Dry Ice smoke machine

[zac850]

I was wondering if anyone had any experience with a Dry Ice smoke macheen. I am curious to know how fast they can fill a small-medium size stage with smoke. I was thinking of useing a normal smoke macheen, but the problem is the smoke would never disapate given the ventelation of the room.

Also, how much SOULD it be to rent and/or buy one, as well as how much sould the dry ice cost? Also, is there anything else I sould know? I was planing on having it downstage center for the entire show, with an extreamly long control cable so it can be controled from back stage (or, if one of them comes with a remote, from the booth).
Anything that would help me set-up, use, purchase a dry ice smoke macheen would be very helpful

Thanks
Zac

[digitaltec]

I have used a dry ice machine for a few productions including the Nutcracker. If you want low lying "fog" they work great. they also have different types of fog or haze that do the same thing for a much cheaper price. Rosco Stage & Studio Fluid for a fog machine is designed for fast dissipating and ideal for chilled low-lying effect. In terms of price...

Buying:
Dry Ice Machine: $600- $4,000; depending on features and capacity.

Fog Machine: Rosco Alpha 900 and an a liter of fluid; $450

Renting (Estimates):
Dry Ice: $225 per week plus dry ice

Fog Machine: $60 per week plus fluid

(These Prices came from my Vincent Lighting and BMI catalogs for 2004.)


From what I have seen with the Rosco fogger, it does the job pretty well for this type of effect. Now all you have to deicide is what your budget allows. So, I hope that helps out a bit. Have a great day.

[wolf825]

Dry Ice machines are fun toys...There are a couple of ways low ground fog can be made--by use of Dry Ice alone, by use of dry ice and a fogger, and by the use of C02 in addition to a fogger. Depends on if you want a unit that is strictly one thing--like Dry Ice only, or a unit that can be flexible to be a fogger one day, a dry ice ground fogger the next.

If you already have a fogger, you can build your own attachment for the fogger out of a cooler & dry ice to add to the front of almost any fogger that will make it a chiller unit and give you low-ground fog same as a dedicated dry ice machine will. In a pinch you can also use the cooler method and add regular ice if dry ice is scarce--but the effect is not as good but will work in a pinch. Can't do that with a Rocso chiller--you drop regular ice in the hot water all you get is steam. If anyone is interested in this home-made method to add to a fog machine they already have, I will post the how-to's. Just speak up...

Another consideration if you want thick fog you can control better then the dry ice, and also will get you longer service then a standard dry ice fogger will, you may wish to check out products like the LSG from LeMaitre (LSG=Low Smoke Generator). An absolutely GREAT unit--uses a 300lb duer of C02 that will last you a good long while, and overall is cheaper to stock and supply then buying repeatedly dry ice for a show. Depending on how heavy it gets use--1 duer of C02 can last a full show run of a week or more. Also--the fog is colder by the use of liquid C02 and the dissipation of the fog is thorough. Its thick, dense and doesn't rise above the knees and can get almost a foot deep if confined. As soon as it starts to rise--its gone with no residue or smell. Great toy--cost is about $3k for the entire unit...and as a bonus the fogger that LeMaitre supplies for the LSG also doubles as a regular fog & haze machine you can use without the chiller. Its like buying a fogger, hazer and a chilled ground fogger in one buy.

hope that helps...
-wolf

[zac850]

hum, ok, so now my difficulity:
I need to have basicly a screen of smoke, so that the witch can change form a hidious witch to a beautiful woman. I would LOVE to be able to also have a low lying smoke area, so that when we have an entrence/exit we can have some cool fog, but for now the most important thing is this smoke screen, in center stage. I was thinking of situating the macheen in center stage, with a long control so that it can be controled from back stage. I need to be able to fill up part of the stage with smoke fairly quickly, and I need it to disapate fairly quickly.

The entire budget for the show is 3,000 dollars, but that includes costumes and everything else. This budget roles over, so whatever is left over after this show goes to the next show, so i would like to save as much as I can, if at all possible. However, this is a necisity for the show, and will also be really cool...

[wolf825]

ahh...the smoke "screen" or wall effect.. Well since warm smoke will always want to rise what you want to do is make it cold fog--so that it falls and sinks to the floor. If you pop your fogger up in the grid area and shoot it off without chilling it all you will get is puffy smoke that won't sink or settle and won't make much of a screen. Solution to this is to "pipe" your fog from the cold CO2 or dry ice machine. Use capped PVC pipe and a T attachment, about 4 inches in diamieter. You can also use Dryer hose as well instead of PVC for travel. Basically you want the fog to be piped to the center of the pipe and spread downward--the pipe will have slits cut in it to allow the fog to "fall" in a curtain effect. if you have capped the ends you should get fog only in the areas with the slits. Heavy dense cold fog will work best--but keep in mind the higher up you have to mount the pipe and the farther away from the pope the fog source is, the thinner the fog will fall. usually if you can do this over a door or set piece that is closer to the actor and stage the better the effect. Either that or you would need a heavy fog producer.

Basically it works like this:

[fogger cold flow]----pipe or drier hose-------{ s c r e e n p i p e }

Couple of tricks to this have to do with pressure and force to get the fog to go "up" and thru the pipe with enough thickness and force to keep it moving--usually accomplished with a PC fan mounted inside the hose or on the front of the fogger. Make sure your edges are sealed so you have no leaks. Another key--is not to make the holes right where the fog enters as large as the ones on the outside--else all your fog will want to travel thru the first holes it finds and not travel evenly. Have to play around with this but I suggest smaller holes at the site the fog enters the capped pipe.

hope this helps...
-wolf

[zac850]

Ok, so let me try to make sure I understand this:

have the fog macheen on the ground backstage, have some pipeing going up to the top of the stage, have a pipe on the top of the stage and there we have holes that go from biggest to smallest.
that much I can do. My question now is what type of fog macheen to use (dose it matter, is there a type I souldn't use) and what type of fog juce if its a macheen that needs juice. As I said before, I want a smoke wall, that will disapate quickly after I turn off the fog macheen

Thanks
Zac

[wolf825]

In a nutshell, you will need to make sure you have some fans to help pump the airflow to get the fog to actually flow thru the pipe and go upwards--it can be quite a challenge. Ideally if you could mount the fogger or dry ice machine from up top etc and drop the hose down--gravity would be your friend. If not--PC cooling fans mounted inside the pipes or tubes help a great deal. As for what kind of fog--if you use juice fog it will be hot--so you will need to cool it or as soon as it come out it will be a cloud.. cold fog is best--either cooled from Dry Ice or from C02 so that as it falls it goes to the floor and not hang in the air. dissipation is left to the fog you use--and if you use a fast dissipating fog fluid and then cool it with dry ice, it will help. If you are just going to use dry ice or C02 based fog--it will go away the fastest.

-wolf

[zac850]

Ok, got it. Thanks, this will proubly be the coolest effect that my school has EVER done!!! I'll try to remember to post some pics of it once we get it up in 3 mounths!!!

im really excited...

Thanks a lot
Zac

[ship]

With Wolf's train of thought is a possible solution for how to cool that fog stuff. With dry ice you might try drilling some 4" pipe holes thru a soda can/camping cooler. Dry ice is in there and the smoke has to travel thru the cold environment - especially if the holes don't line up to get out. Pressure will help that happen also the fan. This cooler also provides a convient place to mount the fan.

Also if the burst at first is what you need, or at least what you need at any one point, when you turn the machine up to full than that burst should be of sufficient power to fairly well pass by the cooling unit and get out as if a cloud of smoke. That way you can get that localized burst of smoke when the fan and smoke machine are at full, yet for more normal moments gain the benefit of the chiller machine.

Might be able to rent such chiller machines also without having to manufacturer them. Of note on the cooler would be to situate the blocks of dry ice (most ice cream stores sell them) so they actually hit the smoke instead of just lie at the bottom while the smoke passes over the top.

[wolf825]

Originally Posted by ship

Might be able to rent such chiller machines also without having to manufacturer them. Of note on the cooler would be to situate the blocks of dry ice (most ice cream stores sell them) so they actually hit the smoke instead of just lie at the bottom while the smoke passes over the top.

I find its just the same money to buy a cooler and make your own then it is to rent a dry ice chiller to go in front of a fogger...and I usually build a "cage" type chamber inside the cooler that the hot fog has to travel thru the pellets or blocks before it can exit so you get a thorough cooling of the fog.

-wolf