Fog machine

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A heavy duty smoke machine feeding smoke into a blower to generate fog effects for open air location filming.

A fog machine (also called a smoke machine) is a device which emits a dense vapor that appears similar to fog or smoke. This generated "smoke" is perfectly safe to breathe, although individuals with breathing complications such as asthma may experience some irritation. Most fog machines create the fog by vaporizing a water and glycol-based or glycerine-based fluid. The fluid (fog juice) is injected into a heated block, and evaporates quickly. The resulting pressure forces the vapor out of the exit. Upon coming into contact with cool outside air the vapor forms a fog.

A special effects engineer positions the inflatable plastic tube feeding the smoke to points around the location.

Fog machines are used to create spooky effects in plays such as Dracula, A Christmas Carol, and Macbeth. Fog machines are also frequently used in Halloween displays such as haunted houses or forests. Because of recent (2003-2005) price changes and availability, fog machines can be seen on the doorsteps of everyday houses during the season of halloween.

Fog machines are also useful for industrial purposes, such as visualising the flow of air or testing filters in air conditioning. Fire fighters also use fog machines in their training.

Because of the reflective and refractive qualities of the smoke created by fog machines, they are often used in nightclubs to enhance the effects of lighting and laser arrangements (see also light beam).

Visual Effect produced using a fog machine, conventional lighting, and an ion laser.

Haze machines, or haze generators, are taking over the job of fog generators for highlighting lighting or laser effects. Haze machines are often seen with bands and bigger venues when a lighting effect may need to be visible in the air.

Maintenance Fog/Smoke/Haze machines that operate on a fluid (rather than dry ice) must be cleaned periodically to prevent buildup within the thin tubing. This is best accomplished by draining any remaining fog juice, replacing it with a solution of 20% white vinegar and 80% distilled water, then operating the machine until it emits nearly invisible steam.