DIY Fog Chiller
A fog chiller cools the hot output from a standard fog machine so the fog sinks to the ground instead of floating upward. The result is low-lying, ground-hugging fog that flows around tombstones and fills your graveyard scene with heavy mist. This is one of the best bang-for-your-buck builds in the entire haunt.
How It Works
Hot fog enters one end of an insulated container filled with ice. The fog passes over and through the ice, losing its heat. Cold fog exits the other end and, being denser than the surrounding air, stays close to the ground. Simple thermodynamics, dramatic results.
Materials
Parts List
- Large cooler (48-60 quart) — cheap Styrofoam works, hard-sided is better
- Dryer vent hose (aluminum flex, 4" diameter) for the internal path
- PVC pipe or dryer vent fittings for the inlet and outlet
- 20+ lbs of ice (regular ice, not dry ice)
- Aluminum foil to line the inside (optional but helps)
- Duct tape
Build Steps
- Cut a hole in one end of the cooler for the fog input (match the diameter of your fog machine output nozzle)
- Cut a hole in the other end for the fog output (4" diameter, near the bottom of the cooler)
- Run the dryer vent hose through the inside of the cooler from input to output, with slack so it droops through the ice. Alternatively, skip the hose and just let the fog flow through the cooler interior around the ice.
- Fill the cooler with ice around and over the hose
- Connect your fog machine output to the input hole
- Point the output hole toward your scene, near ground level
Tips for Best Results
- The more ice, the colder the fog, the better it stays low. Keep spare bags of ice ready for refills.
- Elevate the chiller slightly and angle the output downward — the cold fog should pour out and flow down to the ground.
- Don't run the fog machine on full blast. Moderate bursts give the ice time to cool the fog. Constant full-power output overwhelms the chiller.
- On warm nights, the fog will stay low for less time before warming and rising. Cooler October evenings are ideal.
- Drain meltwater from the cooler periodically through a plug or hole in the bottom.
Advanced option: For even colder fog, add rock salt to the ice (like making old-fashioned ice cream). This lowers the ice's melting point and makes the ice bath colder. The fog will hug the ground much longer.