11 replies to this topic

[pyrotechnist]

Has anyone had any success in these? I have tried and tried using both Takeo Shimizu and other more tuned formulas and failed in each one . The method I used was to grind both the KNO3 and pine charcoal together very well and then add the sulfur and thoroughly mix. Then put a few milligrams of the composition within tissue paper and twist it up. The formula I tried recently was:


Potassium Nitrate 60
Sulfur 24
Charcoal 16

I made a 1 gram batch of this and no round molten blob formed and if one does it just ends up getting to big and falling off or working a little and then fading away . If anyone has had success in these could you please give your formula and the grams of each component that worked best?

[bigtonyicu]

I love making these easy fast and fun, but my sulfur level is higher, I use:

KNO3 60%
C 12%
S 28%

But more then likely it's your technique that's giving you problems, are you getting a slow ish black powder that burns with less smoke?

If so, try the above mix and use the following technique,

Ball mill your sulfur and potassium nitrate but NOT the charcoal for 4-6 hours (more then likely your charcoal is too fine by the time it get lit it's burned out); then screen in your charcoal. I pass mine through a meat grinder and then mortar and pestle, I looks very much like air float but in actuality it's coarser and gives much better longer lasting sparks.

Let me know how it goes,

Edited by bigtonyicu, 30 July 2008 - 06:20 PM.

[pyrotechnist]

Thank you , mine normally burns to quick, so much so the blob (if it forms) drops off. When the comp is put into tissue paper is it spread out or kept in a blob all together within the tissue wrap?

[bigtonyicu]

the blob is really held to gether by the surface tension of the molten sulfur the paper is there only to keep everything together prior to igniting.

if the sulfur content is too low, no enough blob forms to hold the rest of the composition together

[pyrotechnist]

The only problem for me when weighing the pine charcoal is the darn stuff is that fine it will not register until you dump loads on my scales which are 0.1 g accuracy. So I never know if I have enough, to much or to little of charcoal. How many grams of your formula have you gotten to work best?

[portfire]

I'm not sure if it will help, but I have a study on Senko Hanabi from 1927. It does mention using very fine Carbon, if you want me to send it PM me

Dean

[phildunford]

I'm currently working on 'Old English Flowerpots' which produce the similar 'spur fire' effect. The formula for these use lampblack.

In the translations from the Japanese, you often see mention of pine soot - so does this mean pine charcoal, or something more like lampblack, which you could describe as 'soot'?

[bigtonyicu]

How many grams of your formula have you gotten to work best?

By changing your charcoal to something coarser it makes life much easier, but I tend to make 100g of it at a time.

I was thinking after I posted yesterday, one thing to be careful when making them is how much composition you actually put in them, the trace left on the paper should be very fine. if too much in place on it, the combustion temperature will increase and burn more quickly and might cause the blob to get pushed off by the gasses or simply to fall to the ground under it's own weight.

In the translations from the Japanese, you often see mention of pine soot - so does this mean pine charcoal, or something more like lampblack, which you could describe as 'soot'?

Soot is definitely is lampblack, the main advantage comes from the fact that the ignition temperature for soot is much higher, and instead of burning vigorously it tends to prefer incandescing (making what appears as sparks) in low oxygen environments. But for making senko hanabi it is no "required" charcoal works very well, it just takes some trial and error

[Creepin_pyro]

It dawned on me the other day that I'd never tried making these.

Here's a timelapse video of my 4th attempt...

I ended up adding a pinch of bicarb to slow the burn somewhat, seemed to do the job. I ended up using small silver rizla papers to roll them which seemed to work rather well...

http://www.flickr.co...mus/4307204815/

I will upload the photos soon...

Now I need to get some decent branching charcoal - this was willow.

[pyrotechnist]

Very good first attempt, I have yet to perfect the formula to get the same result each time I can only achieve a good result now and again.

[MDH]

I have produced a similar effect with a mixture of potassium nitrate, sulfur and potassium tartrate. It burns much too fast for that effect though, which is quite nice.

Congratulations on getting senko hanabi to work, though. Do you think we can accomplish colors with the mixture such as red or yellow?

[Tinderbox]

http://senkohanabi.d...ngredmater.html