Here are the results of test one on the sacrificial stator. What I've learned so far.
1) pull the tape/masking device as soon as the powder has been applied. I waited 2 or 3 minutes.
2) The ends of the Kapton tape can come loose causing open spots or create shade, preventing the powder from dispersing evenly.
3) The powder needs controlled and even disbursement.
Off to the proverbial drawing board to create a powder shaker spreader launcher type thingy

Nice details, looks like you're progressing nicely and will save the rest of us a bunch of trouble on the learning curve.

Is that the HF powder?

I wonder if that will mix with water and make a slurry that can be painted on and then allowed to dry before the heat is used?

Jack

Workin on my first rewind and I was wondering if anyone has tried the Hi-Temp Exhaust Manifold paint from an auto supply store.

Maybe it is not as hard as the powder coat, but it may be tough enough?

Cheers, JR

I took the opposite approach on this side with better results. With everything set, but cold I hand sprinkled powder into the piles that looked good. It took several attempts I just dumped it off and started again. Then I heated it , as piled up as it was, as it heated it lost some coverage and bare metal spots showed up. While still hot I added little piles here and there to get it to flow out more evenly. I like the results.
On the other side I carved out the corners that were overfilled using a new #11 blade it dulled quickly. So at this point a little in the wrong place can be repaired.
As far as masking is concerned the spot that the bearing tube shoulder lands on seems like it is going to be the tricky spot. Taping off the flats inside the teeth would prevent any powder from sticking when applied cold. It should remove easily after cooling, I assume.
The next test is I'm going to soak this stator in several chemicals and see if any of them attack it. If it comes clean I'll use for the tests to refine the process.
As it stands now as sloppy as this one came out it most likely would work fine. Although at this time I don't plan to put wire on this stator because the bell is bent. I think the previous owner tried to pry the bell off with using the edges of the back plate and created concave in the center of it. The bell is a press fit as there are no set screws.

Originally Posted by jjr2001

Workin on my first rewind and I was wondering if anyone has tried the Hi-Temp Exhaust Manifold paint from an auto supply store.

Maybe it is not as hard as the powder coat, but it may be tough enough?

Cheers, JR

Temp is not so much a problem as the PSI that a large gauge wire produces on the material at the corners when bending and pulling on it. I personally am looking to create a radius on the end of the tooth to keep the wire away from the 90* edge. I've experimented with allot of different materials and when built up they are relatively soft, even the epoxy's I've tested. If the radius looses it's shape it dramatically increase the possibilities of a short and do I hate shorts
This particular coating is hard enough to snap the tip on a #11 blade without hardly a scratch in this stuff. Although with the blade edge of the knife it can be carved off if protruding from an edge, but the blade will dull with a few cuts.
My suggestion is try it and let us know.

Originally Posted by zeroback

Temp is not so much a problem as the PSI that a large gauge wire produces on the material at the corners when bending and pulling on it. I personally am looking to create a radius on the end of the tooth to keep the wire away from the 90* edge. I've experimented with allot of different materials and when built up they are relatively soft, even the epoxy's I've tested. If the radius looses it's shape it dramatically increase the possibilities of a short and do I hate shorts

Thanks, that makes sense. So maybe using a dremel and a polishing bit to round the corners of the stator first would be the best way to go and then put on an insulating coating of powder coat or JB-Weld. Time to fire up the dremel.

Cheers, JR

For powder coating I think the sharp edge is needed to keep the stuff acting like a drop of water. I spent many hours trying to polish the sharp edges off stators and haven't found it to be productive. Hit and miss no guarantee all the work will payoff. Although they were 22ish mm or so stators which makes it much harder for the even the Dremal size bits to get into the critical spots. There maybe better results with larger parts.

Originally Posted by zeroback

For powder coating I think the sharp edge is needed to keep the stuff acting like a drop of water. I spent many hours trying to polish the sharp edges off stators and haven't found it to be productive. Hit and miss no guarantee all the work will payoff. Although they were 22ish mm or so stators which makes it much harder for the even the Dremal size bits to get into the critical spots. There maybe better results with larger parts.

And I thought getting the windings on was the hard part......

My stator is a 35mm version so it looks like it would be a little easier to polish.
I think the key to polishing it is to form a good radius which will take a lot of time.
But it sounds like powder is the way to go. Maybe hi-temp paint can be used inside the poles after powder coating the ends for some added insulation.

So now we are back to powder coat. I saw a demo of a plastic pipe device with
a coffee filter in the top that held the powder and then air was injected under the
filter. Then you just heat the stator to 400 deg and lightly dip the stator in the
powder while it is bouncing in the pipe.

Is that the best way or can you just touch the hot stator in a can of powder?

Originally Posted by zeroback

For powder coating I think the sharp edge is needed to keep the stuff acting like a drop of water. I spent many hours trying to polish the sharp edges off stators and haven't found it to be productive. Hit and miss no guarantee all the work will payoff. Although they were 22ish mm or so stators which makes it much harder for the even the Dremal size bits to get into the critical spots. There maybe better results with larger parts.

So if the edge is left as is and the powder brought out to the edge, that will take the "bite" out of the sharp edge well enough? Is that about right?

Jack

Electroplating shops use a sticky backed thin lead tape for masking parts to be chrome plated. I'm thinking maybe this tape could be use to protect the sharp ends of the stator. Overlap the sharp corners by 10thou or so and fold it over. It trims easily with an x-acto or sheetrock knife blade. The lead would be easier to work with than the more common sticky aluminum tapes.

Originally Posted by jjr2001

Is that the best way or can you just touch the hot stator in a can of powder?

Posts 18, 37, 41, as well. Seems to me it should work

Dipping the hot stator is one of the tests I plan as soon as I have another stator ready. I don't think anything is going to clean the first tests from this stator but I have it soaking in Epoxy remover right now.
As far as lead tape that might work better than Kapton for masking, although as an insulator to prevent shorts I get the idea, but it's metal. The other factor is anything used to prevent shorts is space more copper can be. That's why I only want to create a radius on the end, and nothing in the slot. I have wound some real thorn bush stators using the "one time use" plastic caps over the ends, short free every-time. But (again) they are thick and add useless wire hanging off the ends which can also create clearance problems with the bell. I have used Kapton tape as the insulator but it is very time consuming to get it where it is needed.
I think that the PC is going to work I just need to refine the process, if I don't figure out the easiest way I'm sure some one will.

Well I picked up my red powder from HF today and tried what I have seen done on RCG. I used a pickle jar lid with a notch cut out. Put two strands of re-bar wire around the core for a grip. Put the lid on the edge of a table. The notch is so I can dip the core in a vertical orientation.

Used a sanding block with 150 grit machine grade paper until all traces of the old coating was removed. Cleaned both ends with Acetone

Toasted it at about 400 deg F for about 12 minutes. Dipped both ends of the stator a couple of times and it came out like the picture below.

I think I only needed one dip but with a little detail work with either the dremel or a sanding block it should clean up good.

Cheers, JR

Thanks for all the great ideas.

Looks great!

Just make sure with that thickness that you have enough clearance to the ends of the motor when wound.

I'm guessing one dip might be just right.

Thank you for clearing that up!


I also think that the thickness could probably be controlled by the depth of the powder on the surface of the dip pan, or sheet. Seems like a piece of sheet metal would work to lay the powder on.


I don't have a HF nearby, so I don't have the powder and don't know how fine it is. But what I use in casting for applying parting dust evenly to a drag might work for laying down an even layer on a pan for dip powder coating -- if the powder is fine enough.

I put it in an old sock and tie a knot in the end. Then you can just tap the sock and it dispenses the dust evenly.

Originally Posted by vtdiy

Looks great!

Just make sure with that thickness that you have enough clearance to the ends of the motor when wound.

I'm guessing one dip might be just right.

Thank you for clearing that up!

I think one dip would be plenty. The cleanup has started and it is not that hard to do.
I used an xacto blade to cleanup the center mounting hole and I am now ready to clean the outside of the laminations.

With this motor there was a lot of space on the ends but I will probably take a little off each end.
This will flatten them somewhat and thin them down but still
leave that nice rounded edge at the stator edges where the wire will run.

After the cleanup, I think I will put a little 1200 deg F paint on the inside slots of the poles.
Then I should not need any Kapton or other insulators to make winding difficult..

About the thickness, I think you are correct.
What might work is an ultrasonic cleaner or even a home made shaker table.
That way you could put in less powder and get even coverage,
with less cleanup to do after it is coated.

Man, this is fun...

Cheers, JR