I saw in tis forum different attempts to waterproof the thrusters. Based on some of those ideas I tried my own way to do this. First I also wanted to seal the the windings with epoxy and replace the ball-bearings with inox bearings. Unfortunately I could not find stainless ball bearings in the correct size. I did find however some plastic ball bearings (spare part for rc-cars), but they have an outer diameter of 10mm and therefore don't fit into the original seatings.
So I decided to move on and make room for those plastic bearings.
my first step was to make a dummy for the motor on my lathe and with help of that I made a silicone mould, where I could place the motor core and pot it with epoxy.
Here you see the dummy and the mould
The dummy and the potted motor, still with the original diameter of the bearing-holder
Here you see the plastic ball - bearings and the already adapted motor as well as the new backplate that has also room for the bearing.
before mounting th new backplate, i had to cut down the aluminum holder for the old backplate. the new one (casted resin, I made a mould also for that) fits into the original hole (see below)
before glueing the backplate, the inside of the aluminum tube in the motor needs to be coated with paint or resin
the finished "plastic motor" without any exposed metal parts. The plastic ball bearings do not run as smooth as the metal ones, but its still ok. In the picure also the motor connections are potted.
Of course you can argue wether it makes sense to do so much work on such a cheap motor, but for me it was just another challenge for my Openrov and a sort of "proof of concept" Now that I know how to do and have the moulds it's quite straightforward.
next thing I want to adress is a new and completely different propeller. I have some ideas there...