The division of fire dust particles

A single particle of the fire dust is a mixture of liquid and solid substances and has cohesion. When a strong wind blows against the particle, it is divided into many smaller particles by the occurrence of a spray-like phenomenon. This is called fire division . 

Fine fire division produces quite beautiful fire dust, but its life is shortened. On the contrary, rough fire division decreases the beauty, but lengthen the life. In view of this, it is necessary to plan the composition or the manufacturing process of the composition to obtain proper fire division according to the intention. 

The fire division occurs most easily when the cohesion of the particle is weakest. With the fire dust of black powder-type compositions the point may be a content of about 7% sulphur. If the sulphur content is larger than that, the potassium sulfide, K2SX. content,in a particle increases to produce strong cohesion, which makes the fire division more difficult. If the content is less than that, unburned charcoal aggregates and in this case the fire division is also difficult. 

The manufacturing process of black powder type composition has a large influence on this division. The three components, potassium nitrate, charcoal and sulphur, must be intimately mixed if we hope to get good effect. For example for a composition of 58% potassium nitrate, 7% sulphur and 35% charcoal, the average life time of the fire dust from this 

Moreover the fire division depends upon the wind velocity, i.e. for a flying star it depends on the velocity of the star. The most representative example is the Chrysanthemum of Mystery (see 15.2). When we ignite this star on the ground no fire division occurs, but when we fire it through the air we see a lonely kind of fire dust which is caused by the movement of the star. Another good example is the star silver wave (see also 15.2).  

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The colour of fire dust 10.3 The division of fire dust particles... 

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