The stirring effect for the cauldron is created by the use of a staple of Halloween Props everywhere, a wiper motor. You can get them from all sorts of places, but we highly recommend Fright Props. For this project we want to keep the motor good and steady so we created a custom mount from some commonly available parts. Big box hardware stores carry metal plates that are meant for supporting deck posts. (Search for “Post Anchor”) We’ve found that with a couple of simple modifications they work great for mounting wiper motors securely inside props.
The first step is to enlarge the hole in the center of the bracket so that the wiper motor shaft and rubber gromet will fit. Once that hole is enlarged, mark the bracket for the three screw holes used to mount the wiper motor and drill the holes. A drill press comes in handy for all of this work, but a hand drill will also work.
Once the motor holes are drilled we added a couple of brackets to either side. These are again found in the framing / deck building areas of big box stores. They are typically zinc and are outdoor rated like the deck post bracket. This makes them good choices for props that will be exposed to weather. Before drilling and mounting the angle brackets make sure that there is enough clearance for the brackets to reach the mounting surface when the motor is in place inside the post bracket. When building these mounts we typically use pop rivets to mount the corner brackets to the post bracket, but bolts work too. If you do use a bolt, make sure to use lock nuts as there will be vibration from the motor, and no-one wants to be digging around inside a prop on Halloween night trying to re-attach a nut that came undone.
This is a good time to attach the wiring to the motor if your motor doesn’t have the wires permanently attached. ( Use the 12V, and Slow terminals )
Now that we have our mounting bracket completed we can mount the wiper motor using the provided mounting hardware. Note the use of the lock washers. These help to keep the bolts tight on the motor frame. If you are worried they might work loose over time a drop of thread lock compound on the bolts should ease that fear. We’ve never needed it though as long as the bolts are tightened down tight. Also, don’t put the thread lock on until you are absolutely certain everything is ready for final assembly. You will likely need to remove the motor a few times while construction is under way.
Once the motor bracket is complete, we had to center it in the cauldron. The cauldron we are using is a large cauldron we picked up from AtHome at the end of the season last year for $20. Its important that the shaft of the motor is as close to the center of the cauldron as possible. This is where it might make sense to remove the motor from the bracket again so you can more easily line up the center hole with the center of the bottom of cauldron. (Hindsight is useful…) Once you are certain the shaft is aligned to the center of the cauldron, mark and drill your holes. We also drilled a hole in the bottom to run the motor and LED lighting wires. We later came back and added holes for water drainage, and a hole for the fog tubing.
