad you got a buzz out of it, i got a buzz just reading it!

[JackFlash]

Glad to get a response. Wasn't sure whether I was too novice.

I have always loved pyro.

Costs me a bleeding fortune every Nov 5th doing my own for the whole street.
Running about in the dark never seeing what is going on above.

Making your own lets you stop and admire it as an individual entity.

As for your choke comments I do believe that judging the fairly alarming whoosh that such a small fountain gave out along with the 15ft spray I was near making a daisy cutter.

I suspect that for that type of mix it was more suited as a rocket choke.

I really am feeling my way here and no comments, however obvious to your seasoned selves will be regarded as condescending.

I really should have started unchoked I suspect.

I am suspending experimentation until my visco arrives anyway.

All coments gratefully received.



Barring "you're nicked!"

Edited by JackFlash, 11 May 2009 - 08:57 AM.

[Potassium chlorate]

60% potassium nitrate
25% coarse charcoal
15% sulphur

Just mix it with a spoon for a couple of minutes, then fill it in a 3/4" tube. Press it with a dowel and ram a clay nozzle. It could be anything from 4" to 15" long. Simple, easy-to-get chemicals and the risk of accidental ignition is extremely low.

[MDH]

It seems like the higher dross in this would somewhat smother the amount of sparks produced. Is there anything in particular you usually mix this with? (I am thinking equal parts of spherical aluminum and sodium bicarbonate to react directly with the hot sulfur).

[Potassium chlorate]

I'm actually pretty new to fountains, so I have just made a couple of them with this composition. Though aluminium would be my chemical of choice if I added something to it.

[Joeeee]

I'm actually pretty new to fountains, so I have just made a couple of them with this composition. Though aluminium would be my chemical of choice if I added something to it.

anyone knowss a formula/composition for a twinkler gerb?

[pyrotrev]

anyone knowss a formula/composition for a twinkler gerb?

Do you mean a glitter gerb?

[MDH]

35 BP
20 KNO3
7 BaNO3
10 Sulfur
8 Charcoal
10 Aluminum
8 Delay-Agent
2 Iron Oxide

That's probably a bit overfueled. I used to use it in 1" ID, 4" tall fountains with a very wide choke.

Barium nitrate is really needed for the effect to work.

Just start with a mixture of:

25 BP
35 KNO3
16 Sulfur
14 Charcoal
10 Aluminum

Then start substituting or adding small amounts of other ingredients, such as barium nitrate, sodium chloride, barium carbonate, sodium or calcium carbonate, antimony or iron sulfide, and a flash enhancer like iron oxide and calcium sulfate.

[Joeeee]

35 BP
20 KNO3
7 BaNO3
10 Sulfur
8 Charcoal
10 Aluminum
8 Delay-Agent
2 Iron Oxide

That's probably a bit overfueled. I used to use it in 1" ID, 4" tall fountains with a very wide choke.

Barium nitrate is really needed for the effect to work.

Just start with a mixture of:

25 BP
35 KNO3
16 Sulfur
14 Charcoal
10 Aluminum

Then start substituting or adding small amounts of other ingredients, such as barium nitrate, sodium chloride, barium carbonate, sodium or calcium carbonate, antimony or iron sulfide, and a flash enhancer like iron oxide and calcium sulfate.

is this for a twinkler gerb?

[MDH]

It will definitely twinkle.

[Joeeee]

is this for a twinkler gerb?

What type of aluminium ??

[Creepin_pyro]

-200 mesh, spherical might be a good starting point. There's probably a range of Al which would work reasonably well. Lloyd has a few good glitter gerb formulas which will be archived here and on rec.pyro.

[Joeeee]

-200 mesh, spherical might be a good starting point. There's probably a range of Al which would work reasonably well. Lloyd has a few good glitter gerb formulas which will be archived here and on rec.pyro.

but what type of aluminium? atomized?