Yard Plotted to scale, promise

make it yourself

Ground Fog Chiller

A cooler, a bag of ice and a length of dryer duct that turns a fog machine's rising white cloud into fog that lies on the grass and rolls. Two hours to build, and it is the difference between fog working and fog being a waste of an evening.

  • $68 ish
  • 2 hrs start to finish
  • total beginner
  • 1' 4" tall when done

grab this stuff

What you need

  • Fog machine, 400 W or larger $40
  • Fog fluid, 1 liter $10
  • Hard cooler, around 25 quart $12
  • Flexible dryer duct, 4 in. x 8 ft $6
  • Bag of ice, on the night you have these
  • All in $68

Tools, and that is it

  • A drill with a hole saw, or a craft knife and patience
  • Duct tape
  • An outdoor extension lead and an GFCI adapter

here we go

How to make it

  1. Cut two holes in the cooler

    One hole in the short end near the top, sized to your fog machine's nozzle. One hole in the opposite end near the BOTTOM, sized to the dryer duct. Fog goes in high and warm, falls as it cools, and leaves low and cold.

    oops-proofing

    Get the heights the right way round. In low and out high is a chiller that does nothing at all, and it is an easy mistake because it looks tidier.

  2. Keep the machine outside the box

    The nozzle pokes into the hole; the machine itself sits on the ground outside, on a paving slab or a board rather than on wet grass. Tape round the nozzle to seal the gap so fog does not blow back at you.

    oops-proofing

    Never put the machine inside the cooler. It runs at a few hundred degrees at the heater block, it needs air, and a sealed insulated box around a heating element is how you melt a cooler and ruin a machine in one go.

  3. Ice, not water

    Fill the box with bagged ice or frozen bottles and leave a clear channel through the middle for the fog to travel along. Melting ice is what does the cooling, so a couple of bags will run you an evening.

    oops-proofing

    Do not tip loose ice in until it is a solid wall, and do not fill it with cold water. Fog has to be able to get from one end to the other; block the channel and the machine just pressurises the box and puffs it back out of the inlet.

  4. Run the duct low, and aim it downhill

    Lay the dryer duct out along the ground, hidden in planting or under leaf litter, and let it open somewhere the ground falls away. Fog is heavier than air and will run downhill on its own, so on a sloped lot you can put the box at the top and let gravity spread it across the whole yard for free.

  5. Bursts, not continuous

    Thirty seconds on and two or three minutes off is plenty, and most machines have a remote with a timer. A layer of fog sits for several minutes once it is down; you are topping it up, not manufacturing it continuously.

    oops-proofing

    On continuous a 400 W machine gets through a liter of fluid in about an hour and then everything is a white wall with no shapes in it. Fog is a floor, not a fill. If you cannot see the props any more, there is too much.

  6. Light it from the side, low down

    Put a spotlight at ground level off to one side, aimed across the fog rather than into it. Colored light works better on fog than white does, and this is the one place in a Cryptid Crossing yard where the amber spotlights earn their keep twice.

    oops-proofing

    Front lighting is the other classic fog mistake. A light behind you aimed at the fog turns it into a flat white sheet and hides everything standing in it. Side and back light give you the beams and the depth.

one more thing

CHECK THE FORECAST. Anything above about five miles an hour of wind takes ground fog off your lot entirely, and no amount of chilling fixes that. This is a still-night effect, which on most streets means it works on perhaps half the evenings you want it. Keep it well away from the front door. Fog drifts indoors on the draft every time somebody opens up, and glycol fog sets off optical smoke alarms reliably. Fog fluid is slippery on paving and on steps, so run the duct out onto grass or a border rather than across the walk people are about to use in the dark. Machine and lead both want an GFCI adapter, the same as everything else outdoors, and the machine wants to be off the wet ground on a slab.

where it goes

Layouts this one lives in

Same build, any yard shape. Here is where it lands.

  • → The Old Cemetery on a Wide Shallow, No Porch Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Narrow Shallow with Porch Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a L-Shaped with Projecting Garage Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Deep Narrow Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Corner Lot Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Split-Level or Raised Ranch Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Sloped or Terraced Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Small Urban Postage Stamp Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Circular Driveway Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.
  • → The Old Cemetery on a Long Driveway, Rural Frontage Leaning stones, an iron fence with a gap in it, and candles along a path that nobody has swept in years. The one Halloween theme with nothing alive in it, which is what makes people slow down instead of laugh.