Fastest way to waterproof outrunner

Dues to my Maytech assist motor just not having the goods, I’ve purchased Flipsky battle hardened 6384 170Kv motor to see if it will be successful. The rotor already has extra epoxy so I’m not entirely concerned about it, but I need to add some protection to the stator (I’m not bothering to remove sensors either, they can die).
I want a fast way to coat the stator with some protection so that it avoids basic rust etc… The windings should in theory be waterproof already…
I’m thinking one of 2 techniques:

  • Block off bearing holes and spray with a 2K spray
  • Block off bearing holes and paint with JB Weld MarineWeld (can withstand high temps)

Bearings I’ll dip in CorX before placing them back in stator until ceramic arrive.

Anyone got any other novel ideas for a fast way to do this?


Do we know the full waterproofing process used by FoilDrive ?

Yes, they order from Saite and it comes fully waterproofed. I could get from them but there’s a wait time for construction etc. For fast testing I can get motors locally and then just hack them. Once I know what works, then I’ll go to Saite.

Block off bearing holes and epoxy-dipping? When the epoxy is partially cured remove the bearing blocking devices to prevent them to get permanently stuck.

I do it like this:
Tape bearings
Heat in the oven to about 60 deg C for better penetration (epoxy viscosity gets lower and cure time is reduced)
Coat 1 with brush or dip while hot (I use a high temp epoxy for coating)
Let it partially cure, might be 4-6 hours depending on epoxy but just enough to go to a gel/semi solid so that next layer can be applied without affecting the first by running or dripping.
Coat 2 by brush or dip in room temp
Remove tape before full cure to avoid the hassle.

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I’ve been thinking about coating the rotor and stator with pu sealant for some time now. I wonder why it wouldn’t work. From my expirience up to now pu is excellent in salt water but I am not sure what will happen when is heating.

There 2 things, the coating needs to be able to handle higher heat and also needs to allow heat to escape. That means it either needs to be thin, or a thermally conductive coating. There are thermally conductive coatings, but they are much more expensive. I have high heat epoxy here so I figure I’ll probably try a thin coating of that and see what happens…

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I think temp does not get really high if the motor is submerged when under load. A thin coat of normal epoxy works well for me.

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Thanks for your feedback about our motor, we will do some upgrades on the motor based on customers feedbacks, once upgrade version ready we will update soon.

Considering some customers think 6374 not powerful enough, we are also doing a more powerful waterproof motor, pleas stay tuned.