Halloween: Dry Ice Fog Machine




One Halloween, my family used dry ice for fog by dumping boiling water on it. I thought "I have an old PC fan... I wonder if I could use it for a fog machine that doesn't use water!" so I built it. I haven't been able to test it yet, so if anyone builds it, please comment how it turns out!
P.S. This is my first Instructable. Please comment!

Step 1: Gather the Materials

Here is what you need:

Paper towel tube
PC fan
9V battery
9V battery clip/holder
Super Bright Colored LED OR Super Bright White LED and colored plastic film (I didn't have any bright colored LEDs at the time)
Styrofoam cooler

Hot glue gun

Step 2: Cut the Holes

The first step is to cut the holes. Place the PC fan in the center of the lid and use the Sharpie to trace it. Then use the knife to cut it out. For the paper towel tube, trace it on the side of the cooler and cut it out. Last, trace the 9V battery next to the fan (not too close) and cut out a hole a little longer than the battery. For all of these holes CUT ALL THE WAY THROUGH.

Step 3: Glue the Fan and Paper Towel Tube Into Place

Now, if your fan has a yellow wire, cut it off (you don't need it). Glue the fan into the hole you cut in the last step with a generous amount of hot glue (to seal it), making it flush with the top of the lid. Cut the paper towel tube any length you want (I just made mine as long as the styrofoam is thick) and glue it into place. You may have to use bits of extra styrofoam to close up big cracks.

Step 4: Make the Bottom of the Battery Holder and Thread the Clip

Use the DUCT TAPE (VERY IMPORTANT) (you don't have to use white) to make a bottom for the hole you cut for the battery back in Step 2. Make sure it's really strong, then cut a slit at the top for the battery clip and thread it through.

Step 5: Prepare the LED (skip This If You Have a Colored LED)

If you don't have any bright colored LEDs on hand, use the colored plastic film and make a pile of 3 or more layers (the more layers there are, the darker the color). (OPTIONAL: Use plastic/Saran wrap to make the layers easier to handle.) Put the plastic film sandwich on the LED and secure it with hot glue (if you're a perfectionist like me, use the tip of the hot glue gun to shrink the plastic). Then attach a couple of wires to the leads. You can use heat-shrink tubing to keep the LED from shorting out. Make sure you have a way of knowing which is the positive lead! I had to start this part all over because I wired it wrong!

Step 6: Wire It Up!

The wiring is super simple, just connect the positive end of the LED to the positive wire on the battery clip. Then, connect the negative end of the LED to the positive wire of the fan. Last, connect the negative wire of the fan to the negative wire on the battery clip. In case you don't know (you probably do) the black wire is usually negative and the red wire is usually positive.

Your waterless fog machine is complete! Just add dry ice and have fun!

Fourth Prize in the
Halloween Contest

Participated in the
Duct Tape Tough Contest



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    10 Discussions


    7 years ago on Introduction

    Has anyone tried this without using water? I'm curious if it can pump out a decent amount of fog without adding hot water.

    Typically, I put 5 to 10 pound blocks in a basket and lower it into hot water (at about 130F).

    The main problem I have had with using dry ice is that once the water cools down, (which happens pretty quick), it fails to produce the smoke because it melts more slowly. I am going to attempt to construct one using a small inst hot water heater. Sometimes you can find them used for cheap.

    1 reply

    Oh yeah, I completely forgot about the water! I think I was planning to assume the air was warm, or to put a coil near the fan to heat the air.


    8 years ago on Introduction

    next year i am gonna make a few of these and put them on the back of my golf cart and drive around!

    1 reply

    Reply 8 years ago on Introduction

    Also, I agree with you about the tint. If you've ever seen the movie Cars, it looks a lot like the Ghost Light!