Halloween DIY: Glow in the dark smoking cauldron ⋆ Welcome to the Necro Nomnomnomicon

The weather is getting cooler and that means it’s bonfire season! I love nothing more than cozying up to a bubbling cauldron atop a roaring fire on a chilly autumn night. Mmm, heaping bowls of piping hot sinner stew warms my belly and my soul. Granted, what’s in my cauldron probably won’t be in your cauldron, but it doesn’t mean you can’t make one that looks like mine (just without the actual body parts and pesky lines of questioning that might arise from the local authorities regarding missing hobos!)

This DIY is not only relatively easy, it’s surprisingly cheap for the level of effect you’ll get from it. My entire build, from start to finish, came in around $100, including the fogger.

To make your own smoking cauldron, you will need:

1 large plastic cauldron (I got an 18-inch diameter one)
1 can of Great Stuff expanding foam
1 bag of plastic bones
1 can fluorescent green spray paint
1 can black spray paint (glossy, satin or matte, doesn’t matter)
1 can glow in the dark spray paint
1 flexible 4″ dryer hose
1 tube E6000 glue
1 black plastic platter (mine was 16 inches in diameter)
8 neodymium magnets (optional)
2 binder clips
Roll of duct tape (silver or black)
1 4″ to 2″ PVC Flexible Couplings (get the kind that comes with worm screw pipe clamps)
1 2″ ABS threaded male adaptor
Plastic grocery bags
Painters tape
Fog/Smoke machine
Fog juice
Bags of ice (either regular or dry)
long thin dowel/pencil/screwdriver – something at least 6″ long and thin
Drill or Dremel

(You should be able to get all the hardware supplies including the magnets, paint, tape and PVC couplings at the hardware store)

I used super strong rare earth magnets to help secure the platter to the lip of my cauldron. While this step is optional (the weight of the foam and bones on top will help keep it in place if you decide to skip the magnet step) I like how it keeps the edges down and prevents the lid from sliding.

I spaced the four magnets around the edge of my cauldron on the underside of the lip and then used the E6000 glue to secure them in place.

I put the corresponding magnets on TOP of the lip of the cauldron to help hold the magnets on the underside while the glue was drying. Once dry, when you remove the top magnets, the magnets on the underside will stay in place.

Set your platter on top of your cauldron and line up your magnets along the edge, making sure they match up with the magnets you glued to the underside of the lip on your cauldron. Glue the magnets to the top of your platter, again using the E6000 glue. Allow to dry fully.

On the backside of your cauldron at about the halfway point, cut a hole large enough to fit your 2″ ABS threaded male adaptor and glue into place using your E6000 glue again. (I also wrapped a few strips of duct tape around it to help secure it in place and make sure it was air tight)

Attach the PVC flexible coupling to your dryer hose using the included worm screw pipe clamp.

Now that those steps are done, let’s move onto the fun steps! Decorate your platter with your expansion foam. I did two layers, using the first to give a good base and then piling up the second layer for more depth. As your layers start to firm up, embed in your bones.

Once you are happy with the placement of your bones and your foam is fully dry, it’s time to start painting.

Using your plastic grocery bags and painters tape, mask off your bones and anything you don’t want to be painted green and black.

Lay down a base of black spray paint and then go over with your flourescent green. Add in layers of green and black as you want to help add depth.

Once your paint is dry, peel off your tape and bags and reveal how awesome your platter looks already!

Highlight your cauldron topper using your glow in the dark paint, allowing it to dry between layers. Because it dries anywhere from a clear to a slightly powdery white, I sprayed my entire piece with it. Thin layers dry clear, heavier applications dry white. I used a thin layer over the green and black parts and a thicker layer over my bones. In the light fully assembled, it looks like this:

…and in the dark, you get this:

At this point, you could simply stop the project and call it good, but we’re adding FOG!

Flip your platter/cauldron topper over and carefully drill holes into the bottom. Using your dowel/pencil/screwdriver (whatever) push through the foam all the way through. You want to create holes to allow your fog to escape the cauldron. I punched about 10 holes into mine.

Use your spray paint to touch up any spots on your topper where the foam flakes away.

Attach the dryer hose to your cauldron using the two couplers.

At the other end of your dryer hose, use your duct tape to tape down the edge of the hose. This makes it a little more rugged as the hose itself is fairly thin and the material tends to tear.

You also want to make two tabs that extend off your hose by about two inches. Do this by doubling your tape back on itself and then taping to the end of your hose. You’ll clip these to the nozzle of your fog machine with your two binder clips.

(The devil is in the details: When attaching your hose to your fog machine, make sure you leave a gap of at least an inch between your hose and your fog machine nozzle. The machine needs the air to mix with the fog to create truly thick billowing clouds. If you seal it too tightly, the fog will remain liquid and you’ll end up with no fog in your cauldron and a puddle of wasted fog juice under your machine.)

Fill your cauldron with either bagged ice, or for a truly ground clinging effect, dry ice.