Most people fidget to some degree or another. Some of us play with pens or bounce our legs or drum on a notepad with a pencil. These fidget toys are another form of distraction to keep your hands busy. Recently different versions of these fidget toys have been popping up everywhere as soon as they caught my attention I knew I wanted a Batman version. In this Instructable I make a Batman logo hand spinner using a cookie cutter as a mold. The body is made from a casting resin that is very easy to work with it. It mixes easily and sets up fast. And the bearings in the center are just old roller skate wheel bearings. I made a prototype that went fairly well. The process is fairly simple, however I did run in to some issues. Since I used this as a chance to experiment with the casting resin and try a few things, varying results were to be expected. One thing I noticed was that it seemed like with each session the castings were harder and harder to remove from the molds. I'm sure if I used a silicone mold or a release agent that I wouldn't have run in to this problem. I plan on doing some more research and giving it another try. Overall I am happy with the end results they aren't as nice as a manufactured or 3D printed one but I still like the way they came out. Also the casting resin was a lot of fun to work with it and gives me plenty of inspiration.
The build video.
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First you are going to need some bearings. These can be found online through Amazon and at Skate shops were they sell skateboard parts. Alternatively if you have some old roller blades or roller skates or an old skate board you don't use anymore you can salvage the bearings from those. I had some old roller blade wheels in my garage and knew that I could use the bearings from those to make the spinners. In order to remove the bearings you just have to wedge them out, they are pressed in place and come out fairly easily. I used a large Allen wrench to pry them out. Each wheel had two bearings.
Here is a close up of the bearing.
The bearings are packed with a thick grease that does not let them spin freely so you have to clean them first. I used some engine degreaser for this but you could also use brake cleaner. I sprayed some of the engine degreaser in to a clean glass jar then dropped all four bearings in to the jar. I closed the lid tightly and swirled it around a bit and then let it sit for about 15 minutes.
After the fifteen minutes I used a magnet to remove the bearings from the jar. To remove any of the leftover engine degreaser I sprayed them dry with an air hose. Be careful if you do this make sure to wear proper protective gear like safety glasses and gloves and a respirator. I made sure they were completely dry before moving on to the next step.
Next I took a piece of blue painters tape and placed it sticky side up on my work table. Then I place my bearings on the tape and with a razor I cut along the outside edge. This will be the masking that will protect the bearing from the resin. I made sure to mask off both sides.
Time to prep the molds. First I taped some wax paper to a perfectly flat piece of scrap MDF. Then I used a glue gun to seal the outer edge of the molds. Once the glue was dry I placed my bearings in the center of each cookie cutter. Try to get as close to center as possible this will make for a better balanced spinner. I added three bearings to the large cookie cutter to add some more weight. These two metal Batman shaped cookie cutters can be purchased from Amazon.
The resin I used is called FastCast, which I purchased through Amazon. It is very easy to work with and uses a 1:1 mix ratio. It sets up very fast in about 10 minutes and cures fully in about 25-30 minutes. I mixed a small batch in a disposable cup and poured them in to my molds. The measuring cups I used are leftovers from old medicine bottles. They hold about 3 teaspoons each. The first batch I mixed was 3 teaspoons of each which was plenty for these two molds, I had some left over in the cup.
Once the resin had cured I removed them from the molds. This was fairly easy the first time. This is one area that did give me trouble as the castings got progressively more difficult to remove with each casting session, I talk more about this later. I used my razor to remove the masking tape from the bearings. I tried not to cut in to the piece itself just the tape.
These castings do require some clean up. So I removed the bearing, by prying them out the same way I did with the roller blade wheels and sanded them down. I used my belt sander for this, here again make sure to wear protective gear this is a very dusty process. In the last picture I was sanding the 3 bearing casting and ruined it. I sanded it too much and was not salvageable. But luckily this is a repeatable process so I made another but this time with just one bearing which is the cover image I used for this Instructable.
Since I was in the mood to experiment I tried a couple of different things. I tried to see if I could get a smoother finish on the bottom side by putting the molds on plastic. This didn't work for me, the plastic caused a lot of wrinkles which required a lot of sanding. As I mentioned earlier the castings were becoming more and more difficult to remove from the molds so I tried using corn starch on the molds to act as a release agent. This didn't work at all, I want to say it made it even harder to remove from the mold. I really think a silicone mold would probably work best for this.
If you attempt this make sure to put a nice and heavy bead of hot glue at the base otherwise the molds will leak. Fortunately this resin sets up so fast that the castings were not completely ruined. You can also see that I am trying different shaped cookie cutters as well.
Once I completed the sanding I spray painted them black. When the paint was dry I added back the bearings and began to fidget until my heart was content. I made several versions, again I just wanted to experiment with the process to see what kind of results I could get with sanding. Overall the small ones are my favorites because I can carry it in my pocket and not even notice its there. I hope you find this Instructable helpful. Thank you for taking the time to read through it. I will try my best to answer any questions you all might have.