HPAVC/HPAVC CD-ROM.iso/pc/VORTEX.ZIP/065.TXT

Text File | 1996-07-20 | 3.7 KB | 76 lines

                             Pyrotools


Making fireworks is not only a challenge for your knowledge and skills
in chemistry. You also have to be able to make some tooling yourself,
if you do not want to spend a fortune buying from others. If you have
a friend with a lathe and a drill press, you are one lucky pyro! But
you still have to be able to tell him what to make. As I am still a
student, I do not have the money or the space to invest into
machinery. But I have a friend who has got it all! And as he turned
out to be a rocket freak, what was then more natural than asking him
to make me a rocket spindle?
The need for highly specialized tooling for each size of rockets,
makes life hard. I wanted to be able to use one rocket spindle to make
different types of rockets. What I did, was to settle on one rocket
diameter. Then the length of the spindle could be adjusted by stacking
plates around the spindle, in order to achieve a spindle length
suitable for the

Stinger missile. You can see the tube compared to the
spindle. This rocket (20 mm ID) can launch 130 grams payloads. <p>


Another beautiful effect that demands specialized tooling, is the
crossette. It is a cylindrical, pressed star, typically a
charcoal/glitter composition. The special shape of the plunger creates
a hole in the crossette that is filled with a bursting charge. The
smallest tip creates a fire transfer hole, so that when the crossette
is ignited in one end, it will burn until the flame reaches the small
hole that leads the flame to the burst. If everything is properly
made, the crossette should split into several (four or more)
pieces. The crossettes can be fired one by one from small mortars, or
they can be put into a shell to get a crossette shell. <p>


In order to press crossettes or the more sensitive whistle rockets,
some type of press has to be used. As I do not always carry my 40 kg
press around where ever I go, I had to make a quick and cheap press
when I went home one day. I constructed a nutcracker type of press
from two pieces of 5 X 10 cm (2" by 4") wood,
about 2 meters long, and two shorter pieces . I also used a piece of
thick wood plate as a
shield, just in case the rockets should explode when pressed. The
whole press was made in about one hour, and it is powerful enough for
most applications. The maximum pressure is about 500 kg. If higher
pressure is needed, metal should be used when building the press, or
one could use an hydraulic press.<p>


Here is another picture showing the press "in action". As you can see,
the important part is that the arms of the press is almost parallel,
or else the force from the press will not be directed straight down as
you want it to. You might need to build some sort of mould to keep the
rammers or the plunger from bending sideways.<p>


What I did was to make a wooden support, that keep the rammer and the
casing of the rocket on line. You can see the pieces of wood with a
hole that is about one mm wider than the casing. Two of the tree parts
holds the casing in position, while the last and upper piece keeps the
rammer from bending. The tree pieces are easy to put together, and the
mould works perfect in order to prevent bending of the casing. <p>

When all the pieces are put together, only the rammers can be
seen. The moulds are made to fit a 20 mm and a 10 mm ID rocket, having
2-3 mm thick walls. I have to use them until I can make a press with a
piston that moves vertically. Even then, some support for the smaller
rockets might be needed. <p>

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