Cold Fireworks: What Happens Inside The Machine That Makes Them
Cold Fireworks: What Happens Inside The Machine That Makes Them
Cold fireworks are a spark effect produced by an electric machine that heats small metal granules until they glow, then blows them out of a nozzle as a fountain. There's no combustion chamber, no ignition source, no propellant, and nothing pressurised. Each particle carries only the heat the machine put into it, which is why the sparks stop giving off light in mid-air.
This page is the mechanism reference for the rest of our cold spark library. For the category end to end, including purchase, permitting, and operation, start with how cold spark machines work and come back here for the internals.
What cold fireworks actually are
The visible spark is a piece of hot solid metal radiating light. That's incandescence, the same physics that made a filament bulb glow, happening in a grain of alloy about the size of a coarse sand particle. A conventional pyrotechnic effect burns a chemical mixture carrying its own oxygen supply, which is why the two get different fire responses on a deck. Our cold spark machines vs pyrotechnics page takes that comparison apart.
Open a cold spark machine and the absences are as informative as the parts. There's no combustion chamber, no igniter, no fuse, no electric match, no propellant charge, and no pressure vessel. What's inside is a storage bin, two screws, an electric heater, a fan, and a couple of circuit boards.
None of that makes these machines unregulated. Every fire authority that has published guidance on them, North Carolina and Massachusetts and Syracuse among them, classifies them as pyrotechnics for permitting purposes, because the output is hot metal in an occupied room. Assume a permit applies, and read our fire permit information page.
Inside the machine, part by part
[EMBED YOUTUBE youtu.be/emL_Okl-P0s "How a cold spark machine works" WITH VIDEOOBJECT SCHEMA]
The vocabulary needs sorting first. Operators call the screws augers or corkscrews and the outlet the nozzle. The factories write it differently: Showven Technologies' granted US patent 10,648,782 B2 calls the top bin a loading hopper, the screw inside the heater a rotary conveying roll, the heater a heating loop, and the outlet a spurting port. Both describe the same 5 assemblies, which matters when you're holding a factory parts list and a tech's fault description at once.
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The hopper and the feed auger
Granules load into a hopper on top of the machine. Under it sits the first auger, the one operators call the corkscrew, driven by its own motor. Turning it converts rotation into axial push and moves granules down a metal funnel toward the chamber.
The funnel narrows into a small opening in the side of the chamber, and that opening is deliberately small because it meters. Feeding a controlled trickle into a hot tube is what lets the machine produce a steady fountain for 20 seconds instead of dumping a slug of cold metal into the heat and choking on it.
Feed motor speed is the density control: slower gives a thinner column, faster fills the fountain in. That's the parameter behind the intensity setting on machines that expose one.
The heated chamber
The chamber is a cylindrical tube wrapped on the outside with a heating element, insulated with a sleeve and gaskets so the heat stays in the tube rather than cooking the rest of the machine. A second auger runs down the centre of that tube.
Heating runs the whole length of the tube rather than sitting in one hot spot, and this is the part most explanations get wrong. Granules aren't heated in a batch and released. They're heated continuously while they travel, so temperature climbs along the way and the material arrives at the outlet at working temperature. Showven's patent puts it plainly: the powder "is continuously heated by the heating mechanism attached to the conveying device during the conveying process."
Dwell time is the variable that decides how bright a particle gets. The second auger's rotational speed sets how long each grain spends inside the tube, which sets how much energy it absorbs before it leaves. Slow the screw and the same granule leaves hotter.
Chamber temperature sits in the 480 to 650°C band across the category. Our cold spark safety guide covers what that means for clearances and for the word "cold" in the product name.
The blower and the nozzle
A blower sits underneath and pushes air through the outlet, and it's doing two jobs. It throws the granules clear of the machine, and it supplies the oxygen that lets them burn at full brightness once they're out. The granules carry no oxidiser of their own, so the air is the other half of the reaction.
That makes blower speed the height control: the discrete height steps on a DMX channel are fan speed steps underneath.
Direction is a mechanical choice rather than a software one. An upward machine, a downward fall unit, and a horizontal side-spark unit differ in how the outlet tube is shaped and aimed, which is why you buy a horizontal machine rather than tipping a vertical one on its side. Better outlet tubes also carry an anti-adhesion coating, Teflon or similar, because glowing metal against bare steel builds nodules and eventually a restriction.
The boards and the RFID reader
1 or 2 circuit boards run everything: mains input, the heater and its temperature sensor, the feed motor, the conveying motor, the blower, and the DMX input. On most machines that's 2 DMX channels, one for height and firing and one for utilities like pre-heat, emergency stop, and clear-out. Our cold spark machine DMX control page carries both channel maps.
Many machines also carry an RFID reader that has to see an authenticated card before the machine will fire. Showven's implementation is metered rather than a one-time authorisation: a 200g card adds roughly 20 minutes of machine working time, capped at a 30-minute recharge per session. Some iSparkFX models need a card and some don't, the M1 NO RFID and the CSF-01 being the card-free options.
Boards are the part most often killed by something outside the machine, and shared circuits are the usual culprit. Our cold spark machine power requirements page has the arithmetic behind the dedicated-circuit rule.
[EMBED YOUTUBE youtu.be/8M6fozAvDqI "Cold spark machine teardown" WITH VIDEOOBJECT SCHEMA]
Why the sparks go out in mid-air
A granule leaves the nozzle carrying a fixed amount of energy and no way to make more. From the instant it's airborne it's spending down what the chamber gave it.
Zirconium and titanium are the alloy of choice partly because they hold that energy well. Both have low thermal conductivity for metals, so heat doesn't race out of a small particle the moment it's exposed to air. The grain stays hot enough to emit visible light through the length of its arc, then falls dark.
Particle size is the other half of it. A grain has a lot of surface area for its mass, so losses win quickly. Larger grain carries more energy, glows longer, and travels further, which is why outdoor granule grades are coarser and need more standoff.
You'll see marketing for this category claiming the sparks themselves are close to room temperature. Set that aside, because a solid at room temperature emits no visible light at all and these particles are visibly incandescent. The true version is narrower and more useful: a particle this small, radiating this fast, transfers very little total heat to whatever it lands on. That's what makes the effect usable in front of an audience. It's still hot metal, which is why the clearance and extinguisher rules exist.
Why the colour range is fixed
Colour comes from black-body radiation, so it's set by the temperature of the hot solid rather than by any chemistry you can choose. Hotter particles read white-silver, cooler ones gold and then red-orange as they fade. That gradient is the entire palette, with no blue, no green, and no electronic colour control on any machine in the category. Anything advertising coloured sparks is either an LED fixture or a conventional pyrotechnic device using metal salts.
Branching, forking sparks are a separate phenomenon: carbon burning inside hot iron bursts the particle apart, which is what a steel-wire sparkler does. Titanium and zirconium give brilliant white streaks that hold their line. Where a client wants brand colours, the lever is room lighting, since brighter light washes the effect out and a darker room dramatises it. Composition and grade detail sits on our cold spark granules page.
Warm-up, run time, and the 30-second cycle
Warm-up runs roughly 3 to 8 minutes depending on model, supply voltage, and room temperature. Showven units land near 5 minutes. The wait is thermal rather than electrical: the element has to bring a mass of metal tube up to temperature and hold it there. A chamber only partly up to heat still fires, producing short dull output that reads like a granule problem, which is why techs chase the wrong fault.
Most machines cap a single activation at 30 seconds and then shut the effect down as thermal protection for the chamber and motors. The operator re-triggers, usually with a slight dip in height while the chamber recovers. A cue written for 45 continuous seconds is a cue the machine won't deliver.
Run time comes off the granule pack rather than the clock. A 200g pack gives 12 to 15 minutes of cumulative effect on a standard machine, and a 50g pack gives 3 to 4 minutes on a mini. High-output units burn around 70 g/min, so a 30 ft machine empties a pack far faster than a floor unit.
What the mechanism tells you about how these machines fail
Every common fault maps to a specific point in the feed path, and knowing the path shortens diagnosis considerably.
Weak or absent output usually sits in the hopper or the first auger: an empty bin, damp granules that have compacted and bridged instead of flowing, or auger damage. Output that flickers mid-activation is normally a partial blockage or a worn screw. Low height with clean flow points at blower or motor wear or the wrong granule grade. Visible unburnt grain hitting the floor means the chamber is overloaded or fed material it wasn't tuned for.
The clear-out function exists for the same reason. It's a dedicated DMX function running the chamber auger and the blower with no new granules entering, sweeping the hot tube empty before the machine cools with material inside it. Our cold spark machine maintenance page covers the routine and the teardown interval.
95 to 98% of the faults reported to us turn out to be operator error rather than a broken machine: wrong power, a bad DMX or power cable, a controller fault, RF interference, the wrong granule type, debris in the granules, or a machine never cleared after the last show. You only learn that ratio by doing the repairs, which is why we stock heating elements, hoppers, blowers, blower motors, DMX boards, and electronics boards for the machines we sell, mostly shipping same day. Current stock by output class sits on our cold spark machines for sale listing.
[INSERT LABELLED CUTAWAY INFOGRAPHIC: GRANULE PATH FROM HOPPER TO NOZZLE WITH CHAMBER TEMPERATURE BAND MARKED]
Frequently asked questions
What are cold fireworks?
Cold fireworks are a spark effect produced by an electric machine that heats small metal granules until they glow, then blows them out of a nozzle as a fountain. There's no combustion chamber, no ignition source, no propellant, and nothing pressurised. The word "cold" describes how the particles behave once they're airborne rather than the machine, which runs its chamber between 500 and 620°C.
How do cold fireworks work?
Granules load into a hopper on top. An auger, which operators call a corkscrew, drives them through a metal funnel into a small opening in a cylindrical chamber wrapped in a heating element. A second auger runs down the centre of that chamber and moves the granules along until they're glowing. A blower sitting underneath throws them out of the nozzle. Warm-up takes 3 to 8 minutes.
Are cold fireworks real fireworks?
They contain no pyrotechnic composition and burn nothing. Every fire authority that has published guidance on them, North Carolina and Massachusetts and Syracuse among them, classifies them as pyrotechnics for permitting purposes anyway, because the output is hot metal. Treat "real fireworks" as a regulatory question rather than a chemical one, and assume a permit applies. Our fire permit page covers the filing.
Do cold fireworks contain gunpowder?
No. The consumable is a zirconium-titanium alloy granule, some formulations including magnesium, with no oxidiser and no gunpowder anywhere in the machine or the pack. Because there's no oxidiser, the particles depend entirely on ambient air, which is part of why they stop glowing so quickly after leaving the nozzle. A conventional gerb carries its own oxygen supply and behaves nothing like this.
Why do cold spark particles burn out in mid-air?
Each particle is a small piece of metal carrying only the heat the chamber put into it. Zirconium and titanium have low thermal conductivity, so a small particle holds that heat long enough to glow through its arc. Once it radiates that energy into the surrounding air it stops emitting visible light and falls as cooled grain.
What is inside a cold fireworks machine?
A hopper, a feed auger, a metal funnel, a cylindrical heating chamber with an element around the outside and a second auger down the centre, a blower underneath, a nozzle, and 1 or 2 circuit boards handling power, heater, motor, and DMX. Many machines also carry an RFID reader that has to see an authenticated card before the machine will fire.
Are cold fireworks the same as cold spark machines?
Same device, different word. "Cold fireworks" is the consumer-facing search term. "Cold spark machine" is what the industry writes on an invoice. "Cold pyro" is what a production rider says. The hardware behind all of them is identical. Our terminology page maps every name in the category and explains which one to use with a venue or a fire marshal.
Do cold fireworks make noise?
The effect itself is close to silent. What you hear is the blower and the motors, a steady fan-like hum while the machine runs. There's no report, no crack, and no concussion. That's one reason these get used indoors, near speaking talent, and in rooms where a conventional pyrotechnic effect would be unusable.
Cold Fireworks | CryoFX®
Updated - 08/06/2026.