This is a fully functioning gumball machine and fish tank. The tank maintains healthy community fish and dispenses gumballs to anyone who comes through my living room with a quarter.
The project started when I was not able to find an old TV to turn into a fish tank, and honestly, it seemed a little too cliche. I still wanted something kitsch, colorful, and unique.
I'll try to keep my directions general because depending on the gumball machine model you start with, you made need to make modifications to these instructions.
Step 1: Find a Gumball Machine
Water is heavy, super heavy. I should actually say super dense. Assume about 9 lbs/ gallon. Gumballs are less dense than water, so you'll be asking the machine to hold more than its designed. Look for good fiberglass and acrylic machines with NO CRACKS. Avoid entirely plastic machines. Avoid machines where the globe is more than one piece, they will not work. The globe of my machine is very thin, maybe a little more than 1/8", but the spherical shape gives it more strength then you'd think. The fiberglass and acrylic stand supports about 100 lbs of water. It's been filled and unfilled move and dropped for a year, and I've had no problems. I found mine used online cheap from a local seller.
The outside condition shouldn't matter too much. You'll be painting it and tearing out the inners, but the structure and the mechanisms are important. If you want to have your machine dispense gumballs the internal machinery will need to work properly before you start to modify it.
Step 2: Take Everything Apart.
Take apart everything and clean it thoroughly. As you are taking apart the machine make special note to understand how the machine works. They are fairly simple, but you'll be assembling it and reassembling it multiple times throughout the process. By now, I think I can assemble a gumball machine with my eyes closed in under 30 seconds. I'm like a gumball machine navy seal.
SPECIAL NOTE: Many machines will use crazy screw heads to prevent meddling kids from taking them apart to get candy and quarters. I drilled those screws out and replaced them with standard bolts. Also, many will have locks, unless you're concerned that someone will steal your fish, get rid of those.
Step 3: Sand and Paint
Sand and paint the fiberglass portions of the machine to match your decor. I went with a classic red. I used a paint with "shimmer metallic" then high gloss spray overcoat. There are also some sprays that have glitter. This is an appropriate place for glitter, a controlled environment with a top coat to seal it in.
Step 4: Make the Globe Water Tight
To make the globe watertight you have to create a floor or a plug to keep the water from the coin mechanism. Water only fills up the top part of the globe. Find the diameter of your globe at what I call the "collar". That is, where the acrylic of the globe meets the fiberglass of the stand. It should be the diameter of the fiberglass minus the thickness of the globe. On mine there is a rubber bumper where the two meet. Everything below the collar cannot be seen.
You'll need to cut a circle of 1/4" acrylic to plug the globe. Measure the diameter of the collar, account for the thickness of the globe, and cut a perfect circle. Spend some time on this because it needs to be water tight.
Once you have that circle, cut it in half. You must cut it in half to fit it into the top opening of the globe (where you would have reloaded gumballs). Test the fit, make sure it is nearly water tight. Do NOT silicone the acrylic yet, more needs to be done one it, but just make sure it is a good fit.
Out of the same quarter inch acrylic cut a piece (shown in blue in the diagram) that will support the rejoining of the two half circles.
Step 5: Filter and Air Pump
This is the most difficult step. Your fish will need clean water and oxygen, so you'll need a filter and an air pump. These two machines will be hidden in the base of the gumball machine where coins would have been collected. The smallest canister filter I could find is a ZooMed 501 turtle filter (they can be used for fish too). It fit nicely next to an old aquarium air pump in the base of the machine. There is a little access door there as well that was once used to retrieve coins, but is now for checking in on the filter and pump. Run three tubes from the base of the gumball machine up to the globe. They can follow the path that quarters would have followed as they dropped down.
The three tubes will be
1. Unfiltered water - connected to the canister filter intake
2. Filtered water- connected to the canister filter output
3. Air- connected to the air pump
Plug the filter and pump into a GFCI extension cord and cut a notch in the fiberglass to run the cord outside the base. Please use a GFCI cord so a leak doesn't turn into an injury.
To get the tubes through the coin and gumball distribution mechanism, I had to drill through some of the plastic parts. By this time, I knew how the mechanism work, and I knew that drilling through the side would not impact the gumball distribution. See the image of the tubes coming through that mechanism.
The tubes will also need to go through the acrylic plug you created in the previous step. For that, you need bulkheads. The Zoomed takes a 5/16 inch ID tube, so I special ordered some plastic bulkheads online from a specialty fitting company. Like the acrylic plug, spend some time with the bulkheads they are a critical part that separates wet from dry. Drill through the acryil you cut in the previous step, install bulkheads. Seal with clear silicone rated for aquariums (stuff without a fungicide).
Step 6: Assemble and Decorate
Place the acrylic into the bottom of the globe seal and glue together with clear aquarium silicone. Silicone is your friend. Buy lots of it; use lots of it. (I'm looking for an endorsement deal with the Silicone Producers of America.) After the silicone has dried you should have a watertight globe with three holes in it (two bulkheads for the filter, one bulkhead for air). Do a test in a bathtub or outside or in a small kids pool to check for leaks. Fill it to the top, let it sit for a day or two to detect slow leaks.
To assemble, start with the filter and air pump, run the tubes up the center pole of the machines are you reassemble it from the bottom up. Run the tubes through the dispensing mechanism, throw some gumballs on top of the mechanism (mine holds about 40), plug the tubes into the bulk heads, put the globe on top, fill, and turn everything on.
Before adding fish, rinse out the globe a couple times to get rid of contaminates, and also let your aquarium "cycle". Read up on starting a new tank of aquarium sites or else your fish will very likely die.
To decorate, I wanted it to look as much like a gumball machine as possible. I found some 1" diameter assorted colored beads online that I added as an aquarium substrate to look like the fish are swimming around in gumballs. Make sure if you add beads that they have a density greater than water so they sink and that they aren't toxic to fish. (Also, used one of those beads to make a handle for the back door when the lock was)
I added some fake plants and a push-on magnetic LED light from IKEA. It lights up the globe nicely, and I don't need to run wires since it runs on 3 AAA batteries.
I used color changing LED rope lights wrapped around the base to make the piece pop. They change color automatically (or can be set to a single color). They are controlled by an IR remote. I drilled a hole in the fiberglass for the IR sensor. All the chords, controllers, and plugs for the lights are crammed in the base with the air pump and filter. Only a power cord should run out the back.