Whether it's Hallowe'en or you're just throwing a costume party, a fog machine is just what you need to create the proper atmosphere. A typical fog machine consists of an element to heat your fog mixture and a fan to disperse the fog. You can also make fog with just a candle. While you can create a variety of interesting fog effects with various mixtures of glycol and water, it's probably best to stay away from glycols, because some of them, such as ethylene glycol (anti-freeze), are poisonous. You don't need them anyway, because you can make an effective fog mixture with store-bought glycerine, which is perfectly safe, and distilled water.
TL;DR (Too Long; Didn't Read)
Make fog fluid by mixing distilled water and vegetable glycerine. The total glycerine concentration should be between 15 to 30 percent.
Round up the Ingredients
You'll need four items to create your fog mixture. The first is a container in which to store it, and an empty 1-liter plastic water bottle works well. You'll also need a measuring cup to ensure you mix the ingredients in the proper proportion. The two other items are the ingredients for the fog juice. One of these is vegetable-based glycerine, which you can find at any drug store. You'll need a small 6-ounce container to make enough juice to fill your bottle. The other ingredient is distilled water, which is also available at drug stores. You don't want to use tap water or mineral water because both contain impurities that will clog up the fogging machine.
Mixing the Fog Fluid
The procedure for making your fluid is uncomplicated, but for best results, it's important to get the proportions right. You want a 15 to 35 percent glycerin mixture. The more glycerin you add, the denser the fog will be, but don't overdo it, or you might not get any fog at all.
Measure 2 Cups of Distilled Water
Pour the water into the plastic bottle. If the bottle held juice or anything besides water before you emptied it, you'll want to make sure you clean it thoroughly.
Add 1/2 Cup of Glycerine
This amount of glycerine creates a solution with a glycerine proportion of a little more than 25 percent. If you want light fog, reduce the amount of glycerine to about 1/3 cup.
Shake It Up
Put the cap on the bottle and shake the bottle vigorously for about 10 seconds to ensure the water and glycerine mix. The water should turn uniformly cloudy.
Pour a little bit of the mixture into your fogging machine and turn it on. Increase the amount of fog juice (after turning the machine off first) as needed. The fog may look like smoke, but it isn't. It's a suspension of tiny particles of water vapor and glycerine that will disperse into the room and eventually settle out harmlessly.
- If the fog has a "burnt" smell, you're using too much glycerine.
- Using a homemade mixture in a commercial fog machine will probably void the warranty on the machine.
Other Ways to Make Fog
If you don't have a fog machine, you don't have to go without fog. Just put some dry ice in a styrofoam container and add hot water. Be careful when handling dry ice, though. It's cold enough to give you frostbite, so wear gloves, and don't let children or pets near the mixture. It also creates extra carbon dioxide in the room, especially near the floor, so use it only in well-ventilated spaces and do not place the container near places where people will be sitting on the ground.