Instructables
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.
 
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Step 1: Design and Theory

Picture of Design and Theory
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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.
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tinker2342 years ago
wow awsome if and any way you could change the color of the fog als could i use dry ice for a longer time running than normal ice
Try using led lights, spot lights with removable color gels, black lights or pin lights with color gels up underneath the fog like Dj Lights that shine up at trees to show a colored fog effect. However, if you want to try something different, fun, with a short lived, yet awesome colored display of creeping fog, drop dry ice in a cauldron or glass of water with colored glow sticks and watch the awesome spectacle of fog bubbling and boiling over the top like a low lying fog of witches brew.
slegary1 year ago
Could you substitute regular ice for dry ice? I'm just thinking this way you could eliminate the melting of the ice...

If you have dry ice and enough of it, then you may not need a fog machine? I suppose you could substitute dry ice for regular ice, but I wouldn't recommend, since placing dry ice is tricky and might not work as well with this particular construction? But if you do have dry ice and prefer to use it as a fog effect, here's what I've seen: When you add dry ice to water, you get a similar type of fog effect, except its much more volatile and much more fun, when used safely and appropriately. (The First Rule to Remember, When Using Dry Ice is Handle With Care and Always Use Protective Wear. Since Dry Ice Is Actually the Solid Form of Carbon Dioxide, in This State Its Much Lower in Temperature than Frozen H2O, It Can Burn the Skin.) Depending on amount of dry ice, amount of water, temperature of water, and type of container used, determines how long, how fast, and how much liquid fog is produced. Lets say you have an 8oz glass of water at room temperature approximately one inch from the top and you drop one to two cubes or chunks of dry ice, what you get is an immediate chain reaction like a bubbling boiled effect which rushes a liquid fog over and down the glass.If you use a much larger or longer tub, container, or cauldron of water filled almost to the top, but not to deep, you'll need several bricks of dry ice to continue adding through the night, because it can go fast. As the dry ice or carbon dioxide is added to water, it changes to its gaseous state creating a bubbling boiling fog over the top and down along the ground effect. The hotter the water, the faster and quicker the effect. Also, you can drop colorful glow sticks as the dry ice is added and watch the amazing flare of colors look like they are boiling over. Some clubs safely use this effect on their specialty drinks with color, once evaporated. With enough Dry Ice you can create a low lying thicker fog, but may or may not produce as much, as fast a fog as a machine. To each is own. Some local grocery store chains carry dry ice, since its used for shipping cold items. t seems like you can never buy enough, sometimes, so plan wisely. It can be costly, too. Keep frozen until use, eventually it will dissipate into a safe gas, since a regular freezer is warmer than dry ice at 32 degrees.

I'm glad to see a smaller way to create a fog chiller and with the small fan, its genius! I'm gonna try it out. I'm a DJ who uses Fog and tons of lights every year at Halloween. Its a curse, I'm mean a calling to decorate my house and street during the holidays. Halloween and Christmas are a DJ's favorite time of year. Of course I'm the kind of girl who probably goes a little over the top, but at least I have fun.

Maybe, If you want to try different materials for your chiller, perhaps using a wider tube such as an aluminum dryer tube attached to the fog machine via aluminum tape, while running the tube through a fitted hole down or through the top of the lid of a larger bucket (painters bucket), tub, tote, or small 13 gallon garbage container through the interior and then out the side, instead and sealed with the aluminum tape. Add regular ice as needed. The pressure of the fog machine should be great enough to create a low flow of fog with out the extra fan, to create the same effect, though a fan may definitely help if the night is too still? If the tube is wider, made of metal or aluminum, with the right amount of regular ice, it should keep nice and chilled like a bartender's tumbler, as the fog machine blows the hot fog through the frosty aluminum tunnel it will instantly react and create a spectacle of low moving fog across a multitude of colored lights or gravely scenes.

Just saying….Sorry So Long….
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
T3Hprogrammer (author)  slegary1 year ago
This sounds completely reasonable. I see two potential complications:

1) The dry ice may be so cold that it re-condenses the vaporized gasses out of the air. I am not familiar with the exact physical explanation for fog, so this may not be a problem at all.

2) The cold CO2 generated by subliming dry ice will sink and displace the oxygen in a confined space. Don't put large amounts of dry ice in a confined space. The small amounts used here would not be a concern to me.

I recommend you try it out, it has the potential to work much better than regular ice.
lockpick3 years ago
You could use this to make a fog screen display. I am currently working on one. Great bile'
brandon834 years ago
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
use AA batteries, D or C these batteries will last much longer as the have many more milliamp hours (MAh) than a 9v
kef44443 years ago
where did ya ghet your smoke machine from?
T3Hprogrammer (author)  kef44443 years ago
I think I got it from walmart. You can find them everywhere about this time of year (Halloween)
sirlol4 years ago
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.
jakeryan94 years ago
v Me too! I have the same one. Only that it cost 40 bucks, but I got it for 20.
XOIIO5 years ago
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 (author)  XOIIO5 years ago
I don't anticipate it being a problem. Try it!
DJ_JS95 years ago
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
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
neardood6 years ago
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
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.
you're battery is gonna die in about half aan hour if you left it on
You could replace the 9v with a variable power supply
good idea though, i'd make one of them if I had a fog machine
wupme5 years ago
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 :)
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 (author)  davidprosser5 years ago
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.
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 (author)  davidprosser5 years ago
sure, nothing wrong with that
if you have a drainage hole you wont have to worry about the water.
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.
Make this and attach it to your fog machine with the ready ice chamber for extra low fog!!!
hahaha yeah
It might make frost not smoke! lol
maybe snow! lol
It might make frost not smoke! lol
Gooberz5 years ago
I'm reminded of a basic "Swamp cooler" design. Cool, good job.
duct tape5 years ago
You should use dry ice in the cooler to give extra fog off.
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