Introduction: Make a SFX Fire Projector

Picture of Make a SFX Fire Projector
  • Fire, if used improperly, can be very dangerous.
  • This project is designed to be used as a special effect and not a weapon.
  • Use at your own risk.

I have always loved working with special effects so why not make my own? I have never been given the privilege to work with a flame projector before so this instructables creation is just a prototype for proof of concept.

In pyrotechnics, a flame projector is a special effects device that projects a column of flame upwards for a short, determined, and controllable period, usually on the order of a few seconds. It is popular at concerts, stunt shows, and theme parks. The projector usually enables a type of fuel for the combustion, but powder is also a viable option seen in basic models. Because many people haven't attempted this project before, I decided to experiment with propane. Propane is typically a gas but is commonly stored at a liquid state, which will hopefully provide a better projection. I will be using a high voltage spark to ignite the gas.

Step 1: Materials

Picture of Materials

All the key materials are pictured above.

  • 1" square rods cut to 20" and 2.8" - 3 each
  • An empty soup can which will be used to contain the ignition point. (Mine had a 2.3" diameter)
  • A 16oz portable propane tank (Not pictured)
  • A propane adapter to 1/4" thread
  • A 1/4" electric solenoid - Must be rated for gas. Some seals will
  • deteriorate when in contact with propane.
  • A 1/4" nipple connector
  • Two washers
  • A 1/4" end cap (Due to the lack of materials I did not use this but, a small hole can be drilled in the top to create a higher and faster gas eruption.)
  • A 12v to 5v voltage stepper
  • A 5v to 4000kv voltage stepper
  • A 12v transformer (If the transformer has a fuse, have extra or be very careful not to short any connections)
  • An AC power adapter
  • Two rocker switches
  • A 5v relay (Not pictured)
  • A male/female wire plug connector commonly used in remote control vehicles. (Not pictured)
  • Extra wires
  • Flat L brackets and bolts. (Not pictured)

Since this is a prototype, I will be using hot glue at different stages for testing purposes.

Step 2: The Design

Picture of The Design

I used Autodesk Inventor to create a model of my original design. The can in the center will be supported by three L shaped posts. Each post will be 20" tall and secured 5" from the center creating a 10" diameter. The solenoid and its connectors (gold) will then be bolted to the can while supporting the propane tank (green).

Step 3: The Frame

Picture of The Frame

First, drill a small hole that will snugly fit the 1/4" nipple connecter. Using the flat L brackets, I securely bolted each of the posts together. Once I was happy with the square tubing, I equally spaced them around the can and fastened them with L brackets. I also temporarily glued the contraption to a metal base, so I could test my current design. Once the frame was sturdy, I attached the brass nipple connector through the previously drilled hole with washers and sealed the connection with more glue. This will hold the solenoid. Next, I punched two holes in the side of the can that will be able to hold two wires to create an electrical arc.

Step 4: The Electrical Circuit

Picture of The Electrical Circuit

Above is a very basic drawing of the circuit I used. A safety switch will be used to prevent the propane from accidentally firing while the ignition system is being tested. In my next version, I hope to add dmx capabilities which would be the main method of activation. This model will only have a detachable powered push button that is connected to the relay. The circuit can only be activated when the button is attached and pressed.

Step 5: Testing

Picture of Testing

The project has started to take shape. Everything went almost perfectly. The only problem I was having was with the ignition system. The voltage regulator I had purchased could not generate enough energy to keep the wires continuously arcing. Later on, this becomes an advantage allowing a larger gas cloud to form before it is ignited. I did decide to attach separate wires that could be easily replaced since the plastic coating has a low melting point.

Step 6: The Outer Shell

Picture of The Outer Shell

Next, I decided to make the outer shell. This would hold all of the switches and plugs. I took a 20" X 35" sheet of aluminum and ran it through a sheet roller until it created a complete cylinder with an approximate 10" diameter. I then drilled holes through both the sheet and the rods and bonded them onto another with rivets. Once the final shape was determined, I cut four holes that corresponded to the AC power outlet, both rocker switches, and the wire connector which will be attached to the test button.

Step 7: Wiring

Picture of Wiring

The wiring for this project isn't too complicated. The only part that may be found difficult is the relay. I connected my relay to an external button so that I could ignite my projector from a safe distance. In a later model, I hope to also be able to instal a Digital Multiplex receiver. This receiver would also be able to trigger a different relay. The particular relay I had was designed to be used with an Arduino. It has three pins. One positive, one negative, and another designed to receive data. Im my situation, all i needed to do was integrate it into the positive circuit with a push button switch. The particular button I used was salvaged from an old monitor. When the button is pushed, power will reach the data pin making the electromagnet trigger which will in turn open the entire circuit. In the pictures above, I have updated the circuit diagram to include positive, negative, and data wires.

  • Use electrical tape or heat shrink on all connections to prevent shorting. Also prevent any electrical component from directly coming in contact with the aluminum.
  • When soldering be in a well ventilated room. Fumes are toxic.


Step 8: Final Steps

Picture of Final Steps

Once everything was installed the contraption worked perfectly. I am very happy with the final results. To allow a better oxygen, I drilled more holes in the bottom of the the can. I also decided to not create a top cover on this version. I found that the gas ignites better if the wires are slightly placed above the can instead of inside. The flame now reaches over 6 feet. Im still waiting for a night that isn't too windy so I can show its full potential. Stay tuned for a final showcase video. This is my first instructables tutorial so any feed back is greatly appreciated. Thanks!

Comments

Swansong (author)2017-05-23

Those are fun, they look neat when bands use them in concerts :)

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