Mini Dry-Ice Fog Machine





Introduction: Mini Dry-Ice Fog Machine

About: I'm Mike, from The Geek Pub. I'm a maker. I love to make things. from woodworking to electronics. Follow along with me!

Are you about to have a party? Need to setup some props for Halloween? About to put on a play at the local school or church? Then you my friend need a Dry-Ice powered Mini Fog Machine!

And I'm going to show you how to make one for less than $10.

Step 1: Watch the Video!

Even though this is a simple project, it's really helpful to watch our video. So take a second to do that, and then head on over to Step 2!

Step 2: Items Needed

You're going to to need to following items to complete your Mini-Fog Machine. You can get them all at your local big box store.

  • Small plastic container
  • 2.5" PVC Adapter
  • 2.5" PVC Pipe, 6" long
  • Computer Fan
  • 9V Battery Snap
  • 9V Battery

Note on sizes: You can make your Mini-Fog machine bigger by buying bigger components. A trash can and a box fan would make a huge fog machine for example. All you'd need then is more dry ice and more water.

Step 3: Cut Out the Holes

You'll need to cut two holes in the mini-fog machine's plastic container.

Cut the first hole in the top (the lid). Make it slightly smaller than the computer fan you purchased. Cut the second hole in the side of the plastic container. This hole will be where we thread the PVC fitting into. Make this hole smaller than the threads so that they will screw into the hole and seal it when done. Just 1/32" to 1/16" smaller should be plenty.

I used masking tape to cover the lid and sides of my mini fog machine. This allowed me to mark on the tape and then remove it when done, leaving no markings on the finished product.

You can cut the holes with anything from a razor knife or sharp scissors to a rotary tool or hole saw. I chose the rotary tool with hole cutting attachment, because I already had one.

Step 4: Attach the Fan and Outlet Pipe

Use hot glue, or CA glue ("super" glue) to glue the fan to the lid. CA glue won't hold up to moisture rich environments as long a hot glue, but it should do the job. If you bought a square computer fan, you can just use some screws and the four screw holes provided.

Screw the outlet pipe into the hole you created earlier on the side of the container. No glue is needed, but you could use some hot glue if you desire.

Once that's complete, attach the 9V battery to the 9V battery snap and twist the wires together from the snap to the fan. Red to red, black to black. If there are four wires on your fan, only use the red and black. The other two are speed controllers and not needed for this project.

Step 5: Boil a Few Cups of Water

Boil a few cups of water in the microwave. Generally 3 minutes or so.

Step 6: Add the Water and Some Dry-Ice

Pour the boiling water into the Mini-Fog Machine's container. Be very careful not to spill it as it will of course burn you badly.

Carefully, using gloves, break of some dry-ice and gently place it into the boiling water. Do NOT drop it in the water as it will splash boiling water out!

Place the lid back onto the container with the fan running,

Step 7: Enjoy the Fog!

That's it! You're mini fog machine should be making a ton of fog! Place it on the stage or behind your Halloween decorations and let the fog cover the area!

If you liked this project, you'll probably like my other projects too! So be sure to check me out here on Instructables, on my website at The Geek Pub, and over on YouTube at



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    30 Discussions

    I'll probably make it, and add some improvements, like an automated dry ice dispenser.

    I saw a video when you put small pieces of dry ice (about 1 lb / half kilo) in a bucket of very hot/boiling water.

    Instantly, your floor disappeared underneath the fog about a foot high (and probably higher in enclosed spaces.

    Hi, can you tell me how long the fog effect lasted before the water cooled to much to make a decent cloud?


    2 years ago

    Not sure what big box you are referring to, but I cannot find the fan or 9-volt battery snap at any big box retailer.

    3 replies

    You can get them both at Fry's or Best Buy.

    How were you able to complete the entire project for $10.00? The cheapest fan at best buy I can find is $15.00. And the only fans they carry are 12v, not 9v. Running a 12v fan on a 9v battery will burn up the battery in minutes will it not?

    I got my fan for less than $5. All computer fans run at 12v. That's not how this works at all. A 12v fan running on a 9v battery will run just fine. It will run at 75% of its rated speed, but other than that function 100% normally. In other words a 2000 RPM fan will run at 1500 RPM, which is more than enough for this project. In fact, some people have modified my project with a potentiometer to slow the fan down even more.

    I am so excited by this idea! Thanks so much for creating this tutorial! Do you have any suggestions on how one could make a portable or wearable version of this device? I will be part of a creative fashion show in a couple months and the theme is "7x7" in reference to the show's 7 year anniversary and San Francisco, where it originated. My vision for my outfit includes a tribute to "Carl the Fog" (yes, SF's fog is named Carl --- and even has a Twitter account). I'd love to be able to make a tiny, yet dramatically powerful version to conceal under my dress so as I walk it looks like I'm floating on clouds, or something. Thanks again!

    Love the idea...but I'm not a "geek" so I have no clue how to power the PC fan with a battery. Can you enlighten me?

    2 replies

    Normal fans operate at 12V, so you can take a 9V battery and connect the red cable to the positive pole and the black to the negative, that's all

    Great! Thanks so much for your help...I'd like to try this for Halloween. We have an office decorating contest at my work and I'm hoping this will work better than the full-size fog machine I already have. It works too well for a small office space and the fog juice has a smell to it that might not be appreciated by my coworkers. THANKS AGAIN!

    OMG! Totally loved the project, but I`m really in love by your cutting machine! what's the name? I live in Brazil, and never saw one of those! I'm a student of architecture and I'm always using saw machines to do my 3D models! one of those would be AWESOME for me! hahaha

    3 replies

    Looks like a dremel tool with a router bit and a router attachment. You probably have if not dremel tools available, alternative "rotary tool" that will work.

    The router bit can be a little tricky to find though, because these tools are more often used for cut-off discs, polishing, and grinding. Using a router bit is less common and not as well known.

    Neat Ible. Since CO2 gas is heavier than air, you are likely also safe unless you lie down on the floor in a pool of in and start taking gaping breaths of it. Anyone standing above the fog will be breathing safely. One way people try to intensify the effect is by erecting floor level barriers to contain the CO2 gas, making the floor space actually fill with flooded gas. otherwise it spills to the lowest point and eventually blends with the air. I've often wondered if plants would benefit from a fog of CO2? If you have some potted houseplants, you could make an interesting scene by using the pots to hold the fog barriers up and the mist would flow around the leaves and make it look spooky, misty and foresty. Again, thanks for the simple ible!

    1 reply

    that is awesome!!! where does one obtain dry ice though?!