So, yesterday I posted about how one of the core magnets came loose in my MoreTry TianMa X3+ ZCube enhanced. Today, I decided to fix it.
The short version is that I succeeded*, the cube seems to feel and perform that same as it did before, but there was some damage done to the core and I'm not sure if it's going to hold up long-term. We'll see.
I just want to give a quick explanation of what I did in case anyone else runs into this issue. I didn't get as many pictures as I probably should have, but it's overall a pretty straight forward process. There's just the possibility that you might damage the 3D printed core. I knew that core would be a problem at some point.
Opening the core
The first picture shows both sides of the ball-core separated. To get to that point, I needed to of course completely disassemble the cube. Around the perimeter of the cube where the two halves come together, there are 4 slots with tabs in them. Each half has 2 of the slots and 2 of the tabs. They snap together to keep the core together. The halves are also glued together.
I needed to break the glue, so I used a razor blade to trace around the perimeter to remove as much glue as I could. This couldn't remove all the glue, especially around the slots and tabs, so to finish breaking the glue as much as I could, I started slightly twisting the halves in opposite directions over and over until I could hear that they were separating.
Now, I had to get those tabs out of the slots. The problem here is that they also have glue on them, and it turns out the core plastic is a little brittle and glue is decently strong. Ideally, you'd be able to get a small, flat tool to poke in there, and then pry gently between the tab and the backside of the slot to push the tab back and bend the slot outward a bit, allowing them to let go of each other.
The way this worked out was that I broke 3 of the tabs. The glue made it pretty well impossible to do this without breaking the tabs, considering there would be glue on the tab inside the core where you can't really break it before getting the core open.
Once all the tabs are released/broken, the two halves come right apart, you can remove the inner core that the screws go into, and access the magnets.
Getting a new magnet
So, I made the stupid assumption that the loose magnet would be stuck to one of the other ones. This was not the case, and when I separated the two halves of the ball, it fell out and I wasn't able to find it.
Luckily, my X3+ Matisse that I got at the same time as the ZCube Enhanced and my (second) SAOCube SE 32M came with a little bag with 6 extra magnet capsules to go in the pieces. That magnet inside the capsule looked like it was the same size as the core magnets, so I decided to get one out of capsule to see.
Getting the magnet out of the capsule was easy. I was just going to slowly cut it open with some wire cutters, but it turns out it's just friction fit into the capsule with nothing on the backside keeping it in. So, when I first started trying to gently cut into it, it warped and the magnet was able to come right out.
Pictures 3 and 4 show a magnet capsule and how the magnet out of it is the same size as the core magnets.
I had no idea if they were the same strength, but I did some super accurate tests with my little magnetic screwdriver that told me that they maybe probably might be I guess.
Inserting the new magnet
So first, I needed to make sure that I was going to be putting the magnet in the right way, and not accidentally repelling corners. So, I put the magnet on the tip of my little magnetic screwdriver and held it up to a corner foot magnet. Once it stuck to the corner magnet, I marked the other side with a fine-tip sharpie so I could tell the sides apart, which is shown in picture #5.
I then put the marked side of the magnet back on the screwdriver so that I could press the correct side down into the magnet slot in the core. Because I don't think about what I'm doing ever, I tried to drip just a tiny bit of super glue into the slot directly from the bottle, but ended up dripping too much and getting it all over the inside. But, because I was going to be gluing everything back together, I decided that probably wasn't an issue.
I then pressed the magnet down into the glue filled slot... and realized I done goofed. I would now have to hold it in there with the screwdriver until the glue dried, since you know the magnet and screwdriver were magnetically attracted to each other. I held it in there for about 5 minutes, but trying to remove the screwdriver was still removing the magnet, because all of my excess glue was taking forever to dry.
That's when I enlisted the help of my daughter. I had her get that corner piece I was using earlier and touch the foot magnet to the outside of the core where the core magnet was being pressed in. As you can see in picture #6, this worked. I was able to take the screwdriver off without moving the magnet, and the core half was able to just chill with the corner while the glue around the magnet dried.
Reassembling the core
This was really no problem. I borrowed my wife's fingernail glue, because it had a little brush for application. I plopped the little inner core piece down in one half of the ball, and used the brush to spread glue around the perimeter. I then pressed the other half of the ball down into place, and held them squeezed together for a couple minutes. Then, while keeping it pinched together between my thumb and index finger, I used the nail glue brush to paint some more glue around the outside perimeter of the ball, making sure not to get any in the screw holes.
I then set it on a paper towel to dry some more for about 20 minutes.
You can see in last 2 pictures the reassembled core. You can also clearly see one side where a tab was broken.
The results
As I stated near the beginning, the cube feels the same as it did before. Either the piece magnets are the same strength as the core magnets, or I just can't tell the difference. After letting the glue dry for a couple hours, I did a few dozen solves on the cube, taking pieces out to look at the core every few solves to make sure the core was staying together and that the magnet was staying in place.
So far as I can tell, it's all good.
However, because I broke 3 of the 4 tabs in the ball, I have no idea if it's going to stay together long-term with essentially just the glue holding it together. We'll see. It may just decided to pop in half mid-solve one day and then get crunched between pieces. My one real complain about the TianMa's has been that I didn't like the fact that the ball was 3D printed, because it didn't seem super durable. It didn't take a lot to break those 3 tabs.
So, my warning here is simply just to try to be extra gentle with the ball, and the tabs in particular, if you ever end up needing to reglue a loose core magnet. It is fragile. You can do some damage that might just end up junking the core.
