Fog Chiller & Tombstone Prop

Soon after my son joined the Cub Scouts last year we were invited to the annual Pack 602 Halloween party. Being a part-time mobile DJ I offered up my services. Being a full-time tinkerer, I wanted something to stop the pack of boys in their tracks and make them say wow!

I decided to create a tombstone & fog chiller for my fogger. The typical fog machine puts out a fairly hot stream of fog which floats up and away, dissipating quickly. Running the fog through a "Chiller" causes the fog to hug the ground a lot longer, giving you a low lying "graveyard fog".

 

The Chiller is a container that holds ice as the fog passes through it, thus cooling the fog. If you were paying attention in science class you'll remember that hot air rises and cold air falls.

 

You can buy fog chillers on-line or at stores from $200 on up to over $500. I decided to build one for less than $20 in parts.

 

 It was a huge success! Follow along as I walk you through my first (but not last) Halloween craft build.

****Don't forget to vote for my project!****

Unfortunately, I built this before I discovered instructables.com so there is a distinct lack of detail pictures. I’ll do my best to recreate the details here.

Supplies:

Qty.                  Size                 Material

1                      15”x36”            particle board (tombstone)

1                      15”x6”              particle board (box face)

2                      6”x10”x2”         particle board (side pieces for box)

1                      15”x10.5”         particle board (bottom of box)

1                      14”x2.5”           particle board (cross bar inside of box)

1                      4” od                PVC plumbing flange

3                      4”                     wooden letters

1                                              black spray paint

1                                              grey spray paint

1                                              Velspar Stone paint

1                      3”                     PVC pipe

2                      3”                     PVC elbows

1                      25 gal.              storage bin

1                      12’                   dryer hose

4                      3”                     L brackets

1                      12”                   piano hinge

I started off with 15" wide particle board. Not the ideal wood for an outdoor prop I know, but it was plentiful and already cut to 15" wide. I then cut it 36" high. I used the old pencil with a string trick to get the desired radius for the top of the Tombstone. I then cut it with a jigsaw.

I then cut a narrow slit at the bottom of the tombstone, more on that later...

I built a slanted box to attach to the back of the tombstone. The You'll notice in later pictures that I also cut a 3" hole in the back of the box and mounted a 4" o.d. plumbing flange to connect to the chiller. I then crafted a lid out of aluminum diamond plate and added the latch to keep the lid closed tight.

 

The latch is sometimes called a “Tool Box Draw Catch”. I had to modify the way that I installed it though. Instead of drawing the “bolt” into the “catch”, I positioned it so that the “Loop” caught the “bolt” securely. . I also added bulb seal to the bottom of the lid to give it an air tight seal.

 

 

I used black and grey spray paint to add shading and detail before the final finish. Then painted the whole project in Valspar Stone paint.

Once the paint dried I stapled and glued the letters to the tombstone. My step-daughter who was in theater all throughout school added more detail to age the stone.

For the next series of steps I took over my wife's kitchen! I used a large storage tub we had lying around and cut a 3" hole towards the top of one side and the bottom of the other. I cut 3" PVC pipe 3" long and used silicone and L brackets to secure them in place.  You'll notice that I reinforced the areas with pieces of plywood to stiffen up the sidewalls where the pipes would be inserted.

I then installed the dryer hose to both ends of the tub. I had to use hose clamps to tighten the 4" hose onto the 3" PVC. (They didn't have 3" dryer hose.) I cut a few slits in the hose to make it fit tighter. To chill the fog I simply fill the tub with ice, making sure to get it down in between the hose and spread out evenly for maximum cold air coverage. Then as the fog passes through the tubing it gets cooled down drastically.

I then cobbled together several pieces of PVC to create the intake for the fog machine. I didn't glue the pieces together so that they could be taken apart for storage. I also used a short piece of dryer hose to connect to the tombstone. It's important to leave a gap of an inch or two between the fogger nozzle and the intake tube, creating a vacuum of fresh air for the fog stream to mix with allowing it to expand.

I painted the inside of the box white to make it as reflective as possible. I then Velcroed battery operated remote control lights into the box to give an eerie glow as the fog exits.

The end result was a great looking Tombstone prop that also dispensed a ground hugging fog. I didn't get a good picture of the chiller without the blue light, but I think you get the idea.