Mixing water with electricity is typically discouraged, and for good reason, but in this
project we're pumping electricity into water, and a bit of drain cleaner to create a poor
mans power controller. You might have heard of a Variac. This is the Scariac.
In a couple of other projects, we fashioned a homemade stick welder using parts we salvaged
from old appliances. I powered the device with 240 VAC, and that was plenty of power,
but we still needed a way to adjust the current. I built this device to control alternating
current, so we have the ability to play with adjustable power settings, on a budget.
Now this concept is about as dangerous as sticking two live wires in a bucket of water,
it can be deadly, so it's important to know, and understand the risks. To build this Scariac
we'll need a 4 gallon container to hold our electrolyte, and I like this one because it's
got a lid that snaps on tight. I cut a piece of board so that it measures at 16"x14" because
that fits on top, leaving a 3" overhang on the side. I made this plastic template for
marking holes for where the switch and outlet will go, and a few other markings based on
these measurements. To cut the holes out, let's drill the corners first, then use a
jigsaw to cut the sides. We can use the light switch as a template for marking where the
two holes will need to be drilled. This part is optional, but let's go ahead and finish
the edges with a 1/2" rounding bit on the router table. By profiling the tops and bottoms
of all the edges, we're left with a nice smooth finish. Next, we'll need 2 pieces of 2"x2",
and I had these ones left over, from when we made, our mousetrap hand guns, which you
can see in a different project. I drilled a hole through the sides of the blocks 1/2"
from the top, and cut them down to 1-1/4" so they looked like this. These blocks will
need to be secured flush with the top of the center hole, so let's trace the edges and
drill 4 pilot holes on diagonals. They'll eventually be held in place with screws from
the bottom side. I gave these parts a paint job, and now the panel board is complete,
and we can move on to constructing the power lever. All the parts for the power lever are
laid out here, and you can see they're mainly 1/2" PVC parts, as well as these other miscellaneous
bits of hardware. Now we can get to work priming and cementing the PVC together so that we
end up with 2 sections that look like this. They'll be fit together later on, but here
you can get a basic idea of how it's gonna work. We'll need to mark, and drill a hole
right through the lower part of the "T", then make the hole bigger on the inner sides. The
hole has to be just big enough to allow the head of a 2-1/2" bolt to pass through. Here
you can see I added a metal washer, and a beveled rubber washer on the inside. At this
point, the 2 parts of the handle can be cemented together, and the excess glue wiped away.
I decided to paint the handle red to give it a nice contrast against the black.
We can add a rubber washer
to the bolt first, and the block gets pushed on next, until you see about 1/4" of the bolt
poking out on the end. I added a washer and a wing-nut to hold it in place, and now we
have the ability to adjust the tension of the power lever. Now that our blocks are attached,
let's push the bottom part of the handle through the hole, and secure the blocks to the board
using the screws we lined up earlier. At this point, we're ready to wire up the electrical,
and this is how it's going to look when it's finished. I started with two 17" pieces of
1/2" copper tubing. Let's make 4 markings at 3, 4-1/2, 12-1/2, and 14". That should
leave us with an 8" gap between the middle markings. Now we can use a hammer or bench
vise to compress the copper, allowing us to bend it over easily. When all the markings
have been compressed, including the tips, the electrode can be formed into a rectangle,
and should look like this. I've drilled a hole through the center of the tips, continuing
into the tube itself, but only through one side of it. For this electrode, let's add
a 4" plastic PVC riser, so that it lines up flush with one of the edges. Then we can put
a screw right through it, so it's held between the two pieces of copper. The other end of
this riser can screw into the bottom of our power lever, making sure the copper bar is
facing forward. The other 4" riser gets added into the power lever, and can be secured to
the copper as well. To form the 2nd electrode holder, I added a PVC cap to a 6" PVC riser,
and used a belt sander, to grind away at the top until it was completely flat. With the
power lever in the full upright position, we can get a feel for where the longer risers
will need to be attached. Using 2 screws for each riser, we can bite down into the riser
caps, securing them in position. Now the second electrode can be added, adjusting it so it's
the same height as the first , and of course 2 more screws will fix the copper in place.
Now it's time to rig up the wiring for this contraption. I've got some 12 gauge cable,
and a 2 prong plug. The plug opens up allowing us to connect our 2 wires, and screws back
together, completing this end of the cable. The black wire from the cable runs to the
light switch first, and connects to the screw on the far side. The wire is cut, and connected
to the other screw on the switch, then continues to this hole drilled through the board. On
the top side, you can see the wire is bent over in an arch, and goes back through the
board, where it continues to the electrode on the power lever. The electrode wire can
simply be connected by looping it behind the existing screw and fastening tight.
Let's use another piece of the black wire and connect it to the other electrode in the same way.
You can see this wire connects to the outlet, and gets held on with one of the gold screws.
This silver screw is connected to the white wire running from the cable, and this completes
our electrical work. At this point we can fasten the light switch and the outlet onto
the control board, and add the faceplates for a finishing touch. This control panel
is fully functional, but if you wanted to add a little more safety, you
could add a replaceable fuse, or even wire up a circuit breaker. To finish up the system
we'll just need to modify this lid. We can use a rotary tool with a cutting wheel to
cut along the inner edges leaving just the rim intact. The inside hole has to be large
enough to allow both electrodes to fit in freely, and when it's centered on the top,
we can screw together the 4 corners, so it's all attached. This way, it clamps into position
perfectly every time. I wanted to add a piece of trim around the power lever, so I stopped
at the grocery store and picked up a container of bean dip. The empty container is exactly
the right size, and with just a little cutting, and two pieces of double sided sticky tape,
it mounts right behind the power lever. Our last step is to mix the electrolyte. I'm using
about 2 gallons of tap water, and that fills the container up half way. To make the water
more conductive, we'll be using this crystal drain cleaner because it's 100% lye.
This stuff is so dangerous and so potent, that we'll only need 1/4 teaspoon mixed into the entire solution.
Now we can secure the control board in place, connect the plug to a power source, and test
it out. Let's make sure the power lever is pushed fully forward, before the switch is
turned on. Now the system is powered, and you can see that if we gently pull the lever
back, the light begins to glow dimly. And if we pull it all the way back, it increases
to full intensity. The switch is a kill switch and will cut all the power to the system in
an instant. The main purpose of this contraption, is to regulate current to our electrical devices.
Adding just a little power to an angle grinder will cause the device to spin very slowly.
But pulling back on the lever will increase the power until it reaches full speed.
The control panel has this loop of black wire, that allows us to monitor the amperage, in
high power applications, like the arc welding project. You can see that if we pull back
on the lever, the current climbs higher. An interesting observation is that the voltage
is pretty much constant through the entire cycle. The system can handle extremely high
electrical loads, and in contrast, it can also make a table saw turn at a snails pace.
Pushing forward on the lever increases the electrolytic resistance, and as a result,
the equipment slows down, or comes to a full stop. Well now you know, how to control electricity
with water and a bit of drain cleaner. Remember, that this has the power to kill you, and that's
why it's called the Scariac. If you liked this project, perhaps you'll like some of
my others. Check them out at www.thekingofrandom.com