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building a dry ice fog machine

Discussion in 'Special Effects' started by johnnayb, May 23, 2006.

  1. johnnayb

    johnnayb Member

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    Hello--does anyone have experience/ suggestions for building a dry ice fog machine? We need enough fog to cover a medium sized stage rapidly and maintaining the cover for about 5 to 10 minutes? Based on the fact that we perfere low lying fog, want the fog to dissapate quickly, and have a low ventilation system, I perfere the dry ice option.

    Thanks,

    Johnnayb
     
    Last edited: May 23, 2006
  2. cutlunch

    cutlunch Active Member

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    If you look at commercial dry ice machines they are fairly simple to make. You maybe able to get someone to make you one.

    They are basically made from a steel drum. With a lid,probably hinged so it just siots on top. This is in case some idiot blocks the outlet. An outlet pipe is welded to the side. Make sure this outlet is never blocked.They have a water heater element inserted in them to heat the water. The dry ice is put into a metal basket that can be raised and lowered into the water. When you need a quanity of fog the basket goes into the water.

    Here is link I found where someone has built there own fogger. It might also give you some ideas.

    http://home.paonline.com/joespuppets/1-fog.htm

    edit: Just found this link that shows a number of ways to combine foggers with dry ice to give low lying fog.

    http://wolfstone.halloweenhost.com/HalloweenTech/fogchl_FogChiller69.html#DeathLordFogOnTheRocks2000

    A google search finds many links to this topic.

    Just remeber safety first especialy if you go for an electric setup with the water around. Also the stage can get wet from the condensation caused by the dry ice fog.
     
    Last edited: May 23, 2006
  3. BillESC

    BillESC Well-Known Member Premium Member

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    I was half owner of F & B MFG. back in the 70's during the Disco craze. Our only product was dry ice fog machines and we built and sold several thousand.

    You'll want to start with a 55 gallon oil drum with a epoxy phenolic lining. You'll need to install two 1500w domestic hot water heater elements near the bottom of the drum and they should be fused or circuit breakered as well as switched. In the lid of the drum you can install two or three 4" PVC output couplings and a 465 cfm squirral cage fan and a one 1" diameter flange. The flange will hold the metal rod that holds the drop basket.

    This machine which we trade marked as the "Fog-it" fog machine will produce in excess of 40,000 cubic feet of fog in the first two minutes (with a 150 lbs. drop of chopped dry ice.)

    Feel free to call me if you'd like more detail and a few hints...
     
  4. Chris15

    Chris15 CBMod CB Mods Premium Member

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    As with anything, remember the safety aspects cannot be neglected. You are mixing electricity and water, so you would want to ensure that you feed this from a RCD / GFCI. You don't want it to become like this person.

    Remember also the risks associated with dry ice and the need for ventilation etc.
     
  5. Peter

    Peter Well-Known Member

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    Also, remember never to seal the dry ice in a container with no ventallation. As the dry ice turns into a gas it expands and any expanding gas can turn explosive if contained. (My AP Chemistry teacher demonstrated this rather violently with dry ice and I dont want you to in advertently do that experiment he did because it could easly cause great harm)
     
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  6. DarSax

    DarSax Active Member

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    I got this through one of the links that cutlunch posted, but

    http://ghostsofhalloween.com/projects/fog_chiller/

    Seems like a pretty good idea, especially since its a fairly simple way to build an effective one. Not to mention you can easily use regular ice with it, and as long as you take special care to seal up your holes, you shouldn't have any problem at all with leakage/electricity.
     
  7. saxman0317

    saxman0317 Active Member

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    At school we just put it in a shop vac and duct tape all the connections. Lid seals great and tight, and the plastic holds up well
     
  8. CHScrew

    CHScrew Active Member

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    I have the plas for a Dry Ice Fogger attached. The plans are fairly simple.

    There is only one major problem people run into. When you heat the water that you're putting the dry ice into, don't turn off the heating element when you put the ice in. If you shut off the heat the ice will cool the water very rappidly and your fog effect will only last a few seconds. Make sure you keep the water heated the whole time.

    Oh yeah, it doesn'y show it very clearly in the pic. Actually it doesn'y show it at all. But the bottom of the drum is filled with water up to a little under the whole for the fog hose. This is the water in witch you submerge your dry ice into.


    TIP! - I've found that these machines work a lot better if the dry ice is broken up into small pieces, rather than one large chunk in the basket.
     

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    Last edited: Jul 31, 2007
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  9. KrazyKatt

    KrazyKatt Member

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    This sounds like it would be perfect for what I am looking to build. But the cost of dry ice is a factor. How much dry ice would be needed to produce for for a 10min scene? Would I need someone feeding dry ice into the barrel as the scene goes?
     
  10. Van

    Van CBMod CB Mods Premium Member

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    I SO wish someone would come up with a formula that would tell you exactly how much dry ice you need for a given fog effect for a given amount of time. There are, however, so darn many variables. How deep, how big a space, what's your HVAC flow like, how far from the area of effect will the dry ice machine be located. My advice to folks who've asked me this question in the past has always been, buy twenty pounds and experiment.
    A trickle of fog over a ten minute scene might not take more than a pound or two. A knee deep pea-soup over the whole stage for the Witches scene of The Scottish Play will take a WHOLE lot more.
    Speaking of which: The longer/more fog you need the higher volume of water/hotter water you need. Sometimes a couple of smaller, 25-30 gallon, foggers are needed rather than one big one.
    I like using a small recirculating pump and a showerhead(s) in my Fog Machines to really keep the hot water washing down the ice rather than the immerse the ice completely in the water, style; Those tend to create a situation where a thin shell of water ice will from around the chunks of dry ice thus the fog will only come out in fits and spurt through little pinholes.

    Ok, sorry you asked what Time it was and I told you how to build a pocket watch.... If you need any other plans or if you have question on how to build one I'd be happy to advise. I'm sure there's got to be a place you can rent a machine, in Phoenix, just to experiment with.
     
  11. JD

    JD Well-Known Member

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    Probably 200+ pounds. Water temp drop would be the biggest problem, so you would be looking at 3 or 4 machines for a 50 x 30 stage. Dry ice also doesn't keep long, so you want to over-buy, especially if it is going to sit for a day or so. Storage is important. Several layers of newspaper, surrounded by foam peanuts and in a cardboard box. The whole thing should then be put in a large plastic trash bag to reduce airflow.
    Remember, you can get a very nasty burn off of the ice, so always wear protection when chopping it up to go in the machines.
     
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  12. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    And goggles to protect your eyes from flying chips.
    In our area, our best price and availability was from an industrial welding gas supplier who'd sell it in 50 pound blocks as well a taking a newspaper wrapped solid block, slicing it into 1" by 1' x 1' slices and adding an additional outer wrapping of newspaper prior to dropping it into a cardboard box and handing it to you. As has already been mentioned, DO NOT ship or store dry ice in tightly sealed containers as it sublimates directly from a solid to a gas with a greatly increased volume and becomes, essentially, a highly pressurized bomb waiting to occupy a much larger volume of space.
    Toodleoo!
    Ron Hebbard.
     

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