iron's blog

Senko Hanabi

I was at my local hackerspace hackalot last new year’s eve. For me, new year’s eve requires oliebollen, carbid explosions and fireworks. I want to make each of these myself (Ofcourse). The morning of old year’s day is spend making the batter for the oliebollen. The afternoon is spend frying the oliebollen, and making a lot of noise using carbid.

The evening is spend with friends, and lighting fireworks. I have found some videos online explaining how to make a small sparkler called “Senko Hanabi”. The composition of the sparkler is relatively simple, you only need 4 ingredients, all of which are simple to obtain.

  • Charcoal (preferably from a tree which has a lot of sap)
  • Sulfur
  • potassium nitrate
  • Packing paper

A picture of our results can be found below:

The final result

Preparing the gunpowder

The ingredients are identical to the ingredients of gunpowder, however, the ratio between these ingredients that is required for senko hanabi is different. To make a batch of powder that will create a good numer of sparklers (more than 40) prepare the following quantities:

  • 3 gr potassium nitrate
  • 1.2 gr sulfur
  • 0.8 gr charcoal

and grind them together into a mortar and pestle until they are throughly combined as a fine powder.

A mortal and pestle filled with powder

You should be left with a fine, dark gray powder.

Creating Senko hanabi

To create the sparkler, you will need to cut your packing paper down to size, The paper should be a right angle triangle with the sides connected to the right angle being 24cm and 4cm long. A picture below shows the dimensions

Senko hanabi paper

Rolling the powder into the paper is difficult, and hard to explain. My recommendation would be to watch this video. which shows it clearly.

The results

If the powder is folded properly into the paper, you should be able to light it using a normal lighter. The senko hanbi should then burn rapidly for a few seconds, until it starts forming a small droplet at the end which starts to emit sparkles.

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