Two basic but fun fireworks can be made simply using visco
style fuse.
This is because visco style fuse, using a fast burning black
powder, generates thrust as it burns and in small amounts can therefore propel
itself.
Cut into small sections, visco style fuse can make “flying
fish”. Flying fish produce an effect similar to a tiny rocket but they are not stabilised
by fins or rotary motion. The result is a sparking, glowing dart which flies off
in any direction it wishes (as seen below) and can be used in mines, shells and rockets.
Fuse spinners also take advantage of the thrust generated by
visco style fuse. Simply bend the fuse into a curve, or producing the visco in
this manner, will form a spinner. This is similar to the flying fish effect but
the direction of the thrust is projected at an angle to the rest of the fuse
body. This spins the fuse and prevents it flying off in any given direction.
This produces a simple spinning effect showering sparks in all directions and
can be used in the air and as a ground effect, as shown in the video below. The
video also shows a simple flash powder report added to one of the spinners for
an extra effect.
In short, fuse paper is made by
impregnating paper (typically kitchen towel) with a potassium
nitrate solution which is left to dry. Blackmatch is produced by
treating threads (or string) with a slurry of black powder to form a coating before being left to
dry.
Lots of people make fuse paper and blackmatch as it's seen as being easier than making your own visco.
This is true of the initial outlay of time and resources, but once you've made a visco weaving model it's actually faster and a lot less hassle to make visco than fuse paper or blackmatch.
An important point is that although fuse paper and blackmatch can prove adequate, it's much less reliable than visco style fuse - as demonstrated in the video below (description underneath).
The first clips show that fuse paper can easily be blown out and whilst blackmatch is unlikely to go out its burn rate rapidly increase with increased airflow, neither of which is good for safe timings of fireworks. Visco fuse doesn't have this issue.
Fuse paper and black match are both unreliable in confined spaces as shown in the rocket nozzle example, occasionally burning out just as the fuse reaches the exhaust port. Again, visco fuse doesn't have this problem.
Finally, the lighting and burn rates of fuse paper and blackmatch can be inconsistent. Fuse papers burn rate will often slow and speed up again whilst blackmatch tends to burn a little too fast for ideal use in firework timings. In any event neither of these are suitable for more complex devices as they'll not withstand the force of a lift charge/break charge. The final clip shows blackmatch burning too fast, whilst fuse paper doesn't light at all in this example. Visco style fuse ignites perfectly and burns with a slow and steady rate.
Visco style fuse is also waterproof.
These are just a few reasons why visco style fuse is preferable to more basic fuses.
With Christmas and New Year's coming up we’re reducing the price of our visco fuse machine plans (either version) by 20% until midnight on the 31st of December (GMT).
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Simply use discount code “Festive20” at the checkout! Merry Christmas!
Nitrocellulose lacquer is a flammable binding agent used to coat commercial Visco style fuse. The lacquer’s principal functions are to hold the fuse together, make it durable to manipulation and also to make it waterproof.
To make the lacquer you will need Acetone (a cleaning solvent available at most chemists), a glass jar with an airtight lid, scissors and ping pong balls.
Take a ping pong ball (this contains the nitrocellulose) and cut it into small pieces. Cutting the ball into small pieces increase the material’s surface area and speeds up the process of turning this solid into a liquid.
Place these pieces into a glass jar with a sealable airtight lid.
Pour Acetone into the jar so that it a little more than covers all of the pieces of plastic.
Tightly secure the lid and allow the Acetone to fully dissolve the plastic. The result should have a consistency similar to PVA glue or a medium paint. The time that this process will require depends on how much lacquer you are attempting to make. Personally, as I don’t tend to make much fuse at any one time I use a small jam jar, one ping pong ball and about 30ml of Acetone. This produces enough lacquer to coat about 2 feet of fuse and takes in the region of 3 hours to fully dissolve into a smooth lacquer with a consistent viscosity. You can accelerate this process by occasionally shaking or stirring the mixture.
I then apply a small amount of lacquer to the end of my fuse which is still under tension in my Visco machine. Once dry, this allows me to cut the fuse at this point without the thread unravelling.
I then feed this fuse tip through a small opening in a “coating tank” – a rather grand name, for in my case this constitutes a photo film canister. The fuse tip is passed through a slightly larger opening in the other side.
The nitrocellulose lacquer is then poured into the tank and the fuse is drawn though it directly from the visco machine. This gives the first coat and binds the fuse together. The fuse is removed from the machine and a further coat or two is applied as necessary to ensure an even and unbroken coverage. The result is a durable fuse capable of withstanding manipulation; lift chargers, break charges and burning in wet conditions, or even underwater.
A video showing these steps as well as a burn test of the nitrocellulose lacquer alone can be seen in the video below:
Even for the amateur pyrotechnic enthusiast, there will
quickly come a realisation that a safe and reliable fuse is not only an
essential piece of kit for successfully setting off fireworks predictably, but
that they are the most underappreciated part of any firework.
Not only does a safe fuse greatly reduce the risk of injury
and damage but it’s crucial for the timing of both simple and complex
pyrotechnic firing arrangements. Even in the most complex electrical firing
systems used by professional pyrotechnicians, after the ignition of a firework
begins all subsequent timings within that firework will be dependent upon a
chemical fuse of some kind burning at a set rate.
There are many types of fuse with different properties
designed to fulfil different requirements. Arguably the most important of these
(at least in the beginning) to the budding enthusiast is the fuse used to initially
light a pyrotechnic device. This type of fuse is often referred to as “safety
fuse”, “cannon fuse” or most commonly of all “visco fuse”. There are many
places where restrictions on the sale of fuse prevents (or makes it difficult
for) a pyrotechnic enthusiast to obtain fuse. Even where you can purchase fuse
you might be looking to pay a relatively high price for a short length of fuse.
Whether a commercial fuse is available to you or not, there are many good
reasons for making your own fuse, such as:
After
the initial cost of materials, production of homemade fuse is often much
cheaper than buying fuse.
You
can tailor the fuse to the specific requirements you have for a given
application i.e. burn rate, fuse dimensions etc.
You
can have fuse “on tap” whenever you want it.
Having
the satisfaction of making the fuse yourself – after all, the whole reason
you’re making fireworks in the first place instead of buying them (fuse
and all) is because you appreciate having put in the effort to understand
the processes and get it right for yourself.
Therefore, many amateur enthusiasts look towards producing
their own fuse – with a greatly varying degree of success depending on the type
of fuse they’re trying to replicate. The most desired option is to try and make
a visco style fuse. This is because a visco style fuse offers the greatest
benefits to the user. Other fuses like black match and fuse paper can produce
the desired results in some cases, but these are not waterproof, may have an
inconsistent burn rate and can fail to continue burning in a confined
environment. Visco style fuse has none of these problems.
Unlike some homemade fuses, in order to make a consistent
product of the visco type there needs to be a standardisation of the production
process and this can only be done using some form of mechanically driven
machine.
The designs of machines which produce visco style fuse can
vary greatly depending on the needs and constraints of the user. Although there
is a lot of information on the internet with all manner of details regarding
the construction and design of visco machines, these tend to be incomplete.
For the average enthusiast the production of fuse will be a
relatively low level affair requiring only a few feet per time as opposed to an
industrial scale operation. There are many devices which others have made which
work beautifully, but unless you’ve got access to a workshop and a fair amount
of technical knowledge these devices might be beyond the fabrication skills of
most beginners and tend to put people off.
My specific needs as an amateur enthusiast for a visco
machine was a device that was:
Compact,
and so easily stored.
Easy
to construct.
Cheap
to build.
Easy
to operate.
Quiet.
Could
produce small to medium lengths of fuse easily and quickly.
Hand
powered – reducing complexity, cost (both of materials and in operation)
and noise.
This in turn would need to produce a fuse that:
Had
a consistent burn rate.
Was
reliable – i.e. it would continue to burn in confined spaces, such as the
exhaust port of a rocket nozzle.
Could
be waterproofed.
Would
be strong enough to withstand pyrotechnic charges (such as those in lift
charges and break charges) but still be flexible enough to cope with a
certain amount of manipulation.
The eBook available here details the
construction and use of the machine that I eventually made. It fulfils all of
the above requirements for both the machine and fuse produced. The finished machine
looks simple, and to be fair, that’s the point. It took a long time to make a
model which would meet the criteria listed above yet be as simple as possible
and use readily available materials. The less complicated a system the less
there is to go wrong with it, and anyone who has battled the trial and error of
getting a visco machine to work will testify that the fewer times you have to
thread the “dies” the better!
The model produces fuse at the rate of 3 feet per minute and
the fuse itself has a diameter of 2mm with a consistent burn rate of 0.7cm/sec,
even underwater, and can be seen in action in the video below.
