I have designed a magnetic coupling water pump 1 month ago. It separated the motor chamber from the water injection chamber apart. If the motor chamber sealed completely it is 100% waterproof. Now I have changed a little bit for more convenient use and maintenance. All connection parts changed to screw type. It is easy to use.

When printing, some of them need to rotate. I manually add the support layer to the injection chamber and rotate-case.

You will need a ball bearing 630ZZ, 6 neodymium magnets 5X2(diameter X height) and one M3 screw, 2 Hex Socket Screw M3X6 to fix the shaft, motor, etc.

More information on Youtube:
https://youtu.be/sD4r_Rqs6KI

Old version
https://youtu.be/BdqtM83uNWY

https://youtu.be/sD4r_Rqs6KI