One of the ideas that we kicked around while brainstorming for the concert was to have a fog machine. We wanted to use dry ice, as opposed to a conventional smoke fog machine. Dry ice essentially creates a heavier than air cloud of water vapor and carbon dioxide that stays on the floor and looks more dramatic. Smoke machines make billowing clounds of smoke that flood the entire room and make it all hazy. I opened my big mouth and said I could arrange to get one. My original intention was to rent one from a guy who goes to my church back home. The guy owns a rental center that has basically everything, and he gives us discounts, so it seemed like a good idea at the time.
That night I went home and did an internet search on dry ice fog machines. That simple search started a long chain of events which I'm going to share with you, in hopes that you can benefit from what I learned mostly by trial and error if you ever need to build a dry ice fog machine.
Let's start with the basics. Dry ice is frozen (solid) carbon dioxide. It has the rare property of being able to truely sublimate, or go directly from a solid to a gas. Compare that to water (or 'wet' ice). You have an ice cube, and as it gets warm, it turns to liquid (water) that will eventually evaporate into water vapor (gas). Dry ice, as you can tell from the name, is dry. An ice cube of dry ice that's left sitting on a table or whatever, will not turn into liquid first. Instead it will just shrink until it finally disappears.
Carbon dioxide freezes at -110 degrees F. That's way colder than your typical freezer gets, so even if you put it in your freezer, it's still going to melt. So, in order to keep it solid and cold, the best way to is to just get yourself a good cooler, and accept the fact that you'll lose some during storage. (Roughly 5-8 pounds per 24 hours, unless you REALLY insulate it, in which case you'll lose less.) You need a styrofoam cooler, because plastic ones can crack at those temperatures. I scoured my house, but unfortunately I didn't find a cheap old styrofoam cooler.
I did, however, find a cardboard box...
