Chemical effects can be very dramatic and make a big impact. However, they are not right for every venue. For instance, for Halloween, we have a strict "No Flame" policy. Kids, young or older, pose big risks around flames. Little kids, bulky ungainly costumes and flames are a disaster waiting to happen. Teenagers, curious or looking for trouble pose different problems when flames are involved. Other venues, such as theaters, indoor shows and up-close audiences all present risks when chemical or flame effects are used. Also, many effects generate smoke, which can be problematic indoors, especially if smoke isn't what you were going for.
Chemical effects come to down to four main categories, flame, flash, fog and smoke. Each one can be created in more than one way, the primary goal should always be safety and control. You can make a great flame with burning gasoline, but control is difficult. You can simulate a flame with lighting, reflective foils or silks and a fan. That would be very controllable but it isn't very realistic, especially up close. But if you have to choose one, go with the safer, controllable effect.
Flame effects are most readily created with propane gas. Propane is flammable, but only with the correct fuel to air ratio. It is widely available and can be operated with readily available equipment. It can be stored in a variety of sized portable containers and is easy to work with. It can be conducted through a variety of piping and tubing and can be remotely ignited with electrical valves and igniters. For venues where live flame is acceptable, propane is reasonably safe and controllable. See our flame section for more information.
Flash effects are created with fast burning powders or with light. The classic "flashpot" is a small container such as a coffee can loaded with a tablespoon or so of flash powder, a very fast burning gunpowder and is ignited electrically. The flash can be augmented with lights or a strobe. Another dramatic flash is created with lots of intense lighting briefly flashed toward your audience. This can be done with various floodlights or with strobes. See our flash section for more information.
Fog effects are typically created by one of two methods, dry ice fog and glycol chemical fog. Dry ice fog creates a low lying fog that hugs the ground. It is created by placing dry ice into warm water. It releases its CO2 as a fog which quickly dissipates. For a longer lasting fog a chemical fog is a better choice. It is also a more controllable effect. It also has the versatility to fill a room or to create a ground-hugging fog (with the aid of a fog chiller). Chemical fogs have the drawback of having some odor which bothers some people. Most studies show chemical fogs to be safe, but recommend that people with asthma and similar conditions avoid such fogs. See our fog section for more information.
Smoke effects are similar to chemical fogs, they tend to fill an area. They are not usually a good choice for use indoors. Because of the odor, the time to clear, possible fumes and the open flame, they are best suited for outdoors. When large volumes of coverage are required, a smoke effect is more effective than a chemical fog. While high volume fog effects can be achieved with specialized equipment, the smoke effect is more economical. See our smoke section for more information.