spreading fog

[moojoe]

this idea makes perfect sense to me, but i figured i should ask anyway.

im going to need to essentially coat the stage for one show in fog for a single scene, to do this, i really need fog coming out all over the stage, but due to budgets, can only get two fog machines.
my idea for this was to run PVC piping along the stage, drill holes every foot or so, and connect a fog machine to either end. when i turn them on, it will fill the tube, and work its way out of the tube. does anyone see this as a viable solution? i know that i need to keep the piping away from the tip of the machine due to heat, but that can be worked around.

[Arez]

The idea that we used fire extinguishers last time we needed fog comes to mind. I think we had about 4, so we used them and it was cheaper then the fog machines.

[Peter]

Becareful about using fire extinguishers..... there are alot of regulations and saftey considerations to be considered before using them (search arround the forums for previous topics abou this).

Do you want a layer of fog that stays low accross the stage or a wall of fog that floats up from accross the stage. Unless you cool the fog, it is going to want to rise as soon as it is out of any pipes. CO2 (dry ice fog) sinks b/c CO2 is denser then air.

[Mayhem]

I strongly recommend against the use of fire extinguishers for any purpose other that extinguishing a fire.

One thing you may need to add into your system is a couple of fans. Depending on how big your stage is and the length of the tubes as you may find the smoke leaves the tubes before it reaches the middle.

I have used some 4” computer fans before with fairly good effect in spreading smoke. I made up some small boxes so that a short length of 4” tube can be joined to a second length using the box. The only draw back is that the fans do not last too long as they foul up from the smoke.

The other way is to introduce the airflow without running the smoke through it. This can be done by using a “Y” connector. These connectors are essentially a straight section of pipe with a second section introduced at an angle. A bit like this:

____/____ only the angle is more acute.

This then allows air to be introduced in the same direction as the smoke will flow and doesn’t give the same problem of fouling up the fan.

You can also make the Y section out of metal and use a heat gun to make smoke rise quickly if needed.

[moojoe]

it doesnt need to be low lying, i actually want to fill the entire stage with it. the fan idea is a good idea.

and i would never use fire extinguishers, not only is that dangerous, its just...theres a lot of things wrong with that.

[Eboy87]

At my theater, before my time, they did Little Shop of Horrors. They did an effect similer. I believe they had two smoke machines on either side of the stage, and they hooked fans into the dimmers, controlled by the scenemasters on the board, to move the smoke where they wanted. From what I understand, it worked really well.

[LDSFX]

I have done this effect for several shows, the most recent being Les Miserables 2 years ago. We just used two fog machines, one SL and the other SR. If they both have enough power (like a LeMaitre G300) and you turn them up at full power at the same time, they will more-than-adequately fill your stage.

[foeglass]

Our school wanted to fill the whole stage with fog and came up with the idea of using theair ducts. These are usually a source of many problems in dealing with haze, but we ended up using it to our advantage by hooking up a hazer inside the actual air duct on the side of the stage.
___________
|----------------|
|__(hazer)__|

^^^^^^
the hazer sat inside this air duct


Because it was a hazer, it was much lighter and floated well above the stage so we had to direct with our best friends duct tape and cardboard, but with a fog machine this problem should be eliminated.

[The_Guest]

Have you considered experimenting with a low level liquid-nitrogen system? It's amazing how easy it is to manipulate and eliminates the hassles of dry ice. Sounds like dry ice or liquid-nitro would be you're best option, because the typical fogger isn't going to coat the stage like you like. Foggers typical tend to be ambient, because that essentially what fog is. Theater often requires you to exagerate to convince your audience. So, sometimes a mildly/cloudy room isn't enough. I always like a thick low-level fog combined with a light and ambient atmospheric fog (haze even works sometimes) because it makes it obvious that it's foggy but doesn't cloud up the acting space making it hard for the audience to understand the actors visually/physically. Also a foggy background combined with these things can help, but it's very tricky and hard to pull off. I'm not much of a fog expert anyways.

So it'd sugguest experimenting with different fluids, that is if your machine permits it. So contacting the manufacture of your machines would probably help. LeMaitre, Gem, etc should offer you different methods and fluids to help you get results.

[img]http://msnusers.com/_Secure/0SwDvHBIWITD*YTg8qhlrljchIXTQxN4uLQaf9CV*J5X!zRCfm cXIxFeMO3hmIRgzbL7WDHOSoMe!88L*6zr3nztYoBOGz1DA3or 7OSQlq5LT66epL!KxZg/DSC03369.JPG[/img]



The system used here creates a thick low level fog by dispersing lidquid nitrogen. In this particularly picture it's been used for a production of Fiddler on the Roof. For those of you who are familar with the show, it was used in the "Dream Scene" when Frumah Sara returns from the dead to haunt Tevye and his wife. Anyways, the outputs of the system are attached to a ventilation system that is routed allover the interior of the set to a series of hidden vents throughout the exterior of the set. When this system is activated it will completely cover the downstage area in front of the set with a thick low fog no taller than a yard. Once the downstage area is covered the fog will float its way off the stage, falling into the house and orchestra pit.

Even if you don't have a set to hide pipes or ventilation hoses (like the ones hooked up to the output of a dryer), you can still route them around the acting area. You could even route it throw the acting area, provided that you'd make the vents/pipes/hoses visually friendly from an audience perspective.

[Dale]

Originally Posted by moojoe

this idea makes perfect sense to me, but i figured i should ask anyway.

im going to need to essentially coat the stage for one show in fog for a single scene, to do this, i really need fog coming out all over the stage, but due to budgets, can only get two fog machines.
my idea for this was to run PVC piping along the stage, drill holes every foot or so, and connect a fog machine to either end. when i turn them on, it will fill the tube, and work its way out of the tube. does anyone see this as a viable solution? i know that i need to keep the piping away from the tip of the machine due to heat, but that can be worked around.

Thaty's funny. I always wondered if that would work. Just never had the time to do it really.