Motor waterproofing and replacing phase wires

About to coat my motor (BDUAV 6384 120KV out-runner) with epoxy, have pulled the rotor and stator apart and have a couple of questions…

  1. How do you pull the top off the stator so I can uncover the top of the windings and access where the phase wires are soldered?
  2. Will adding a layer of epoxy to the magnets and the outside of the stator cause it to jam (there is not a lot of clearance at a guess < 0.5mm)?
  3. I have purchased a flexible potting epoxy (can handle heat)… is that ok to use or should I use regular epoxy?
  4. The motor comes with 16AWG wires - I will replace with 12AWG - is this correct?


You can use the search, this has been discussed many times.

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Thanks Vladimir - unfortunately I have not yet found the specific answers to my questions… hence the post.

This is what I have found:

  1. The only resource I can find that details how to remove the top off the BDUAV 6384 motor is this youtube video 6384 outrunner motor disassembly.
    I did find this reply to a post which suggests “With low amount of heat and a gentle whack from the back, I stuffed a paper towel where the back bearings sit, placed a socket head 18mm OD, came out in no time” but I am not sure where to apply the heat and my bearings are out already.
  2. Some of the posts on this forum mention adding 1 or 2 coats to the windings and some none, instead opting for a coating of Corrosion-X. Others have 3D printed moulds to sit the stator in then pour in epoxy, others discuss using a lathe to clean off the stator after coating in epoxy. But I could not find a simple answer ie 1 coat of epoxy will be ok on the outside of the stator - ie do you need to clean/sand/lathe it off or is there clearance. I will try 1 layer and see. Likewise for inside the rotor - some thing - people using a lathe to clean off. Just not exactly sure of tolerances. I guess it’s a matter of trying… then remove if it jams.
  3. Found posts discussing whether to use thermal or regular epoxy (apparently either will do), nothing specifically about flexible thermal epoxy for the motor. I did see one topic about flexible epoxies… but not to do with the motor.
  4. The same guy who did the above video discusses replacing the phase wires with 12AWG - see his follow up video: 6384 Outrunner wire replacement

As per youtube video mentioned above… was able to remove top motor cover by inserting a 13mm socket with extension (after removing all bearings first), hold the stator in my hand and whack the socket with a block of wood. Nothing damaged/all surfaces look good.

I have the same motor, I had a pretty bad experience with coating it. I suggest you use a very thin coat of epoxy, in my first attempt I messed up by covering it with a too thick layer, the result was that I was unable to reassemble the stator and the outer rotor was not able to freely rotate. This is my post Slow build from Italy + Avoid my mistakes!

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This is a question for those who have resined their motors…
Does the resin actually flow through into all the windings or is the idea to simply apply a layer that spans across all the windings - like a gap filler… so you don’t need it to go into all the tiny gaps between the wires?
I have read that some people heat it up first… which I have tried (putting it in the sun for 20 minutes), but my resin had too much of an exothermic reaction… bubbled up and went hard very rapidly - thank goodness my stator was not in it.

My concern dipping or painting/brushing it on… is that unless it is a perfect seal, water will get inside and corrode from within .

Is it possible to get good results without a vacuum system? If not, should I simply using CorrosionX after each use and not bother with resin?


I wrap the stator with a projector sheet (cut to size). Then I seal the base with wax. Then I pour slow cure epoxy into the stator so that is gets onto everything and seals properly.


What jezza said. I used west lam epoxy heated to 40deg but it did not flow trough winding since I forgot to heat up the motor also. Next time I will either use entropy epoxy or urethane eg simpact 85a , could also add thinner to normal epoxy perhaps

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with a full pour it’s adviseable to use thermal epoxy, some have burnt their motors due to poor heat transfer with normal epoxy and full potting.


Hmm. When tou say burned, do you mean the winding copper wire literally melting?

Yes, I use thermal conducting epoxy. But others haven’t and their motors seem ok. If you using it for an assist it should be fine. For efoil then I’d say thermal conductivity is way more important.

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No, the insulation burns, and the motor short circuits, sometimes taking the esc out with it. I do two light coats of normal epoxy on my motors, has worked well, but if you can get your hands on thermal epoxy or another thermal potting compound it’s even better.


I read somewhere on this forum that you can also add microballoons to the epoxy to reduce the weight.

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Thanks everyone for your input.

@Jezza When you remove the projector sheet - do you coat the outside of the stator?

@Larsb How do you apply the epoxy, paint brush? - and does it create a seal over all the windings (therefore a thicker resin would be better??)- or can water get in between?

Did you have a link for the thermal epoxy? Im finding it pretty hard to track down local.

I removed it after the epoxy had set and then used a high temp epoxy spray on the outside of the stator to finish it off.

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If you are in europe then EC is the serious one-stop-shop.

I’m experimenting with some «potting glue for electronics» from Ali at the moment and most of them seem to be fully functional molding silicone of varying hardness. Be aware that most silicone wil need a week to cure at thicker layers.

yes, you’d need to spend some time googling, I don’t have a source.

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Apply with a brush on a stator that’s preheated to 40 deg C in the oven. I use normal laminating epoxy resin but high temp version. Just when the first coat isn’t sticky anymore i apply the second.
There are also winding varnish that you can use like:
You need to select one with the right properties.

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