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.

Step 2: Materials

Stuff you'll probably have to buy:

• Cheap Styrofoam Cooler: $3 at grocery store
• 1.5" PVC Coupling: Less than $1 at Home Depot
• Screen: $5 at Home Depot
• Computer fan: $2 at Goldmine, plus shipping

Stuff you probably have:

• Ice
• A fog machine
• 9v battery
• 9v battery clip (optional)
• String
• Tape

Tools

• A small flathead screw driver
• Pliers (locking ones recommended)
• Stapler (a normal one, spring-loaded Staplers ones won't work well because of the safety)

Step 3: How to Cut Holes in Styrofoam

This is not an actual step, but you will need to use it 3 times during this project.

1. Poke holes through the Styrofoam outlining area you want to cut
2. Loop a piece of string around the screwdriver
3. Push the screwdriver and string through the Styrofoam
4. Pull one end of the string from the inside until it is through the Styrofoam
5. Slowly pull the string back and forth, pushing it in the direction you want to cut
6. Move the string around the outline until you're back where you started. Poke out the piece you cut.

Step 4: Create the Screen

1. Unbend a coat hanger with pliers until it is straight. Cut off the ends if you can't straighten them.
2. Use a tape measure to measure the inside of the cooler. If yours is tapered, like mine is, measure it about half way down.
3. Bend the coat hanger into a rectangle matching your cooler's shape, using the dimensions you just measured.
4. Use pliers to wrap the coat hanger around itself to finish it off. Cut off any extra.
5. Gently push the coat hanger rectangle into the cooler. It should be able to slide about halfway. Don't push it in too hard, because you may break the cooler, or not be able to get it out. Once you're sure it will work, take it out.

Step 5: Create the Screen (cont.)

1. Measure and cut out a piece of screen about 1" bigger on all sides than the coat hanger rectangle
2. Fold the edges over the coat hanger
3. Pull the edges tight, and staple them
4. Put staples all around the edges, as close to the coat hanger as possible
5. You may need to manually bend the staples together
6. Trim off extra screen

Set it aside for later.

Step 6: Make the Lower Chamber

1. Refer to step two to cut a hole near the bottom of the cooler, on one of the short sides. It's a good idea to use the 1.5" PVC coupling as a guide.
2. Cut another hole of the same diameter directly opposite this one (on the other side of the cooler)
3. Place the fan over the hole, so that it blows into the box, and the wires are facing up. You may need to test it with the 9v battery. Poke holes through the Styrofoam where the mounting holes of the fan are.
4. Thread a long piece of string through one of the mounting holes, and into the cooler.
5. Finish mounting the fan by "sewing" it onto the cooler. Tie off the string when finished.
6. If you have a 9v battery clip, wire up the fan directly to the clip. A switch is optional, since it is easy enough to just disconnect the battery.

Step 7: Finish Up

1. Cut a hole above the fan, using the outside of the PVC coupling as a template. The top of the hole should be about 1" (2 cm) from the top of the cooler.
2. Insert the screen you made in step 3-4 into the cooler, pushing it down about half way
3. Push the PVC coupling into the hole. If it's not a good fit, seal it with tape. Make it flush with the inside of the cooler.
4. Poke some holes on the bottom front corners (near the hole with no fan). This will allow the melted ice water to drain.
5. Done! It should look like this.

Step 8: Using the Chiller

1. Fill the top of the cooler with ice, up to the bottom of the PVC coupling
2. Find something (a box, anything) to put the fog machine on. Place it so that the nozzle lines up with the PVC coupling.
3. Push the fog machine and fog chiller together until the PVC coupling completely covers the nozzle
3. Connect a 9v battery to the computer fan
4. Turn on the fog machine
5. Put the cover on the cooler, and weigh it down with something heavy (but don't break it!)

It is a good idea to paint the cooler black to be less conspicuous. If you plan on running it very often, you should also find a more permanent stand for the fog machine.

Step 9: Wrapping It Up

Notes for best preformance:

• Make sure no fog can leak out between the PVC coupling and the fog machine
• Make sure the cooler cover seals tightly
• Be sure to add ice every half hour or so
• Angle the whole setup slightly, so that the melted ice water can drain out the front of the machine.
• The only place fog should be coming out is the exit hole, opposite the fan. If it is leaking anywhere else, seal it.
• Wind kills fog. Running this on a breezy day will yield very poor results.

Here are some pictures of the fog chiller in action:
1. Through chiller, with ice
2. Normal Fog
3. Black Chiller

Comments

[VANCEALE001]

This machine does not work. I tried it with a 400 watt fogger and it did not work at all. I really like the idea and it's very unique and creative, but the problem is that the fog can't push through the screen fast enough. Only a small trickle of fog comes out, which is only a fraction of what the machine otherwise puts out. I even used a screen with large holes, and it still didn't work. Again, this seems like a good idea and a very innovative invention, but, as I originally suspected, the fog can't make it through the screen fast enough. Tell me if I'm missing something, though, because the picture looked like it worked fine.

[slegary]

Could you substitute regular ice for dry ice? I'm just thinking this way you could eliminate the melting of the ice...

[T3Hprogrammer]

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.

[Oncer]

Hi T3H, great 'ible! See my comment above about low foggers. The volume of gas produced from CO2 will push it out of the machine very quickly so there is no chance to refreeze plus you need a bit of pressure to freeze CO2 in normal conditions. See my comment about making blocks of dry ice from gas bottles. The box was fairly airtight and it was the pressure that caused the dry ice to freeze though I may be lying as I don't really know the physics but it did work - sort of as I said. I'm pretty sure the pea soupers we used with dry ice didn't use fans though it's been a long time since I've seen them so again I may be wrong, though I do seem to have spent long sections of my life stood in the wings with big pieces of cardboard wafting smog, smoke and haze to where they where wanted by the director.

And yes CO2 will displace oxygen in small spaces so take care. And dry ice will also BURN you - well freeze of course but it will damage you. There was always some idiot who would drop in their drink for laughs and then go on to burn their lips.

[Oncer]

Or more nastily someone elses drink!

[Oncer]

And here's my £2.50's worth. In theatre we used to use dry ice for low fog/mist effects using commercial machines which were basically warm(ish) water baths into which a basket of dry ice was lowered thus releasing CO2 gas. This produced a dense low lying fog. The dry ice used to be delivered in blocks wrapped in paper but later on someone came up with a device to make your own dry ice from a canister of CO2 - basically a box into which the pressurised gas was blown. The gas would condense into a solid block, however it was incredibly noisy and longish process and used a huge amount of gas to get a block of ice less than a foot square of a crumbly texture ie. less dense than a commercially available block.

Later on we had low fog machines which used smoke machines and a refrigeration unit as T3H has here. A major draw back was these machines - in the 80's at least - where incredibly noisy. It was virtually impossible to use them without a loud piece of music to cover.

Now it all seems to be about haze. I haven't worked with a lighting designer in the last twenty years who didn't want copious amounts of haze. That's great for rock and or roll but for a drama piece it just makes the cast look like they're on 60 a day.

And a withered neuron has just fired! I remember my mother telling me about ice cream sellers in her youth putting a lump of dry ice - which they would have used to keep their wares frozen - into a metal bowl where it would jitter about as it sublimed and make the bowl ring. "Our ice cream is so good it rings a bell!"

[Jenntonic]

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]

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]

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]

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]

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]

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.

[tinker234]

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

[ohijoe]

If I may add my $5.00 worth of advice....

The way I used to change the color of the dry ice fog was with the
fountain lights that were/are 3 LED lights that would take turns
switching on and off illuminating the water as it flowed from the
fountain. It worked like a charm with the dry ice fog! But, be careful not to
add too much dry ice that you don't freeze up the fountain, For this reason, you might
want to put a screen around the fountain's bottom side so that water can
get in but the ice particles can't. I accidentally fried one of my wife's fountains up
that way. (4 years ago and I am still hearing about it every October 12th when we start setting up for Halloween on the dot!) But the effect was SO much worth the $15.00 (at any aquarium supply store) to replace it. at any aquarium supply store. However, you can get them cheaper now
especially at stores like Marc's when you purchase something that already has the
darn thing in it like their pumpkins! Hey! $5.00 for fountains is
nothing to sneeze at buddy! Buy the pumpkin and use it once a year but
the fountain all year for everything else!

Hope this helps you, if not maybe it will help another person. Sorry it was so late in reading your post, you could say I've been on quite a bedrest per doctor's orders.

[Jenntonic]

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.

[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

[lime3D]

Why? They are really cheap and ready to go. They have a tank, and pump, a heating element, and are self contained. Why reinvent the wheel?

[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