Warimono shells

Pasting is peculiar to Japanese firework manufacture. Stars are allowed to grow into a spherical shape by sprinkling the powder of a composition on to core grains. This process is popularly applied for the manufacture of colour changing stars used for the Warimono shells Chrysanthemum. In Japan maximum effort is made in the production of stars of this kind. 

The most popular construction of a Warimono shell is shown in Fig,88.-/ For a precise description see Lancaster s book on page 258. 

The loaded shell is pasted with many layers of a strong paper, Kozo or kraft-paper, especially with Warimono shells to allow the bursting... 

Table 23 The standard values of stars for Warimono Shells...

The flowsheets of representative fireworks may be shown as follows (1) Warimono shells... 

Table 23 The standard values of stars for Warimono Shells Table 2. The standard values for the bursting charge of a Poka shell(using black powder)...

In this table "Large" is used for Poka and "Small" for Warimono (Chrysanthemum). Warimono is manufactured by pasting many layers of paper on the sphere and the completed shell has a thicker wall than that of Poka. It is necessary to manufacture both Poka and V/arimono with the same external diameter since they are both used in the same size of mortar. 

There are three requirements for the bursting charge of Warimono to break the shell into pieces, to ignite the stars and to project the stars with an uniform trajectory with the least curvature. Indeed the bursting charge is the motive power of the shell, and it is essential to concentrate our energy on this research just as much as on the stars. 

Compositions for chrysanthemum shells(Warimono) must be selected with special care, but for Poka the selection is not as serious as for Warimono. 

Warimono is a shell which displays a flower like a chrysanthemum in the sky. The stars stretch out to form a round flower. The duration of the flower is generally 2 seconds. 

Poka is a shell which displays willows, comets, parachute, reports, whistles, flags, bills etc. rather than a round flower. Poka has less bursting charge than Warimono, and the weight of the shell is only half as large as that of Warimono for the same size. 

The Warimono and Poka shells described above are the most representative in construction, but there are some other shells which lie between these two and some are quite different from them. 

The small flowers are also called, Flower garden or Thousands of flowers . It involves loading many small shells in one big shell. There are two types Warimono(Fig.ll5.(A)) and Poka((B)). The corresponding... 

This shell resembles Warimono in construction, but the bursting charge is somewhat weakened and the life of the stars is prolonged to about 8/n> 10 seconds. The composition of the stars is the charcoal dust... 

This shell is also a kind of Warimono. Each of the main stars contains a cracker as the core. When the flower has been developed in the sky, the stars crack as the burning ceases and they make a great deal of /... 

The description here particularly refers to the bursting charge of the chrysanthemum shell which are called "Warimono" in Japan. A different bursting charge is used for the other kind of shell called "Poka" which simply uses black powder grains. 

It may well be a Japanese custom to sit on the floor to assemble shells, but it is rational, for it is possible to arrange all the components and tools around the worker and to avoid the shock caused when things fall on the floor. (But as described later, for shells which require less explosive than Warimono a working bench is often used in ordinary manufacture.) The operator must take care not to build up a mass of material around the working area. When chlorate compositions are used, have a wet cloth to hand, and wipe the hands with it immediately after handling each composition. Cutting powder pasted paper or quick match must be done in another room. 

The Poka shell sphere must be broken into two hemispheres along the joint when it explodes, otherwise all the contents will not be thrown out or they will be damaged by fire. This is quite a different requirement from Warimono. The strength of the joint therefore must be a little less than that of the hemispheres. Fig.114 shows an accident which occured, when the joint was stronger than the hemisphere. 

This shell is also a kind of Warimono. Each of the main stars contains a cracker as the core. When the flower has been developed in the sky, the stars crack as the burning ceases and they make a great deal of noise. For the noise composition, red explosive is used because it can produce a loud noise with only a small amount of composition. The explosive in the wet state is rolled with a sheet of Kozo paper into a cord, which is cut in small pieces while it is still wet. The pieces are coated immediately with another safer composition. These are finished by pasting with composition as with ordinary main stars. 

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