I guess my original question should’ve been–so how are these microballoons different than what’s used in the video?
I did my first set of motors with milliput 
After doing the first can the milliput was not smooth anymore so in the end I had to mix it 4 times (it stays nice for about 30-45 minutes). Also the cleaning should be done as early as possible with wet and dry clothes maybe within 20 minutes, afterwards it takes much more time. A bit annoying is that the 2 parts should be mixed for at least 7 minutes, after the first time I mixed it for 5 minutes and even that feels endless.
milliput sticks like hell, not as my previous epoxy putty. I’m quite satisfied with the result.
I also like to battle harden the stators to secure the (loose) windings. I also found loose windings when inspecting with a tooth pick which I could move.
When battle harden the stators I was better prepared, I sticked baking paper with masking tape to the table so I could use both hands to roll the rods which is way better. The first time I didn’t stick the baking paper which was bad.
For one can I used 1cm of each milliput part and for one stator 1,3 - 1,5cm. I would say it takes 2-3 hours to battle harden and clean 2 complete motors.
Also covered the hall sensor pins on the PCB.
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Maybe milliput isn’t ideal being so hard. Maybe. A bit of flex when expanding from heat is good. Good to 130c…wonder what temp the magnet wire will get to.
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awesome
how hard does the milliput set to? I mean is it really hard like a metal, or kinda hard like a plastic? I’m interested in hearing your opinion in like 1000 kms… the qwik steel i’m planning on testing get’s hard like steel… make a ball out of it and you could almost (almost) use it as a bearing…
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The epoxy putty which I used before was up to 120°C. It didn’t fall off after many months of abuse including running the motors sizzling hot in summer, sometimes above 85°C (no temperature sensor), I couldn’t touch them anymore. This summer will tell how the milliput survives but I think it will be fine. BTW my closed Maytech’s reached 70°C today (outside 18°C only), ok with 100A each motor, that’s the spring setting.
Hard as a rock, don’t know if hard as steel 
It’s very solid but could be a little bit brittle (like the putty I used before). With brittle I mean you can damage or scratch it e.g. with a small flat screwdriver with enough force but this is no problem.
Ok I just tried to destroy the milliput with a massive knife for science.
It’s strong! I stabbed, peeled, chipped, sliced for minutes and put several times almost my full body weight on the blade. The only way is to shave it or scrape in V shape. So maybe not as hard as rock but still hard as rock 
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thanks buddy…
objectively Milliput looks good from my point of view if it sticks really good, is hard but somewhat flexy, I’m following your experiences… this look like an easier method than normal epoxy or epoxy and micro-balloons…
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It sticks too good for my taste 
I’ll battle harden another 2 motors with milliput and gonna share here if it hold up well like I expect. And I won’t be nice to the motors, the ones from the pics above are for MTB and the second set for freestyle MTB.
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I’d be interested if you have some spare magnets or similar in steel that you could pseudo-battle harden and then destructively break apart the bond…
you know… for science…
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Be nine if they had a temp reading before and after.
Where’s urs @kook with the metal filled epoxy on the magnets?
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Do you mean the glue between magnet and rotor? BTW no idea how to remove a magnet 
guess with heat but with how much?
The heat will ruin the magnets at some unknown temp with almost all the magnet motors
no… emulate the bond with milliput with the magnets edge and/or thin steel, cure it… attempt to break the bond between milliput and magnets
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It’s comming… I’m all over the place with projects…
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True, would be interesting to see the temp difference before and after battle hardening. Or in a perfect world to have 2 equal boards ridden on the same day for accurate comparison.
Slightly offtopic but how to remove a single magnet e.g. for a replacement without damaging the others?
Now I get you, I can try this within the next days…
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if you really want to get the magnets from a motor bell, soak the bell in an acetone vapor bath for a day or two…
get jar… put in bell…put in acetone…1/2ish covering magnets… cover jar (i use glass jars) put in hot sun for 1/2 day, rotate 180 degrees… check acetone level… retop up in necessary… put back out in the sun…
usually 1 hot day is enough to dissolve the magnet holding glue
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Hmmm sounds like I prefer to buy a new motor in this case 
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a single… I haven’t figgured out a fool-proof non-destructive method… even with the magnet glue dissolved the magnets stick to the bell like a muther-fucker
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Maybe do the acetone dip with the other magnets covered in wax. Maybe. I’ve had rotors that had epoxy which wouldn’t soften with acetone though even after over a week.
R scratch that and seems acetone will remove wax
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Meanwhile I battle hardened a second set (closed Maytech’s), this time I was much faster and also left some holes on the windings for hopefully better heat dissipation.
From my experience with Maytech the most important step is to stop cable movement with epoxy, IMO more important than battle hardening itself.
First I cut most of the outter shrink tube.
I covered the 2 mounting holes with kapton tape and then glued everything inside and outside with milliput.
Next time I order standard black milliput. I think superfine is not necessary plus mixing two white components is annyoing because you don’t see when it’s properly mixed that’s why they write at least 7 minutes. I need it black anyway.
@kook you wanted some tests of milliput on steel, here it is. This is the most stupid video I’ve ever done
So when the steel is at 145°C the milliput has 75° and doesn’t stick anymore but normally thermal throtteling kicks in at 80°C so it should be fine. But on the other side actually my motors getting 60°-80°C hot and it’s not summer. I wonder which temperature the milliput has after riding with hot motors. I can measure it and we gonna see.
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Do any of you guys know of a cheap supplier of Glass Microspheres or Fumed Silica in Europe?
Preferably Glass Microspheres as they are lighter
The only links that I found with a reasonable price are this ones