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HOW
DO THEY MAKE THE BEAUTIFUL COLORS OF STARS?
 The
explosive charge at the center of the shell is
made of black powder or flash powder (composed
of potassium perchlorate, aluminum powder,
and/or magnesium which, upon ignition, creates
a violent explosion combined with a flash).
The explosion sends the burning stars out in a
particular pattern determined by the way the
shell was packed by the shell maker - creating
the colorful effect the crowd sees.
How to
make various color of fireworks?
 Do
you recall an experiment called "flame
reaction" from your chemistry class? It
is that burned chemical compound including
specific element, flaming up with particular
color of each element. A color of fireworks
applies to this "flame reaction".
The stars of fireworks can be created by
mixing three main powders. It is a
combustible material which promotes the
oxidant and combustion by which the mixture
and oxygen with which the color is put out are
created.
HOW
THE COLORS OCCUR
The
colors of fireworks come from bright-burning
metallic salts. In fireworks there are six
common colors, made by adding a specific
chemical compound.
 White
= is produced by magnesium or aluminum
or titanium
Yellow = by sodium salts
Red = by strontium nitrate
Green = by barium nitrate or chlorate
Blue = by copper compounds
Orange/Amber = by charcoal or other carbon or
iron compounds
Deep blue and purple are the most difficult
colors to create because they have a very
narrow band on the color spectrum, requiring
the chemical reaction to be absolutely
perfect. In fact, the creation of a deep blue
flame remains one of the great challenges to
pyrotechnicians. However, blue and green are
considered the most dangerous colors to
produce.
 DEEP
YELLOW.......................................................................Sodium
Salts
YELLOW........................................................................Calcium
Carbonate
BLUE.....................................................................................Copper
Oxide
SILVER.......................................................................................Aluminum
RED................................................................Calcium/Strontium
Carbonate
CRIMSON.....................................................................................Strontium
GREEN.................................................................................Barium
Nitrate
GREEN
AND BLUE.
........................................................................Copper
ELECTRIC-WHITE................................................Magnesium
and Aluminum
Chlorine
compounds are used to intensify or brighten
colors. Recent stars show a tendency to be
more brighter than usual by using magnesium's
etc. This has been achieved by mixing
magnesium's, slight neutral tints like
difficult pink and purple. Trail used for
chrysanthemum-star puts out a little dark
orange when charcoal burns by chiefly using
black gunpowder. Compound
is made of various kinds of powders and
chemicals. Though more safe chemicals are
used, this is the most careful and dangerous
process to date. Pyrotechnicians use empty
hands to mix the compounds so they can feel
the condition of chemicals.
THE
FORMULAS
There are only about 100 top fireworks
manufacturers in the world. Each company's
formulas are closely-guarded secrets. The
chemical and powder recipes are often handed
down through generations of families. The
color, animation, sound and flight
pattern of each shell depends on its design
and on the blend of its chemical ingredients.
Changing
color of stars after explosion is an original
technology of the Japanese fireworks. This
change is 
based on the structure of changing color star.
Concentric sphere consists of some layers of
powder which burn another color each
other. This type of star, called "multi
coated star" is made of materials like a
seed or ceramics grain in the center, and
coated over with powder. This coating work is
performed by "Star-rolling machine."
while spreading and drying them over drying
table under the sun after one powder layer
grows more thick. It is then dried and coated
with powder again. Each star is grown bit by
bit up to final size. It takes about 17 days
to finish twenty millimeters across petal
stars used in twelve inch round shell .
MAKING
STARS
Homogeneous completion is needed for size and
quality of each produced stars for color
change, and for bursting all at once. There
are some methods of making
stars. Multi coated star take great deal
of time. A unique Japanese method is applied
in it's creation. Pressed stars are popular in
any foreign-made fireworks. It consists of one
kind of powder, as it's easier than a coated
star and it has the same quality.
S TARS
Each
shell is very carefully constructed in a
fireworks factory. A chemist produces the
powders and presses or rolls them into pellets
called 'stars' which are spherical,
cylindrical or cube-shaped. The diagrams below
show the different types of stars made.
Stars
which are cut into cubes
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Stars
which are "piped"
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Stars
that are "pressed" into
cylinder-shape
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Stars
which are "pumped" into
cylinder-shape
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Stars
that are "rolled" into
sphere
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Star-rolling
machine coating pellets
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When lit, the stars produce a brilliant ball
of fire. They are made with oxygen-rich
components such as strontium nitrate,
potassium perchlorate, potassium nitrate and
potassium chlorate. The star contains both
oxidizer and fuel. When the oxidizer burns
with the fuel made of charcoal, titanium
powder and aluminum powder or other metal or
carbon-based mixtures, the reaction to the
burning of both oxidizer and fuel creates the
effect of color.
The shell maker assembles the stars within the
shell casing, in a careful configuration that
determines the height at which the star will
be expelled and so as to produce any desired
effects (such as the star being
expelled in a particular shape such as a heart
or circle).
(Photos
and articles courtesy of Japan-Fireworks.com) |
