500w DD ebay motor with bamboo pegs, what glue?

G

gobi

10 kW
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Jan 9, 2021
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Early summer last year, I hurt the outside of my wrist, putting weight on it brings the pain back.

I wanted to build a simple, light, inexpensive rear DD motor full suspension bike using a free frame I was given by a guy on FB.

I found a 500w DD motor on ebay for $103 and it looked good on paper (claims 40N torque).
I took it apart to check it out as it looked like it has a temp sensor (it does).
Also to spray varnish on the inside.

I used an 8 inch gear puller to pull it apart and I found bamboo pegs holding the motor copper,
the pegs are loosy goosy, moving nearly freely.

Q - what glue can I use to stick the bamboo to the steel?

Also, further inspection, I found server magnets where chipped and missing corners.

WTF, is this advanced motor magnet design for Field Weakening? [sarcasm]
 

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Its a cheap hub motor, left over magnets from the assembly line. Better to reuse the broken magnets and sell for $103 then to throw them out, a penny saved is a penny earned = bigger profit margins. Hastle to return, plus rarely no one opens up a motor when they get it. Cracked magnets are more common, cracked somewhere in the middle, not chipped off the end, but I would triple check somethings not causing it when the stator is in place and spinning.

No real need to use a gear puller, but they are very cheap if your in the USA go to Harbor Freight but its not really necessary as you can take the cover plate off, put the axle on the floor upright on an old rag to not damage the axle end or any threads at the end of the axle, then push the stator off. The issue is the magnets forcing the stator back, but if your careful or have a good technical skills working with your hands and thinking about it then its real easy to take the stator off with your bare hands. Remember the wider the stator, the heavier the motor, the more weight there is, the more force going against what you want to do, taking the stator off. A few days ago I took my stator out of an original style ezee geared motor, 500w'ish style motor and the force was not much at all, as compared to a 35H dd Leaf or a 45H dd Mxus, both are very doable by bare hands and the force is much more substantial.
 
This to That (Glue Advice)

You have another problem to solve before you add glue to this motor: said glue must be rated up to 125C / 257F at a minimum. Otherwise your motor has hot glue flying all over the place and you've got more problems than you had before.

Bamboo expands a little bit when heated, and also in high humidity ( IE: Asia ). The problem is, it wanders and will eventually get destroyed by smacking up against those ridges on the side cover. If your conditions are low humidity ( not Asia ), this natural self destruct sequence will be faster.
 
Jb-weld is the go-to epoxy of choice this end, and is ok at autoclave temps which at 15psi are closer to 135c iirc, a smear covering the whole exposed bamboo should retain it in place even when shrinkage due to the more arid conditions takes place.
At room temperature, J-B Weld™ sets in 4-6 hours to a dark grey color. A full cure is reached in 15-24 hours. J-B Weld™ has a tensile strength of 5020 PSI and sets to a hard bond overnight. It can withstand temperatures up to 550ºF when fully cured.
Click to expand...
 
calab said:
Its a cheap hub motor, left over magnets from the assembly line. Better to reuse the broken magnets and sell for $103 then to throw them out, a penny saved is a penny earned = bigger profit margins. Hastle to return, plus rarely no one opens up a motor when they get it. Cracked magnets are more common, cracked somewhere in the middle, not chipped off the end, but I would triple check somethings not causing it when the stator is in place and spinning.

No real need to use a gear puller, but they are very cheap if your in the USA go to Harbor Freight but its not really necessary as you can take the cover plate off, put the axle on the floor upright on an old rag to not damage the axle end or any threads at the end of the axle, then push the stator off. The issue is the magnets forcing the stator back, but if your careful or have a good technical skills working with your hands and thinking about it then its real easy to take the stator off with your bare hands. Remember the wider the stator, the heavier the motor, the more weight there is, the more force going against what you want to do, taking the stator off. A few days ago I took my stator out of an original style ezee geared motor, 500w'ish style motor and the force was not much at all, as compared to a 35H dd Leaf or a 45H dd Mxus, both are very doable by bare hands and the force is much more substantial.
Click to expand...
I watched Justin take off the side plates with the gear puller and I was sold, bought a cheap 8 inch for $18. Yeah, could not believe how simple it was to take off the side plate.
I was and am still little scared to put my wussy, girly fingers in between the stator and the magnets.

I can't take off the side plate on the wire side as the wire base won't fish through.

I have 2 QS 212s, my town is nearly flat and in the many years I have been on this forum, I am YET to drive some where with hills to ride anything.
I am going for a full suspension, not off road, but something with a few inches of travel for street riding so I don't lose the fillings in my teeth.

OK, I won't worry about the cracked magnets, I will though report it to the seller, I bet the seller won't probably care, but we shall see.
 
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So do I worry about the bamboo pegs moving?

Got it, 2 part high temp epoxy is the proper glue.
Do I apply it on the top edge in RED below?
 

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999zip999 said:
I seen those bamboo twigs and was worried about it too I just pushed them back where they belong and call it a day.
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I am planning on spraying varnish on the motor, I am guessing you did not have any bamboo pegs walk and get broken off ?

Spraying Varnish:
1. Wipe surfaces with 90% alcohol couple of times and let it dry
2. Spray 2 coats? and dry in between

Do I need to oven cure?
 
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