Smoke effects for Oz

I know Oz has been covered, I read all the posts. I have a specific question.

Is it possible to use something like a Chauvet Geyser or similar and direct smoke "explosions" to parts of teh stage through PVC pipe for dramatic effect on witches entrances? Will the fog from a machine like this travel trough a few angles and turns of a PVC pipe routed under scenery?

Just thinking outside the box....

Doug Lowthian said:

I know Oz has been covered, I read all the posts. I have a specific question.

Is it possible to use something like a Chauvet Geyser or similar and direct smoke "explosions" to parts of teh stage through PVC pipe for dramatic effect on witches entrances? Will the fog from a machine like this travel trough a few angles and turns of a PVC pipe routed under scenery?

Just thinking outside the box....

Click to expand...

I'll begin by tossing a few queries your way:
What diameter pipe? Three or Four inch possibly?
How long with how many bends totaling how many degrees of bends in total?
Would you have a fan establishing and maintaining a worthwhile air-flow through the pipe for the duration of the performance and cue / add smoke at the intake end as required and sufficiently before you need the smoke to appear?
Tag! Your turn.
Toodleoo!
Ron Hebbard.

Generally, yes. It takes some experimentation and you may not get the "explosions" of smoke, but you can duct fog fairly successfully. I've always found that a gap between the nozzle and the pipe end works best but YMMV!

Ron: No idea! Right now I'm just at the idea stage. We don't even own the machine but am thinking of getting one. I'm imagining maybe 2-4 inch pipe, as few bends as possible and as short a run as possible. Fan a possibility (maybe a jury rigged computer fan in a y type arrngement so as not to blow fog through the fan? No idea til I start experimenting but I thought I 'd throw it out and one of the bright people here would say either "This is how you do it!" or "Are you crazy!?"

Doug Lowthian said:

Ron: No idea! Right now I'm just at the idea stage. We don't even own the machine but am thinking of getting one. I'm imagining maybe 2-4 inch pipe, as few bends as possible and as short a run as possible. Fan a possibility (maybe a jury rigged computer fan in a y type arrngement so as not to blow fog through the fan? No idea til I start experimenting but I thought I 'd throw it out and one of the bright people here would say either "This is how you do it!" or "Are you crazy!?"

Click to expand...

I suspect you'll find a fan somewhat a necessity. Most fog machines aren't designed to propel fog much further than their nozzles can spray.
A parallel thought's crossing my mind. Back when distributed sawdust suckers began appearing in North American home shops, most of the piping was black whereas the Europeans were ahead of us with clear piping with minimal impediments to air and dust flow. The clear pipes and bends offered the HUGE advantage of being able to see where any blockages and buildups were occurring. Not that this has anything to do with blowing smoke, it was just a thought that passed through when you got me to thinking about blowing smoke. I've seen people use Y's with a fan constantly blowing air in one side to establish / maintain a flow adding smoke as desired in the opposite side and I've also seen folks firing smoke through fans. With oil-based foggers, you don't have much worry about lubricating the fan. Establishing and maintaining a good airflow is a large part of making this work. I think you'll need something considerably 'butcher' than a computer fan, something that really moves some air without being too noisy. Perhaps something from an auto wreckers? A small centrifugal blower and aim smoke into it from a few inches away? Think the sort of blower that clears your windshield and think of it running slower than maximum speed to hold down noise. You can blow smoke through squirrel cage centrifugal fans without blowing smoke directly through their motors. it's also not too difficult to vary their speed. Sweep bends are your friends, avoid hard nineties.
Edited to add a missed word.
Toodleoo!
Ron Hebbard.

If your big into build it yourself you could make a few of these and put them inline with the pipe.

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As far as a fogger I would go with what can output the most continuously that fits in your budget.

My first was a home made dry ice machine: 55 gal drum fitted with an electric heater (farm supply - water trough); casters; a ply lid with a squirrel cage fan on it (to presurize the drum); a cage for dry ice I could plunge into the water; and two dryer vent hoses out of the drum. Worked exceedingly well for years. I think people see it now and look at it like I use to look at an Olivetti. You might find some principles here that work.

Cheap and easy - CO2 fire extinguishers. Very directional. Kind of wonder if you could extend the hose on it already. Local refill places almost always near.

I actually just did this exact thing, we used it for the wizard effect and for the Witch's entrances/exits. We used 2 ANTARI W-715X units (they get about a 20ft up spray) that we placed underneath a 6ft high platform and used PVC pipe that was just laying around the shop (I want to say it was about 3" dia.) to plumb it up and divide it into 4 jets each (8 total) to create a sort of smokescreen. We also used quick dissipating fog and it didn't interfere with the rest of the scene beyond when the fog was actually being used.
The Antari units can be controlled by DMX or by a wireless remote. We opted for the wireless remote and didn't have any problems with controlling the foggers through the facing of the platforms and from the very back of the theatre.

Fan-wise, I've had good experiences with air-hockey table fans for future reference. Just be sure that you get a nice seal with the fan with the pipe to get as much air in as possible. I'm currently thinking of ways of running an air tank for "huge" blasts of fog. Though the tanks would have huge volume, so will the foggers. I would actually like to experiment with it, however moving my 21 gallon air compressor won't happen anytime soon as it would involve me removing the oil then putting it back in for transport. But essentially, you would have a very fast stream of air entering from a hole cut into it and be directed in the direction of travel. Several of these high speed/pressure nozzles would make for some larger blasts of fog. Only issue is being able to maintain air if being used extensively in short periods of time. Another option is to still use a Y pipe, but instead of the typical fan, run the hose(s) through the "fan" end and seal that port with maybe expanding foam or something else.

I built a fog ducting system that consisted of 2' PVC pipe and some salvaged vacuum hoses. My main fogger is an Antari M5. The jet on the M5 is pretty powerful, the fog will carry a long way. THe hardest part of the assembly was finding the "Y" fittings, because I wanted symmetrical Ys. They aren't a stock item and I had to really search for them, finally locating them at a shop that specializes in koi ponds. I'm told that hot tub dealers may also carry them. That being said, the Geyser is a fun unit to play with. I've used them for great effects with the band. I programmed a scene in my controller that included a burst from the Geysers (we have two that are linked). On certain songs, I will call up that scene, usually only for a second or less. The resulting burst somewhat resembles pyro, plus if you are using a lighter fluid, it adds atmosphere that dissipates rapidly.

I think Bill is on the right track with the Dry-ice fogger.


When we did this show in a high school, I borrowed a Dry-ice fogger (as Bill describes, but no fan required, the sublimating C02 forces the fog through the pipe with more than enough force) from a local college. It was a 50gal drum, with water heater elements, and a basket that could be lowered into and lifted out of the water.

If you want to purchase your own (rather than borrow or build), I'd recommend something like the Chauvet Nimbus (with the cart to move it around easily). And get a dryer hose from your local big-box store. You can run this off of a single 15amp circuit breaker (and it does not need to be powered after the water gets to temperature). Some of the larger machines require multiple circuits, which is great, if you have them, but for a small, controlled effect like this, a machine this size is more than adequate.
The effect is nearly silent (so you can have whatever sound effect you want), and it was easy to set-up and run... plus the kids loved having dry-ice around.

The effect looked incredible. We used a student stagehand to basically wave they dryer hose around (at ground level, pointed upwards) as the witch entered (the amount of fog easily covered the entrance), which caused a huge plume of fog, because the water was at it's hottest. After her entrance we lifted the dry ice out of the hot water (which mostly stopped the fog), and the remaining fog settled to the ground, and slowly dissipated... which looked extremely spooky and menacing, got oohs and aaahs from the audience, and was easy to operate.
For the melting bit at the end of the show, we kept the fog low, and she settled to the ground under it, and then slipped offstage, leaving behind a robe and hat which held the fog for about an extra 30-45 seconds, and gave off little poofs as the other actors poked it.

For both the entrance and exit she was adjacent to scenery, so could easily enter and exit without being seen.

The effect was neat enough that the director wanted to use it in the Haunted Forest, as well. the big issue was allowing enough time for the water to re-heat between cues.

-HTH,
Ford