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Dry Ice for Dummies!

Discussion in 'Special Effects' started by iandy, Sep 20, 2007.

  1. iandy

    iandy Member

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    Hey

    I would like to use Dry ice in the next production I am doing, but I have very little knowledge of how Dry ice machines work and would really appreciate if someone could answer these few questions.

    1. What would be an ideal machine for a black box studio (sorry haven't got measurements to hand), if possible between a 'Cumulus' and a 'Pea Souper' as that's what our local hire company offer.

    2. How much does one machine hold of dry in Kg on average and how long would one container last say 60Kg of Dry Ice?

    3. How does the Dry Ice need to be stored?

    4. Are there any laws or Health and Safety issues I should know before using one.

    Look forward to the replies.

    Andy
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

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    I would say go with a pea souper, they cover extremely well. As far as storing it goes, the key is to keep air out of it. I usually put it in a paper bag, seal that in a plastic bag, then put that whole thing into a well insulated cooler then duct tape the cooler shut.
     
  3. BillESC

    BillESC Well-Known Member Premium Member

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    Footer,

    You are getting very close to creating a bomb. Dry ice expands as it sublimates. Enclosing it in a sealed enviroment can become explosive.

    The best methods of dry ice storage are insulation. You can use moving blankets, sawdust, or any other media that keeps air away from the surface of the ice and creates an insulation field.
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    I do vent it, but at the same time I try to keep moving air from coming in and going out. Its sealed but can still breath. I usually just open up the little drain the the cooler, which seams to work.
     
  5. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    I'm going to be purchasing a LeMaitre Peasouper for my 55 square foot black box. Many of the dry ice machines you'll see are the size of a larger barrel or garbage can. So the Peasouper is nice because it's significantly smaller and lighter for storage. True it doesn't have the massive volume of one of the big ones but for our smaller spaces you don't need THAT much. According to the website Peasouper holds about 20 lbs of Dry Ice and lasts about 5 minutes.

    Safety is VERY important with Dry Ice. Dry ice "fog" is actually a cloud of (EDIT) Carbon Dioxide. (EDIT) C02 is heavier than air so it will fill a low space and drive the oxygen out. So if you have a pit with an orchestra in it, dry ice fog will fill the pit and STAY there driving out all the oxygen... and killing your orchestra. Or if you have a LOT of dry ice fog pour into an audience same problem. Never let an actor hide, lay down, or pass out in a dry ice fog... as they may never get up again.

    As Bill mentioned be careful of sealing dry ice too tight, it is constantly giving off gas so it quickly can build up a lot of pressure... do a Youtube search for dry ice bombs to learn what not to do. (DON'T try it at home kids unless you like picking plastic shrapnel out of your face). For storage you want to insulate as much as possible while still allowing the dry ice to breathe.

    Finally you don't want to touch dry ice. It will give you these nasty little frost bite burns. So some heavy leather gloves are important to have around to handle it with (welding or cooking gloves would be great).
     
    Last edited: Sep 20, 2007
  6. Van

    Van CBMod CB Mods Premium Member

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    I Know you really meant to say Carbon Dioxide, But I thought I'd correct it for those in our audience who might not know.

    What Gaff say is true, however. Carbon Dioxide gas is dangerous in high concentrations, for extended periods of time.
    As for you original questions, for a "typical" fog effect in, say, "A Christmas Carol" You could get by with as little as a Kg at a time. I have found it is best to rent your machine a few days early run some tests and figure out exactly how much you need for any given show. Then only get 2-3 shows worth at a time. That way you reduce the loss to sublimation. I've worked show where as little as 20 pounds was needed per 4 shows, and we kept it in a small styrofoam container, to some shows where we were getting it delivered 1.5 metre square pallets which would get us thropugh one night.
     
  7. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Crap... it's been a long day with a set of sick 1 and 3 year olds... Let me just go edit that post.
     
  8. jwl868

    jwl868 Active Member

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    Metric units and English units mixed together in the answer - nice touch.

    By the way, gafftaper, is the area of your black box correct? [At 55 square foot, I get about 7' x 8'...]

    Joe
     
  9. avkid

    avkid Not a New User Fight Leukemia

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    That's like the size of my basement office.
    I might be able to fit six people in folding chairs if I tried.
     
  10. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    :oops:

    Well the budget was running a little short and we had to cut somewhere and I wasn't willing to cut shop tools or lighting so overall building dimensions (and my math skills) were the first thing to go.

    Yeah That's it... That's the Ticket! :cool:
     
  11. Van

    Van CBMod CB Mods Premium Member

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    Yeah, I'm Bi-dimensional.:mrgreen:


    Sure it's a small Blackbox, But think of the money he saves on Royalties, Lighting, Heating and Cooling, He can light the whole thing with a cliplight and cool it with a desk fan.
     
  12. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Actually it's good thing that it's so easy to cool because with 196 dimmers, 60 S4's, 24 S4 PARS, and 48 Fresnels, it's going to get hot in there... I'm going to need a lot of side arms.
     
  13. jwl868

    jwl868 Active Member

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    It's so small you can only show The Hunchback of Notre Dame....

    But seriously, I only pointed out the dimensions so that the original poster had a frame of reference.

    Joe
     
  14. iandy

    iandy Member

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    Thanks all the replies.

    I measured the studio and its 36ft x 36ft. but use about 2/3 for stage and 1/3 audience.

    So the peasouper it seems to be! Basically we have a music and singing show and was hoping to use it for a about 2 or 3 numbers in the show each about an average song length (4mins) and we are having 3 shows and would like to test it out in dress rehearsal.

    So how much dry ice would I have to order for the peasouper do you think?

    Also don't know if it makes a difference but im actually in London England as I have seen many of you are from US.

    Andy
     
  15. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    I think the biggest question is recharge time. You fill up the water, it heats up in the machine, drop in 20 pounds of ice and it lasts about 5 minutes. But then you have to reheat the water before you can fire it off again. The Lemaitre manual says it takes 45-60 minutes for the water to reach the proper temperature. I suppose you could drain the tank, and refill it with boiling water that you have standing by somewhere. I'm not familiar with the Cumulus (must be a British product) but, a little quick searching looks like it comes in two models one about the same capacity and one more than two and a half times the peasouper. Perhaps with the big one you could fill it up, run it 4 minutes, turn it off, wait, run it four minutes... repeat. Another website claims the Cumulus has "near continuous" operation, which I highly doubt. For maximum effect you need your water heated to near boiling, it would take an amazing heating system to keep the water warm enough to combat the chill of the dry ice for continuous operation.

    SO, I guess what I'm saying is to call your dealer and tell them you want three separate 5 minute bursts in the same show and find out if the one big Cumulus can handle that or if you need multiple foggers.
     
    Last edited: Sep 21, 2007
  16. Logos

    Logos Well-Known Member

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    When I was living in the UK (I left in 2003 and I now live in God's own country Australia) Dry Ice was really expensive and quite hard to get. I only used it about twice then went over to refrigerated low smoke machines. Check with LeMaitre about the supply of dry ice. You might be better off in London than I was out in the deepest wilds of Kent.
     
  17. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    You might also want to do a check of heinous crimes committed by one Tony "Logos" More in late 2002 or early 2003. It would be interesting to find out what got him banished.
     
  18. Logos

    Logos Well-Known Member

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    Moi? Banished? I had to sneak out under cover of darkness or they would never have let me leave.
     
  19. David Ashton

    David Ashton Active Member

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    Sorry to be pedantic yet again but the statement that fog is carbon dioxide is not correct, the dry ice is the cold interface which condenses the water vapour from the boiling water into fog.It is water fog, it is wet, it will make the floor wet and instruments wet and amplifiers wet.While there is of course an increase in co2 levels I have never seen it effect anyone, so in a normal venue with basic ventilation there is not a problem, however there is a definite "getting wet" problem.
     
  20. Van

    Van CBMod CB Mods Premium Member

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    The "Fog" itself is condensed water vapor or vapour, if you prefer. The agent for causing the condensation is Carbon dioxide gas, which, having recently sublimated form its solid form is extremely cold. While you are correct in saying that the "Fog" is not CO2, you are incorrect to imply that there is no CO2 in that Fog. It is the presence of cold CO2 gas that keeps the condensation condensed.
    You may never have personally seen it effect anyone, however there have been several cases of individuals who have passed out, waiting to make an entrance by crouching/laying in a thick cloud of "fog". It typically take an exposure to 20% or higher approximately 10-15 minutes to kill a human being, however exposure to concentrations of merely 10% can cause unconciousness, vomiting, and visual imparements is as little as a couple of minutes. Now will an actor, or muscian standing in the center of the stage expirience ill effects ? Most likely not. Will the Kid playing the ghost of Hamlets father, who is hiding behind a gravestone, waiting to make his appearence experience an increase in headaches, heart rate, difficulty breathing, it's quite possible.
     

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