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 Dry Ice is frozen carbon dioxide (C02 at -109.3 °
F) opposed to regular ice which is 32° F. Unlike regular ice, Dry Ice doesn't melt - it
sublimates, the process of going directly from a solid to a gas.
Dry ice can be used many ways for Halloween but
always use with caution! It can cause very bad freeze burns which are
very painful and can permanently damage skin.
For most people the equipment needed to manufacture their own dry-ice is
simply too expensive. Dry ice can be found at most Ice Suppliers and Ice
Cream shops and isn't that costly. We pay about .75
cents per pound at a local ice supplier. It's much easier to buy than to
make but we just thought you might like to know how it's made anyway so
here goes. The first step in making Dry
Ice is to turn the carbon dioxide gas into a liquid. This is done by compressing the C02
and removing any excess heat. The C02 will liquefy at a pressure of approximately 870
pounds per square inch. Next, the pressure is reduced over the liquid carbon dioxide by
sending it through an expansion valve. Part of the liquid sublimates, causing the
remainder to freeze into snow flakes. The Dry Ice snow is then compacted together under a
large press to form blocks.
Dry Ice will sublimate (change from a solid to a gas) at a
rate of 10 pounds every 24-hours in a standard insulated container. The more Dry Ice you
have stored in the container, the longer it will last. This means it's important to pick
up your Dry Ice as close as possible to the time you will need it. It should be stored in
an insulated container like an ice chest to slow the sublimation rate. Refrain from
opening and closing the insulated container as much as possible. When you remove items
from the container fill the empty space with wadded newspaper. Any
"dead-air-space" will cause the Dry Ice to sublimate faster. Do not store Dry
Ice in your refrigerator freezer. The extremely cold temperature could cause your
thermostat to turn off your freezer.
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DRY ICE
SAFETY
 Never handle dry ice with your bare hands, it can cause
severe freeze burns! Always use gloves or tongs. If using large amounts of dry ice indoors or in
a closed area allow for plenty of ventilation. As it sublimates the dry ice releases it's
carbon dioxide which living creatures, like us, shouldn't breath. Do not store Dry Ice in
an air-tight container without proper ventilation, the carbon dioxide gas will cause any
airtight container to explode. |
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FOG MAKING WITH
DRY ICE
 To make fog from dry-ice you
simply add pieces of dry-ice to very hot water. One gallon of hot water for every 1 - 2
pounds of dry ice is one formula. The variables of fog generation are the water
temperature, amount of the dry ice and the size of the dry ice being used. The smaller the
size of dry ice pieces the more fog, the higher temperature of the water the more fog.
When the water temperature gets below 40° F, fog production will stop and you will need
to change the water. But be warned, it takes a lot of dry ice to produce the
same quantities of fog as a small fog machine.
 One way to make a very simple
dry-ice fog generator is to use a Crock Pot as the heating tank. This works great for
placement behind a tree, headstone, crypt, etc. Unless you have a Crock Pot that just
happens to be black or other dark color that will make it easily cancelable, you'll need
to paint it black. Start by cleaning the surface of the Crock Pot so that the paint will
stick. Remove the ceramic cooking pot and selector switch. Mask off the heat control
indicator with masking tape. Now spray the Crock Pot. Once the paint has dried thoroughly,
put the cooking liner back in. Do not try to use this without the liner in. Doing so could
cause electric shock and/or a fire hazard. We use a metal deep-fry basket to hold the
dry-ice. While this method does work and will extend the time the water stays hot, the
heating element in most Crock Pots are not designed to get that hot, so you will still
have to replenish your hot water, although not as often.
MISTING PUMPKIN
  This is a very
cool looking effect!! After carving your pumpkin or
using a foam one, use a light stick or battery powered light inside for internal
illumination (never use an AC powered light). Place a clear plastic container with hot
water inside and add dry-ice. You cannot use a real candle as the carbon dioxide will
extinguish it.
Making
Dry Ice
 Some
towns, particularly small ones often don't have dry ice available at the
local ice company or the cost is sometimes high. But there is a
solution! The Cole Parmer Dry Ice Machine allows you to make a one pound
block of dry ice in just sixty seconds and will produce
between nine and eleven blocks from a single fifty pound
tank of liquid CO2. The machines are simple to
use—connect a CO2 cylinder to the dry ice machine and
open the regulator valve. As each ice block is made,
just release latches and lift out block. Dry ice blocks
are ready for use just as they come out of the machine.
You will need a local source
for liquid CO2. Available at
coleparmer.com |
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