I decided that my fridge was too boring, so I opted to use some InstaMorph to make custom marble run pieces.Because why not? And because thermoplastic makes it easy to create whatever kind of shapes you want.
It was also decided that the marble run should make noise, so I included a few items along those lines. This is a pretty simple initial version, but it should help get you started in making your own.
Check the final step for a video of the magnetic musical marble run in action!
Step 1: Materials
- InstaMorph or other thermoplastic
- Strong magnets
- Aluminum foil
- Pot or large bowl for hot water
- Tongs, etc for pulling plastic out of hot water
- Pipe/Square dowels
- Plastic bottle
- Noisy doodads (washers, bolts, etc)
- Thin wire or string
Step 2: Angle Tracks
I made two types of tracks, using different mold materials I had on hand.
The first was a v-shaped one. To make this, I took a piece of thermoplastic, pressed it flat and stretched it until it was the length I wanted for my track, and as wide as two sides of the square dowel.
Wrap the plastic longways around two adjacent sides of the dowel, and let it cool. Depending on what mold material you're working with, it might want to stick to the dowel, so one option is to cover the item with aluminum foil, which will allow you to remove the plastic more easily.
The easiest way to make cuts in this kind of plastic is with scissors, while it's still somewhat soft. After it's fully cooled, it's easiest to make cuts with a craft knife or dremel. So you can trim down the edges if you'd like it to look a little cleaner.
To attach the magnets, it's easiest to encase them in a bit of plastic, and then mold it to match the weird angle you're going to need to make the track upright. You can just take one edge of it and fold it over to the "wrong" side of the magnet (the side that doesn't want to grab onto your fridge). While they're still pretty hot, take your magnet holders and squish them onto the outside of either end. You can place them against a flat surface to get them even before they cool.
Step 3: Half-pipe Tracks
This track is very similar to the angled one. Make sure that the pipe or cylinder you're using is larger than the size of your marble. It's good to have it be a bit bigger so there's room for it to catch a marble falling onto it.
Like the last one, make a flat piece of plastic and bend it halfway around the pipe. Again, you can trim it down using scissors. And attach magnets surrounded by plastic the same way as in the last step.
Step 4: Funnel
For my funnel, I used a plastic water bottle as my mold. The nice thing about using a squishable bottle for this is that you can collapse one side before molding the thermoplastic around it so that it'll sit flat against the fridge. Crumple one side as flat as possible (don't worry if it's not perfect), and cover the end with foil. The thermoplastic will stick to it, so you need to make sure you have a barrier.
Roll a good sized ball of InstaMorph out (we didn't have a rolling pin at Crashspace; we did have a Sparkfun beer stein. Go figure.) until it's large enough to go around the end of your bottle. You can roll the bottle over top to check that it'll wrap around with a little bit of overlap.
Make sure your sheet of InstaMorph is still mostly clear (you can drop it back in your hot water if needed), and wrap it around the covered end of the bottle. Keep the end at the mouth of the bottle open. I accidentally closed it off while trimming with my scissors, and you can find a way to reopen it (which I did by poking something through and widening the hole), or drill a hole after it's cooled, but that's an unnecessary pain.
Once it's cooled a little bit (not clear anymore, but not hard yet), you can pull it off the bottle and continue cleaning up the shape. Laying the flat side against the table means you can get the shape just the way you want. Once again, scissors are good.
When the funnel is mostly cooled, repeat the steps for adding magnets. You can place a sheet on top of the magnet on the back, flat side of the funnel, or enclose it entirely in plastic first. Before it's cooled entirely, make sure the hole at the bottom is large enough for your marble.
Step 5: Bell
I wanted to include a bell at the end of my run, so I made a removable holder from InstaMorph as well.
The base is plastic, so once again I wrapped it in foil. I rolled a snake of the thermoplastic, wrapped it around the base, and then smushed it so it had a flat edge against the table while still covering part of the base (see pictures).
I repeated the same method for enclosing a magnet in some plastic, but this time I attached them off to the side. Because the part of the bell that I want my marble to hit is so much further out, I didn't want to make this piece of the run even farther away from the fridge.
Make sure you attach the magnets off to the side securely. These are the ones most likely to fall off if you don't make sure they stick together well.
Step 6: Chimes Bar
This is the most complicated element of the build, but it's also super neat.
Roll out a nice smooth snake of plastic and allow it to cool. Your thermoplastic-enclosed magnets should wrap at least most of the way around it. One they're in place, you can mold them until the bar will be about the same distance from the fridge surface as the center of your tracks.
Grab some items that will make sound when struck by the marble. I like using metal pieces, like washers, nuts and bolts, D-rings, belt buckles, whatever I have on hand. You can attach them with string, but I like that extra bit of control that comes with wire.
Wrap one end around the bar a couple times, then string the item onto the wire. For subsequent items, you'll want to make sure the bottoms are in line with the first so the marble can hit them all.
Once you have this item on the fridge, putting it at an angle means that the dangly noisemakers are likely to slip. To counter this, I put a small amount of hot glue on top of the wires on the bar.
Test it with one of your tracks. Adjust.
Step 7: Fin
Attach all of your pieces to the fridge and go nuts! Try making another element with a different shape, or make a ton of them to go all the way from the top to the floor. Perhaps you have access to a magnetic white board; surely it could benefit from a marble run. Let me know in the comments if you have other ideas for elements I should add to my fridge.
Also, make sure to check out the video of my InstaMorph magnetic marble run in action, and have fun!