Make a Fog Chiller for $10

Fog machines are great for Halloween... but fog tends to rise up into the air, spread out, and disappear. If you do not have a very powerful fog machine, this can ruin the whole effect.

The solution to this is to build a fog chiller. The fog chiller cools the hot fog from the machine, causing it to stay low and billow along the ground.

This is a small fog chiller, which works well and is cheap. It takes an hour or two to build.

Step 1 Design and Theory

About Fog
The principles behind a fog chiller are the ideal gas laws. The warmer air is, the less dense it is, and therefore is pushed upwards by sinking cold air. Simply put, warm air rises, cool air sinks.

Fog machines work by pumping fog liquid onto a very hot "heat exchanger", which flash-vaporizes the liquid. This expansion pushes it out of the nozzle. The fog exiting the machine is very hot, and will rise up.

This device cools the air in which the fog is suspended, therefore causing it to sink to the ground.

Design
I designed this chiller myself, and I think the design is unique.

Fog enters the device at the top. At the top, there is a large expansion chamber, so that the fog can properly mix with the air.

Below this expansion area, there is ice. This cools the fog. Once the fog is cool, it will sink down below the ice into another chamber.

On one end of this chamber, there is a fan to blow the fog. On the other end, there is a hole for the fog to exit. This further mixes the fog with the air, and blows it out.

The theory is that the fog will expand in the first chamber, as well as cool. Once the hot fog has cooled enough to sink below normal air, it drops below the ice and is blown out.

If the amount of incoming fog is too fast for the cooling, then the fog will not cool as much, but will still be forced through the layer of ice, most likely resulting in enough cooling to retain the effect.

The whole device is fairly small, only about twice the size of a fog machine, and can be built with easily obtainable materials for not much money.

Comments

[lockpick]

You could use this to make a fog screen display. I am currently working on one. Great bile'

[brandon83]

just finished making this but my new 9V battery gets weak after a few minutes. is there another battery i can use with better results? my fan is 12V, it says.

do i need a few batteries in series?

thanks

[mman1506]

use AA batteries, D or C these batteries will last much longer as the have many more milliamp hours (MAh) than a 9v

[kef4444]

where did ya ghet your smoke machine from?

[T3Hprogrammer]

I think I got it from walmart. You can find them everywhere about this time of year (Halloween)

[sirlol]

I'm not sure if I put enough ice in, but I realized room temperatureaffects it a LOT. Essentially, the cold fog will sing through warm air,so keeping the room warm will do it.

I'll try more ice and a low circulating fan.

[jakeryan9]

v Me too! I have the same one. Only that it cost 40 bucks, but I got it for 20.

[XOIIO]

I have the exact same machine! I am so going to make this. im just wondering, could you have the fan where the fog exits, or will it dissapate too much?

[T3Hprogrammer]

I don't anticipate it being a problem. Try it!

[DJ_JS9]

well i am a dj and i have a 200$ DMX and all that industrial party strenth fogger and i was wondering if this would work for that too mine shoots about 20 feet and it about 3 times bigger than his

[chi chi chippy]

hey all u out there i was wondering if there is a way to make a fog machine. not a chiller but the machine. if u can help tell me

[neardood]

I wouldnt use a 9v battery with a 12v fan. You'l wear out the battery real quick and the fanwill under-perform. Try useing a proper 12V supply or battery

[frollard]

I wouldnt worry about under-voltage on a cpu fan that much; they are pretty tolerant, and simply (as you say) lose speed. If you underpower it too much, it will just stop. I built the other one - super cheap version, and I love the results. I imagine this has a very similar effect, but a constant flow - the fanless one 'billows' more.

[neardood]

you're battery is gonna die in about half aan hour if you left it on

[munchman]

You could replace the 9v with a variable power supply

[neardood]

good idea though, i'd make one of them if I had a fog machine

[wupme]

I really this idea. I think i'm gonna cool it with a PC watercooling system. Just that i'm gonna use the radiator to cool the air. Then for CPU cooler i'm gonna add a thermoelectric cooler to it, with an "aircooler" for CPUs on the other side. I think that could get cold enough. Well if not, i still can use it to chill a PC :)

[davidprosser]

I like this, but the problem is that this unit would be in the wings of my stage, and with the lighting and actors, it gets very warm in this area. So blowing warm air into a box of ice is not the best thing for me. Would it be possible to have the fan fixed internaly and blowing out through a hole? Then no unnecesary warm air would melt the ice.

[T3Hprogrammer]

You could probably mount the fan inside the box (or, as others have suggested, the exit hole) and eliminate the warm air intake. But if you want to put it inside the box, be sure to use dry ice so there is no water that could short out the fan.

[davidprosser]

or could i put a piece of plastic or something like a hood on the fan, and have a small hole below the smoke outlet for water drainage

[T3Hprogrammer]

sure, nothing wrong with that

[gilbert2048]

if you have a drainage hole you wont have to worry about the water.

[Father Christmas]

well, i had the same fog machine as you do. i also have one from the same company, with an ice chamber built in, made specifically for ground level fog. i like your way though, much more creative.

[MasterMediaXD]

Make this and attach it to your fog machine with the ready ice chamber for extra low fog!!!

[MasterMediaXD]

It might make frost not smoke! lol

[Father Christmas]

hahaha yeah

[MasterMediaXD]

It might make frost not smoke! lol

[MasterMediaXD]

maybe snow! lol

[Gooberz]

I'm reminded of a basic "Swamp cooler" design. Cool, good job.

[duct tape]

You should use dry ice in the cooler to give extra fog off.

[T3Hprogrammer]

Yes, dry ice works great in fog chillers, and there's no water to drain away.

[lordhazzard]

i was thinking, instead of ice maye you could use some form of liquid cooling, like a fridge, with cold water being,. say, pumped out of bucket (with a electric pump) with water and ice, and into the chiller with all the pipes arranged for lots of surface area, then you could refill the water quickly. but i worried about the noise, im a filmmaker and i need a quiet mist/fog machine

[N!$#]

This is how the commercial fog chillers work. If you're going for silence, look into using a liquid cooling system for a PC. They will be quieter than a large cooling unit. I can't say how effective the liquid cooling unit may be since it is intended for cooling by conduction instead of convection.

[jhdesynz]

Liquid cooling was an excellent thought, but doesn't chill, just cools to room temperature. For the fog to stay low, it has to be below air temp.

[jhdesynz]

Hey guys, I work in the theatrical industry and have a few praises and a few suggestions. Excellent job breaking it down. this is basically how a pro-grade unit works. -Dry Ice (frozen CO2) is a must to get a good heavy fog. Its cheap and as long as you wear safety gear, easy to work with. Plus you won't have any water to worry about. You can buy it at some grocery stores, an oxygen supplier or some party stores will have it. -If you run a drier hose between the fogger and the chiller, you won't have to worry about the height. - If you are using dry ice, it will be more effective if you build an interior compartment with a 3in pipe (drain spout pipe with all the holes works best) and lower it to the bottom of the chiller. Then place the fan at the exit instead of the entrance. The fogger's "blast" will push the fog into the chiller fine and the fan will pull the chilled fog out nicely. This will only work with dry ice though as the water will short out the fan otherwise. One other thing, if you use the dry ice, put a blanket on top if you don't fill it to the lid. that will keep as much oxygen away from the dry ice as possible and it won't evaporate as quickly. Good job with a nice, inexpensive chiller!

[macwhiz]

I have the same fogger. i got mine at Michael's and it is so awesome i added a timer controller.

[T3Hprogrammer]

I know there is already a fog chiller on Instructables, but this one is a different design. His is cheaper and easier to build, but I will claim that mine works better. I suggest you look at both and decide which one is best for you.

Super-Cheap-and-Easy-Fog-Chiller

[admanrocks]

ya, I like yours too! Good job!

[Spectrace]

thats neat, good instructable. Its nice how everyone takes a different view on the same thing. If i did this, i would have used dry ice instead of ice ice dry ice i think lasts longer, and its alot colder. And one question, where did you get the 13 dollar fog machine, because im looking for a fog machine, not only for halloween. and i only have like 20 bucks for a buget.

[T3Hprogrammer]

it was either at the grocery store, or walmart. walmart is more likely to have one.